FFmpeg/libavformat/utils.c

/*
 * various utility functions for use within FFmpeg
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "avformat.h"
#include "internal.h"
#include "libavcodec/opt.h"
#include "metadata.h"
#include "libavutil/avstring.h"
#include "riff.h"
#include "audiointerleave.h"
#include <sys/time.h>
#include <time.h>
#include <strings.h>
#include <stdarg.h>
#if CONFIG_NETWORK
#include "network.h"
#endif

#undef NDEBUG
#include <assert.h>

/**
 * @file libavformat/utils.c
 * various utility functions for use within FFmpeg
 */

unsigned avformat_version(void)
{
    return LIBAVFORMAT_VERSION_INT;
}

const char *avformat_configuration(void)
{
    return FFMPEG_CONFIGURATION;
}

const char *avformat_license(void)
{
#define LICENSE_PREFIX "libavformat license: "
    return LICENSE_PREFIX FFMPEG_LICENSE + sizeof(LICENSE_PREFIX) - 1;
}

/* fraction handling */

/**
 * f = val + (num / den) + 0.5.
 *
 * 'num' is normalized so that it is such as 0 <= num < den.
 *
 * @param f fractional number
 * @param val integer value
 * @param num must be >= 0
 * @param den must be >= 1
 */
static void av_frac_init(AVFrac *f, int64_t val, int64_t num, int64_t den)
{
    num += (den >> 1);
    if (num >= den) {
        val += num / den;
        num = num % den;
    }
    f->val = val;
    f->num = num;
    f->den = den;
}

/**
 * Fractional addition to f: f = f + (incr / f->den).
 *
 * @param f fractional number
 * @param incr increment, can be positive or negative
 */
static void av_frac_add(AVFrac *f, int64_t incr)
{
    int64_t num, den;

    num = f->num + incr;
    den = f->den;
    if (num < 0) {
        f->val += num / den;
        num = num % den;
        if (num < 0) {
            num += den;
            f->val--;
        }
    } else if (num >= den) {
        f->val += num / den;
        num = num % den;
    }
    f->num = num;
}

/** head of registered input format linked list */
AVInputFormat *first_iformat = NULL;
/** head of registered output format linked list */
AVOutputFormat *first_oformat = NULL;

AVInputFormat  *av_iformat_next(AVInputFormat  *f)
{
    if(f) return f->next;
    else  return first_iformat;
}

AVOutputFormat *av_oformat_next(AVOutputFormat *f)
{
    if(f) return f->next;
    else  return first_oformat;
}

void av_register_input_format(AVInputFormat *format)
{
    AVInputFormat **p;
    p = &first_iformat;
    while (*p != NULL) p = &(*p)->next;
    *p = format;
    format->next = NULL;
}

void av_register_output_format(AVOutputFormat *format)
{
    AVOutputFormat **p;
    p = &first_oformat;
    while (*p != NULL) p = &(*p)->next;
    *p = format;
    format->next = NULL;
}

int av_match_ext(const char *filename, const char *extensions)
{
    const char *ext, *p;
    char ext1[32], *q;

    if(!filename)
        return 0;

    ext = strrchr(filename, '.');
    if (ext) {
        ext++;
        p = extensions;
        for(;;) {
            q = ext1;
            while (*p != '\0' && *p != ',' && q-ext1<sizeof(ext1)-1)
                *q++ = *p++;
            *q = '\0';
            if (!strcasecmp(ext1, ext))
                return 1;
            if (*p == '\0')
                break;
            p++;
        }
    }
    return 0;
}

static int match_format(const char *name, const char *names)
{
    const char *p;
    int len, namelen;

    if (!name || !names)
        return 0;

    namelen = strlen(name);
    while ((p = strchr(names, ','))) {
        len = FFMAX(p - names, namelen);
        if (!strncasecmp(name, names, len))
            return 1;
        names = p+1;
    }
    return !strcasecmp(name, names);
}

#if LIBAVFORMAT_VERSION_MAJOR < 53
AVOutputFormat *guess_format(const char *short_name, const char *filename,
                             const char *mime_type)
{
    return av_guess_format(short_name, filename, mime_type);
}
#endif

AVOutputFormat *av_guess_format(const char *short_name, const char *filename,
                                const char *mime_type)
{
    AVOutputFormat *fmt, *fmt_found;
    int score_max, score;

    /* specific test for image sequences */
#if CONFIG_IMAGE2_MUXER
    if (!short_name && filename &&
        av_filename_number_test(filename) &&
        av_guess_image2_codec(filename) != CODEC_ID_NONE) {
        return av_guess_format("image2", NULL, NULL);
    }
#endif
    /* Find the proper file type. */
    fmt_found = NULL;
    score_max = 0;
    fmt = first_oformat;
    while (fmt != NULL) {
        score = 0;
        if (fmt->name && short_name && !strcmp(fmt->name, short_name))
            score += 100;
        if (fmt->mime_type && mime_type && !strcmp(fmt->mime_type, mime_type))
            score += 10;
        if (filename && fmt->extensions &&
            av_match_ext(filename, fmt->extensions)) {
            score += 5;
        }
        if (score > score_max) {
            score_max = score;
            fmt_found = fmt;
        }
        fmt = fmt->next;
    }
    return fmt_found;
}

#if LIBAVFORMAT_VERSION_MAJOR < 53
AVOutputFormat *guess_stream_format(const char *short_name, const char *filename,
                             const char *mime_type)
{
    AVOutputFormat *fmt = av_guess_format(short_name, filename, mime_type);

    if (fmt) {
        AVOutputFormat *stream_fmt;
        char stream_format_name[64];

        snprintf(stream_format_name, sizeof(stream_format_name), "%s_stream", fmt->name);
        stream_fmt = av_guess_format(stream_format_name, NULL, NULL);

        if (stream_fmt)
            fmt = stream_fmt;
    }

    return fmt;
}
#endif

enum CodecID av_guess_codec(AVOutputFormat *fmt, const char *short_name,
                            const char *filename, const char *mime_type, enum AVMediaType type){
    if(type == AVMEDIA_TYPE_VIDEO){
        enum CodecID codec_id= CODEC_ID_NONE;

#if CONFIG_IMAGE2_MUXER
        if(!strcmp(fmt->name, "image2") || !strcmp(fmt->name, "image2pipe")){
            codec_id= av_guess_image2_codec(filename);
        }
#endif
        if(codec_id == CODEC_ID_NONE)
            codec_id= fmt->video_codec;
        return codec_id;
    }else if(type == AVMEDIA_TYPE_AUDIO)
        return fmt->audio_codec;
    else
        return CODEC_ID_NONE;
}

AVInputFormat *av_find_input_format(const char *short_name)
{
    AVInputFormat *fmt;
    for(fmt = first_iformat; fmt != NULL; fmt = fmt->next) {
        if (match_format(short_name, fmt->name))
            return fmt;
    }
    return NULL;
}

/* memory handling */


int av_get_packet(ByteIOContext *s, AVPacket *pkt, int size)
{
    int ret= av_new_packet(pkt, size);

    if(ret<0)
        return ret;

    pkt->pos= url_ftell(s);

    ret= get_buffer(s, pkt->data, size);
    if(ret<=0)
        av_free_packet(pkt);
    else
        av_shrink_packet(pkt, ret);

    return ret;
}


int av_filename_number_test(const char *filename)
{
    char buf[1024];
    return filename && (av_get_frame_filename(buf, sizeof(buf), filename, 1)>=0);
}

static AVInputFormat *av_probe_input_format2(AVProbeData *pd, int is_opened, int *score_max)
{
    AVInputFormat *fmt1, *fmt;
    int score;

    fmt = NULL;
    for(fmt1 = first_iformat; fmt1 != NULL; fmt1 = fmt1->next) {
        if (!is_opened == !(fmt1->flags & AVFMT_NOFILE))
            continue;
        score = 0;
        if (fmt1->read_probe) {
            score = fmt1->read_probe(pd);
        } else if (fmt1->extensions) {
            if (av_match_ext(pd->filename, fmt1->extensions)) {
                score = 50;
            }
        }
        if (score > *score_max) {
            *score_max = score;
            fmt = fmt1;
        }else if (score == *score_max)
            fmt = NULL;
    }
    return fmt;
}

AVInputFormat *av_probe_input_format(AVProbeData *pd, int is_opened){
    int score=0;
    return av_probe_input_format2(pd, is_opened, &score);
}

static int set_codec_from_probe_data(AVFormatContext *s, AVStream *st, AVProbeData *pd, int score)
{
    AVInputFormat *fmt;
    fmt = av_probe_input_format2(pd, 1, &score);

    if (fmt) {
        av_log(s, AV_LOG_DEBUG, "Probe with size=%d, packets=%d detected %s with score=%d\n",
               pd->buf_size, MAX_PROBE_PACKETS - st->probe_packets, fmt->name, score);
        if (!strcmp(fmt->name, "mp3")) {
            st->codec->codec_id = CODEC_ID_MP3;
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        } else if (!strcmp(fmt->name, "ac3")) {
            st->codec->codec_id = CODEC_ID_AC3;
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        } else if (!strcmp(fmt->name, "eac3")) {
            st->codec->codec_id = CODEC_ID_EAC3;
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        } else if (!strcmp(fmt->name, "mpegvideo")) {
            st->codec->codec_id = CODEC_ID_MPEG2VIDEO;
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
        } else if (!strcmp(fmt->name, "m4v")) {
            st->codec->codec_id = CODEC_ID_MPEG4;
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
        } else if (!strcmp(fmt->name, "h264")) {
            st->codec->codec_id = CODEC_ID_H264;
            st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
        } else if (!strcmp(fmt->name, "dts")) {
            st->codec->codec_id = CODEC_ID_DTS;
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        } else if (!strcmp(fmt->name, "aac")) {
            st->codec->codec_id = CODEC_ID_AAC;
            st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
        }
    }
    return !!fmt;
}

/************************************************************/
/* input media file */

/**
 * Open a media file from an IO stream. 'fmt' must be specified.
 */
int av_open_input_stream(AVFormatContext **ic_ptr,
                         ByteIOContext *pb, const char *filename,
                         AVInputFormat *fmt, AVFormatParameters *ap)
{
    int err;
    AVFormatContext *ic;
    AVFormatParameters default_ap;

    if(!ap){
        ap=&default_ap;
        memset(ap, 0, sizeof(default_ap));
    }

    if(!ap->prealloced_context)
        ic = avformat_alloc_context();
    else
        ic = *ic_ptr;
    if (!ic) {
        err = AVERROR(ENOMEM);
        goto fail;
    }
    ic->iformat = fmt;
    ic->pb = pb;
    ic->duration = AV_NOPTS_VALUE;
    ic->start_time = AV_NOPTS_VALUE;
    av_strlcpy(ic->filename, filename, sizeof(ic->filename));

    /* allocate private data */
    if (fmt->priv_data_size > 0) {
        ic->priv_data = av_mallocz(fmt->priv_data_size);
        if (!ic->priv_data) {
            err = AVERROR(ENOMEM);
            goto fail;
        }
    } else {
        ic->priv_data = NULL;
    }

    if (ic->iformat->read_header) {
        err = ic->iformat->read_header(ic, ap);
        if (err < 0)
            goto fail;
    }

    if (pb && !ic->data_offset)
        ic->data_offset = url_ftell(ic->pb);

#if LIBAVFORMAT_VERSION_MAJOR < 53
    ff_metadata_demux_compat(ic);
#endif

    ic->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;

    *ic_ptr = ic;
    return 0;
 fail:
    if (ic) {
        int i;
        av_freep(&ic->priv_data);
        for(i=0;i<ic->nb_streams;i++) {
            AVStream *st = ic->streams[i];
            if (st) {
                av_free(st->priv_data);
                av_free(st->codec->extradata);
            }
            av_free(st);
        }
    }
    av_free(ic);
    *ic_ptr = NULL;
    return err;
}

/** size of probe buffer, for guessing file type from file contents */
#define PROBE_BUF_MIN 2048
#define PROBE_BUF_MAX (1<<20)

int ff_probe_input_buffer(ByteIOContext **pb, AVInputFormat **fmt,
                          const char *filename, void *logctx,
                          unsigned int offset, unsigned int max_probe_size)
{
    AVProbeData pd = { filename ? filename : "", NULL, -offset };
    unsigned char *buf = NULL;
    int ret = 0, probe_size;

    if (!max_probe_size) {
        max_probe_size = PROBE_BUF_MAX;
    } else if (max_probe_size > PROBE_BUF_MAX) {
        max_probe_size = PROBE_BUF_MAX;
    } else if (max_probe_size < PROBE_BUF_MIN) {
        return AVERROR(EINVAL);
    }

    if (offset >= max_probe_size) {
        return AVERROR(EINVAL);
    }

    for(probe_size= PROBE_BUF_MIN; probe_size<=max_probe_size && !*fmt && ret >= 0;
        probe_size = FFMIN(probe_size<<1, FFMAX(max_probe_size, probe_size+1))) {
        int ret, score = probe_size < max_probe_size ? AVPROBE_SCORE_MAX/4 : 0;
        int buf_offset = (probe_size == PROBE_BUF_MIN) ? 0 : probe_size>>1;

        if (probe_size < offset) {
            continue;
        }

        /* read probe data */
        buf = av_realloc(buf, probe_size + AVPROBE_PADDING_SIZE);
        if ((ret = get_buffer(*pb, buf + buf_offset, probe_size - buf_offset)) < 0) {
            /* fail if error was not end of file, otherwise, lower score */
            if (ret != AVERROR_EOF) {
                av_free(buf);
                return ret;
            }
            score = 0;
            ret = 0;            /* error was end of file, nothing read */
        }
        pd.buf_size += ret;
        pd.buf = &buf[offset];

        memset(pd.buf + pd.buf_size, 0, AVPROBE_PADDING_SIZE);

        /* guess file format */
        *fmt = av_probe_input_format2(&pd, 1, &score);
        if(*fmt){
            if(score <= AVPROBE_SCORE_MAX/4){ //this can only be true in the last iteration
                av_log(logctx, AV_LOG_WARNING, "Format detected only with low score of %d, misdetection possible!\n", score);
            }else
                av_log(logctx, AV_LOG_DEBUG, "Probed with size=%d and score=%d\n", probe_size, score);
        }
    }

    if (!*fmt) {
        av_free(buf);
        return AVERROR_INVALIDDATA;
    }

    /* rewind. reuse probe buffer to avoid seeking */
    if ((ret = ff_rewind_with_probe_data(*pb, buf, pd.buf_size)) < 0)
        av_free(buf);

    return ret;
}

int av_open_input_file(AVFormatContext **ic_ptr, const char *filename,
                       AVInputFormat *fmt,
                       int buf_size,
                       AVFormatParameters *ap)
{
    int err;
    AVProbeData probe_data, *pd = &probe_data;
    ByteIOContext *pb = NULL;
    void *logctx= ap && ap->prealloced_context ? *ic_ptr : NULL;

    pd->filename = "";
    if (filename)
        pd->filename = filename;
    pd->buf = NULL;
    pd->buf_size = 0;

    if (!fmt) {
        /* guess format if no file can be opened */
        fmt = av_probe_input_format(pd, 0);
    }

    /* Do not open file if the format does not need it. XXX: specific
       hack needed to handle RTSP/TCP */
    if (!fmt || !(fmt->flags & AVFMT_NOFILE)) {
        /* if no file needed do not try to open one */
        if ((err=url_fopen(&pb, filename, URL_RDONLY)) < 0) {
            goto fail;
        }
        if (buf_size > 0) {
            url_setbufsize(pb, buf_size);
        }
        if ((err = ff_probe_input_buffer(&pb, &fmt, filename, logctx, 0, logctx ? (*ic_ptr)->probesize : 0)) < 0) {
            goto fail;
        }
    }

    /* if still no format found, error */
    if (!fmt) {
        err = AVERROR_INVALIDDATA;
        goto fail;
    }

    /* check filename in case an image number is expected */
    if (fmt->flags & AVFMT_NEEDNUMBER) {
        if (!av_filename_number_test(filename)) {
            err = AVERROR_NUMEXPECTED;
            goto fail;
        }
    }
    err = av_open_input_stream(ic_ptr, pb, filename, fmt, ap);
    if (err)
        goto fail;
    return 0;
 fail:
    av_freep(&pd->buf);
    if (pb)
        url_fclose(pb);
    if (ap && ap->prealloced_context)
        av_free(*ic_ptr);
    *ic_ptr = NULL;
    return err;

}

/*******************************************************/

static AVPacket *add_to_pktbuf(AVPacketList **packet_buffer, AVPacket *pkt,
                               AVPacketList **plast_pktl){
    AVPacketList *pktl = av_mallocz(sizeof(AVPacketList));
    if (!pktl)
        return NULL;

    if (*packet_buffer)
        (*plast_pktl)->next = pktl;
    else
        *packet_buffer = pktl;

    /* add the packet in the buffered packet list */
    *plast_pktl = pktl;
    pktl->pkt= *pkt;
    return &pktl->pkt;
}

int av_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    int ret, i;
    AVStream *st;

    for(;;){
        AVPacketList *pktl = s->raw_packet_buffer;

        if (pktl) {
            *pkt = pktl->pkt;
            if(s->streams[pkt->stream_index]->codec->codec_id != CODEC_ID_PROBE ||
               !s->streams[pkt->stream_index]->probe_packets ||
               s->raw_packet_buffer_remaining_size < pkt->size){
                AVProbeData *pd = &s->streams[pkt->stream_index]->probe_data;
                av_freep(&pd->buf);
                pd->buf_size = 0;
                s->raw_packet_buffer = pktl->next;
                s->raw_packet_buffer_remaining_size += pkt->size;
                av_free(pktl);
                return 0;
            }
        }

        av_init_packet(pkt);
        ret= s->iformat->read_packet(s, pkt);
        if (ret < 0) {
            if (!pktl || ret == AVERROR(EAGAIN))
                return ret;
            for (i = 0; i < s->nb_streams; i++)
                s->streams[i]->probe_packets = 0;
            continue;
        }
        st= s->streams[pkt->stream_index];

        switch(st->codec->codec_type){
        case AVMEDIA_TYPE_VIDEO:
            if(s->video_codec_id)   st->codec->codec_id= s->video_codec_id;
            break;
        case AVMEDIA_TYPE_AUDIO:
            if(s->audio_codec_id)   st->codec->codec_id= s->audio_codec_id;
            break;
        case AVMEDIA_TYPE_SUBTITLE:
            if(s->subtitle_codec_id)st->codec->codec_id= s->subtitle_codec_id;
            break;
        }

        if(!pktl && (st->codec->codec_id != CODEC_ID_PROBE ||
                     !st->probe_packets))
            return ret;

        add_to_pktbuf(&s->raw_packet_buffer, pkt, &s->raw_packet_buffer_end);
        s->raw_packet_buffer_remaining_size -= pkt->size;

        if(st->codec->codec_id == CODEC_ID_PROBE){
            AVProbeData *pd = &st->probe_data;
            av_log(s, AV_LOG_DEBUG, "probing stream %d\n", st->index);
            --st->probe_packets;

            pd->buf = av_realloc(pd->buf, pd->buf_size+pkt->size+AVPROBE_PADDING_SIZE);
            memcpy(pd->buf+pd->buf_size, pkt->data, pkt->size);
            pd->buf_size += pkt->size;
            memset(pd->buf+pd->buf_size, 0, AVPROBE_PADDING_SIZE);

            if(av_log2(pd->buf_size) != av_log2(pd->buf_size - pkt->size)){
                //FIXME we dont reduce score to 0 for the case of running out of buffer space in bytes
                set_codec_from_probe_data(s, st, pd, st->probe_packets > 0 ? AVPROBE_SCORE_MAX/4 : 0);
                if(st->codec->codec_id != CODEC_ID_PROBE){
                    pd->buf_size=0;
                    av_freep(&pd->buf);
                    av_log(s, AV_LOG_DEBUG, "probed stream %d\n", st->index);
                }
            }
        }
    }
}

/**********************************************************/

/**
 * Get the number of samples of an audio frame. Return -1 on error.
 */
static int get_audio_frame_size(AVCodecContext *enc, int size)
{
    int frame_size;

    if(enc->codec_id == CODEC_ID_VORBIS)
        return -1;

    if (enc->frame_size <= 1) {
        int bits_per_sample = av_get_bits_per_sample(enc->codec_id);

        if (bits_per_sample) {
            if (enc->channels == 0)
                return -1;
            frame_size = (size << 3) / (bits_per_sample * enc->channels);
        } else {
            /* used for example by ADPCM codecs */
            if (enc->bit_rate == 0)
                return -1;
            frame_size = ((int64_t)size * 8 * enc->sample_rate) / enc->bit_rate;
        }
    } else {
        frame_size = enc->frame_size;
    }
    return frame_size;
}


/**
 * Return the frame duration in seconds. Return 0 if not available.
 */
static void compute_frame_duration(int *pnum, int *pden, AVStream *st,
                                   AVCodecParserContext *pc, AVPacket *pkt)
{
    int frame_size;

    *pnum = 0;
    *pden = 0;
    switch(st->codec->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        if(st->time_base.num*1000LL > st->time_base.den){
            *pnum = st->time_base.num;
            *pden = st->time_base.den;
        }else if(st->codec->time_base.num*1000LL > st->codec->time_base.den){
            *pnum = st->codec->time_base.num;
            *pden = st->codec->time_base.den;
            if (pc && pc->repeat_pict) {
                *pnum = (*pnum) * (1 + pc->repeat_pict);
            }
            //If this codec can be interlaced or progressive then we need a parser to compute duration of a packet
            //Thus if we have no parser in such case leave duration undefined.
            if(st->codec->ticks_per_frame>1 && !pc){
                *pnum = *pden = 0;
            }
        }
        break;
    case AVMEDIA_TYPE_AUDIO:
        frame_size = get_audio_frame_size(st->codec, pkt->size);
        if (frame_size < 0)
            break;
        *pnum = frame_size;
        *pden = st->codec->sample_rate;
        break;
    default:
        break;
    }
}

static int is_intra_only(AVCodecContext *enc){
    if(enc->codec_type == AVMEDIA_TYPE_AUDIO){
        return 1;
    }else if(enc->codec_type == AVMEDIA_TYPE_VIDEO){
        switch(enc->codec_id){
        case CODEC_ID_MJPEG:
        case CODEC_ID_MJPEGB:
        case CODEC_ID_LJPEG:
        case CODEC_ID_RAWVIDEO:
        case CODEC_ID_DVVIDEO:
        case CODEC_ID_HUFFYUV:
        case CODEC_ID_FFVHUFF:
        case CODEC_ID_ASV1:
        case CODEC_ID_ASV2:
        case CODEC_ID_VCR1:
        case CODEC_ID_DNXHD:
        case CODEC_ID_JPEG2000:
            return 1;
        default: break;
        }
    }
    return 0;
}

static void update_initial_timestamps(AVFormatContext *s, int stream_index,
                                      int64_t dts, int64_t pts)
{
    AVStream *st= s->streams[stream_index];
    AVPacketList *pktl= s->packet_buffer;

    if(st->first_dts != AV_NOPTS_VALUE || dts == AV_NOPTS_VALUE || st->cur_dts == AV_NOPTS_VALUE)
        return;

    st->first_dts= dts - st->cur_dts;
    st->cur_dts= dts;

    for(; pktl; pktl= pktl->next){
        if(pktl->pkt.stream_index != stream_index)
            continue;
        //FIXME think more about this check
        if(pktl->pkt.pts != AV_NOPTS_VALUE && pktl->pkt.pts == pktl->pkt.dts)
            pktl->pkt.pts += st->first_dts;

        if(pktl->pkt.dts != AV_NOPTS_VALUE)
            pktl->pkt.dts += st->first_dts;

        if(st->start_time == AV_NOPTS_VALUE && pktl->pkt.pts != AV_NOPTS_VALUE)
            st->start_time= pktl->pkt.pts;
    }
    if (st->start_time == AV_NOPTS_VALUE)
        st->start_time = pts;
}

static void update_initial_durations(AVFormatContext *s, AVStream *st, AVPacket *pkt)
{
    AVPacketList *pktl= s->packet_buffer;
    int64_t cur_dts= 0;

    if(st->first_dts != AV_NOPTS_VALUE){
        cur_dts= st->first_dts;
        for(; pktl; pktl= pktl->next){
            if(pktl->pkt.stream_index == pkt->stream_index){
                if(pktl->pkt.pts != pktl->pkt.dts || pktl->pkt.dts != AV_NOPTS_VALUE || pktl->pkt.duration)
                    break;
                cur_dts -= pkt->duration;
            }
        }
        pktl= s->packet_buffer;
        st->first_dts = cur_dts;
    }else if(st->cur_dts)
        return;

    for(; pktl; pktl= pktl->next){
        if(pktl->pkt.stream_index != pkt->stream_index)
            continue;
        if(pktl->pkt.pts == pktl->pkt.dts && pktl->pkt.dts == AV_NOPTS_VALUE
           && !pktl->pkt.duration){
            pktl->pkt.dts= cur_dts;
            if(!st->codec->has_b_frames)
                pktl->pkt.pts= cur_dts;
            cur_dts += pkt->duration;
            pktl->pkt.duration= pkt->duration;
        }else
            break;
    }
    if(st->first_dts == AV_NOPTS_VALUE)
        st->cur_dts= cur_dts;
}

static void compute_pkt_fields(AVFormatContext *s, AVStream *st,
                               AVCodecParserContext *pc, AVPacket *pkt)
{
    int num, den, presentation_delayed, delay, i;
    int64_t offset;

    if (s->flags & AVFMT_FLAG_NOFILLIN)
        return;

    if((s->flags & AVFMT_FLAG_IGNDTS) && pkt->pts != AV_NOPTS_VALUE)
        pkt->dts= AV_NOPTS_VALUE;

    if (st->codec->codec_id != CODEC_ID_H264 && pc && pc->pict_type == FF_B_TYPE)
        //FIXME Set low_delay = 0 when has_b_frames = 1
        st->codec->has_b_frames = 1;

    /* do we have a video B-frame ? */
    delay= st->codec->has_b_frames;
    presentation_delayed = 0;
    /* XXX: need has_b_frame, but cannot get it if the codec is
        not initialized */
    if (delay &&
        pc && pc->pict_type != FF_B_TYPE)
        presentation_delayed = 1;

    if(pkt->pts != AV_NOPTS_VALUE && pkt->dts != AV_NOPTS_VALUE && pkt->dts > pkt->pts && st->pts_wrap_bits<63
       /*&& pkt->dts-(1LL<<st->pts_wrap_bits) < pkt->pts*/){
        pkt->dts -= 1LL<<st->pts_wrap_bits;
    }

    // some mpeg2 in mpeg-ps lack dts (issue171 / input_file.mpg)
    // we take the conservative approach and discard both
    // Note, if this is misbehaving for a H.264 file then possibly presentation_delayed is not set correctly.
    if(delay==1 && pkt->dts == pkt->pts && pkt->dts != AV_NOPTS_VALUE && presentation_delayed){
        av_log(s, AV_LOG_WARNING, "invalid dts/pts combination\n");
        pkt->dts= pkt->pts= AV_NOPTS_VALUE;
    }

    if (pkt->duration == 0) {
        compute_frame_duration(&num, &den, st, pc, pkt);
        if (den && num) {
            pkt->duration = av_rescale_rnd(1, num * (int64_t)st->time_base.den, den * (int64_t)st->time_base.num, AV_ROUND_DOWN);

            if(pkt->duration != 0 && s->packet_buffer)
                update_initial_durations(s, st, pkt);
        }
    }

    /* correct timestamps with byte offset if demuxers only have timestamps
       on packet boundaries */
    if(pc && st->need_parsing == AVSTREAM_PARSE_TIMESTAMPS && pkt->size){
        /* this will estimate bitrate based on this frame's duration and size */
        offset = av_rescale(pc->offset, pkt->duration, pkt->size);
        if(pkt->pts != AV_NOPTS_VALUE)
            pkt->pts += offset;
        if(pkt->dts != AV_NOPTS_VALUE)
            pkt->dts += offset;
    }

    if (pc && pc->dts_sync_point >= 0) {
        // we have synchronization info from the parser
        int64_t den = st->codec->time_base.den * (int64_t) st->time_base.num;
        if (den > 0) {
            int64_t num = st->codec->time_base.num * (int64_t) st->time_base.den;
            if (pkt->dts != AV_NOPTS_VALUE) {
                // got DTS from the stream, update reference timestamp
                st->reference_dts = pkt->dts - pc->dts_ref_dts_delta * num / den;
                pkt->pts = pkt->dts + pc->pts_dts_delta * num / den;
            } else if (st->reference_dts != AV_NOPTS_VALUE) {
                // compute DTS based on reference timestamp
                pkt->dts = st->reference_dts + pc->dts_ref_dts_delta * num / den;
                pkt->pts = pkt->dts + pc->pts_dts_delta * num / den;
            }
            if (pc->dts_sync_point > 0)
                st->reference_dts = pkt->dts; // new reference
        }
    }

    /* This may be redundant, but it should not hurt. */
    if(pkt->dts != AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE && pkt->pts > pkt->dts)
        presentation_delayed = 1;

//    av_log(NULL, AV_LOG_DEBUG, "IN delayed:%d pts:%"PRId64", dts:%"PRId64" cur_dts:%"PRId64" st:%d pc:%p\n", presentation_delayed, pkt->pts, pkt->dts, st->cur_dts, pkt->stream_index, pc);
    /* interpolate PTS and DTS if they are not present */
    //We skip H264 currently because delay and has_b_frames are not reliably set
    if((delay==0 || (delay==1 && pc)) && st->codec->codec_id != CODEC_ID_H264){
        if (presentation_delayed) {
            /* DTS = decompression timestamp */
            /* PTS = presentation timestamp */
            if (pkt->dts == AV_NOPTS_VALUE)
                pkt->dts = st->last_IP_pts;
            update_initial_timestamps(s, pkt->stream_index, pkt->dts, pkt->pts);
            if (pkt->dts == AV_NOPTS_VALUE)
                pkt->dts = st->cur_dts;

            /* this is tricky: the dts must be incremented by the duration
            of the frame we are displaying, i.e. the last I- or P-frame */
            if (st->last_IP_duration == 0)
                st->last_IP_duration = pkt->duration;
            if(pkt->dts != AV_NOPTS_VALUE)
                st->cur_dts = pkt->dts + st->last_IP_duration;
            st->last_IP_duration  = pkt->duration;
            st->last_IP_pts= pkt->pts;
            /* cannot compute PTS if not present (we can compute it only
            by knowing the future */
        } else if(pkt->pts != AV_NOPTS_VALUE || pkt->dts != AV_NOPTS_VALUE || pkt->duration){
            if(pkt->pts != AV_NOPTS_VALUE && pkt->duration){
                int64_t old_diff= FFABS(st->cur_dts - pkt->duration - pkt->pts);
                int64_t new_diff= FFABS(st->cur_dts - pkt->pts);
                if(old_diff < new_diff && old_diff < (pkt->duration>>3)){
                    pkt->pts += pkt->duration;
    //                av_log(NULL, AV_LOG_DEBUG, "id:%d old:%"PRId64" new:%"PRId64" dur:%d cur:%"PRId64" size:%d\n", pkt->stream_index, old_diff, new_diff, pkt->duration, st->cur_dts, pkt->size);
                }
            }

            /* presentation is not delayed : PTS and DTS are the same */
            if(pkt->pts == AV_NOPTS_VALUE)
                pkt->pts = pkt->dts;
            update_initial_timestamps(s, pkt->stream_index, pkt->pts, pkt->pts);
            if(pkt->pts == AV_NOPTS_VALUE)
                pkt->pts = st->cur_dts;
            pkt->dts = pkt->pts;
            if(pkt->pts != AV_NOPTS_VALUE)
                st->cur_dts = pkt->pts + pkt->duration;
        }
    }

    if(pkt->pts != AV_NOPTS_VALUE && delay <= MAX_REORDER_DELAY){
        st->pts_buffer[0]= pkt->pts;
        for(i=0; i<delay && st->pts_buffer[i] > st->pts_buffer[i+1]; i++)
            FFSWAP(int64_t, st->pts_buffer[i], st->pts_buffer[i+1]);
        if(pkt->dts == AV_NOPTS_VALUE)
            pkt->dts= st->pts_buffer[0];
        if(st->codec->codec_id == CODEC_ID_H264){ //we skiped it above so we try here
            update_initial_timestamps(s, pkt->stream_index, pkt->dts, pkt->pts); // this should happen on the first packet
        }
        if(pkt->dts > st->cur_dts)
            st->cur_dts = pkt->dts;
    }

//    av_log(NULL, AV_LOG_ERROR, "OUTdelayed:%d/%d pts:%"PRId64", dts:%"PRId64" cur_dts:%"PRId64"\n", presentation_delayed, delay, pkt->pts, pkt->dts, st->cur_dts);

    /* update flags */
    if(is_intra_only(st->codec))
        pkt->flags |= AV_PKT_FLAG_KEY;
    else if (pc) {
        pkt->flags = 0;
        /* keyframe computation */
        if (pc->key_frame == 1)
            pkt->flags |= AV_PKT_FLAG_KEY;
        else if (pc->key_frame == -1 && pc->pict_type == FF_I_TYPE)
            pkt->flags |= AV_PKT_FLAG_KEY;
    }
    if (pc)
        pkt->convergence_duration = pc->convergence_duration;
}


static int av_read_frame_internal(AVFormatContext *s, AVPacket *pkt)
{
    AVStream *st;
    int len, ret, i;

    av_init_packet(pkt);

    for(;;) {
        /* select current input stream component */
        st = s->cur_st;
        if (st) {
            if (!st->need_parsing || !st->parser) {
                /* no parsing needed: we just output the packet as is */
                /* raw data support */
                *pkt = st->cur_pkt; st->cur_pkt.data= NULL;
                compute_pkt_fields(s, st, NULL, pkt);
                s->cur_st = NULL;
                if ((s->iformat->flags & AVFMT_GENERIC_INDEX) &&
                    (pkt->flags & AV_PKT_FLAG_KEY) && pkt->dts != AV_NOPTS_VALUE) {
                    ff_reduce_index(s, st->index);
                    av_add_index_entry(st, pkt->pos, pkt->dts, 0, 0, AVINDEX_KEYFRAME);
                }
                break;
            } else if (st->cur_len > 0 && st->discard < AVDISCARD_ALL) {
                len = av_parser_parse2(st->parser, st->codec, &pkt->data, &pkt->size,
                                       st->cur_ptr, st->cur_len,
                                       st->cur_pkt.pts, st->cur_pkt.dts,
                                       st->cur_pkt.pos);
                st->cur_pkt.pts = AV_NOPTS_VALUE;
                st->cur_pkt.dts = AV_NOPTS_VALUE;
                /* increment read pointer */
                st->cur_ptr += len;
                st->cur_len -= len;

                /* return packet if any */
                if (pkt->size) {
                got_packet:
                    pkt->duration = 0;
                    pkt->stream_index = st->index;
                    pkt->pts = st->parser->pts;
                    pkt->dts = st->parser->dts;
                    pkt->pos = st->parser->pos;
                    pkt->destruct = NULL;
                    compute_pkt_fields(s, st, st->parser, pkt);

                    if((s->iformat->flags & AVFMT_GENERIC_INDEX) && pkt->flags & AV_PKT_FLAG_KEY){
                        ff_reduce_index(s, st->index);
                        av_add_index_entry(st, st->parser->frame_offset, pkt->dts,
                                           0, 0, AVINDEX_KEYFRAME);
                    }

                    break;
                }
            } else {
                /* free packet */
                av_free_packet(&st->cur_pkt);
                s->cur_st = NULL;
            }
        } else {
            AVPacket cur_pkt;
            /* read next packet */
            ret = av_read_packet(s, &cur_pkt);
            if (ret < 0) {
                if (ret == AVERROR(EAGAIN))
                    return ret;
                /* return the last frames, if any */
                for(i = 0; i < s->nb_streams; i++) {
                    st = s->streams[i];
                    if (st->parser && st->need_parsing) {
                        av_parser_parse2(st->parser, st->codec,
                                        &pkt->data, &pkt->size,
                                        NULL, 0,
                                        AV_NOPTS_VALUE, AV_NOPTS_VALUE,
                                        AV_NOPTS_VALUE);
                        if (pkt->size)
                            goto got_packet;
                    }
                }
                /* no more packets: really terminate parsing */
                return ret;
            }
            st = s->streams[cur_pkt.stream_index];
            st->cur_pkt= cur_pkt;

            if(st->cur_pkt.pts != AV_NOPTS_VALUE &&
               st->cur_pkt.dts != AV_NOPTS_VALUE &&
               st->cur_pkt.pts < st->cur_pkt.dts){
                av_log(s, AV_LOG_WARNING, "Invalid timestamps stream=%d, pts=%"PRId64", dts=%"PRId64", size=%d\n",
                    st->cur_pkt.stream_index,
                    st->cur_pkt.pts,
                    st->cur_pkt.dts,
                    st->cur_pkt.size);
//                av_free_packet(&st->cur_pkt);
//                return -1;
            }

            if(s->debug & FF_FDEBUG_TS)
                av_log(s, AV_LOG_DEBUG, "av_read_packet stream=%d, pts=%"PRId64", dts=%"PRId64", size=%d, duration=%d, flags=%d\n",
                    st->cur_pkt.stream_index,
                    st->cur_pkt.pts,
                    st->cur_pkt.dts,
                    st->cur_pkt.size,
                    st->cur_pkt.duration,
                    st->cur_pkt.flags);

            s->cur_st = st;
            st->cur_ptr = st->cur_pkt.data;
            st->cur_len = st->cur_pkt.size;
            if (st->need_parsing && !st->parser && !(s->flags & AVFMT_FLAG_NOPARSE)) {
                st->parser = av_parser_init(st->codec->codec_id);
                if (!st->parser) {
                    /* no parser available: just output the raw packets */
                    st->need_parsing = AVSTREAM_PARSE_NONE;
                }else if(st->need_parsing == AVSTREAM_PARSE_HEADERS){
                    st->parser->flags |= PARSER_FLAG_COMPLETE_FRAMES;
                }
                if(st->parser && (s->iformat->flags & AVFMT_GENERIC_INDEX)){
                    st->parser->next_frame_offset=
                    st->parser->cur_offset= st->cur_pkt.pos;
                }
            }
        }
    }
    if(s->debug & FF_FDEBUG_TS)
        av_log(s, AV_LOG_DEBUG, "av_read_frame_internal stream=%d, pts=%"PRId64", dts=%"PRId64", size=%d, duration=%d, flags=%d\n",
            pkt->stream_index,
            pkt->pts,
            pkt->dts,
            pkt->size,
            pkt->duration,
            pkt->flags);

    return 0;
}

int av_read_frame(AVFormatContext *s, AVPacket *pkt)
{
    AVPacketList *pktl;
    int eof=0;
    const int genpts= s->flags & AVFMT_FLAG_GENPTS;

    for(;;){
        pktl = s->packet_buffer;
        if (pktl) {
            AVPacket *next_pkt= &pktl->pkt;

            if(genpts && next_pkt->dts != AV_NOPTS_VALUE){
                while(pktl && next_pkt->pts == AV_NOPTS_VALUE){
                    if(   pktl->pkt.stream_index == next_pkt->stream_index
                       && next_pkt->dts < pktl->pkt.dts
                       && pktl->pkt.pts != pktl->pkt.dts //not b frame
                       /*&& pktl->pkt.dts != AV_NOPTS_VALUE*/){
                        next_pkt->pts= pktl->pkt.dts;
                    }
                    pktl= pktl->next;
                }
                pktl = s->packet_buffer;
            }

            if(   next_pkt->pts != AV_NOPTS_VALUE
               || next_pkt->dts == AV_NOPTS_VALUE
               || !genpts || eof){
                /* read packet from packet buffer, if there is data */
                *pkt = *next_pkt;
                s->packet_buffer = pktl->next;
                av_free(pktl);
                return 0;
            }
        }
        if(genpts){
            int ret= av_read_frame_internal(s, pkt);
            if(ret<0){
                if(pktl && ret != AVERROR(EAGAIN)){
                    eof=1;
                    continue;
                }else
                    return ret;
            }

            if(av_dup_packet(add_to_pktbuf(&s->packet_buffer, pkt,
                                           &s->packet_buffer_end)) < 0)
                return AVERROR(ENOMEM);
        }else{
            assert(!s->packet_buffer);
            return av_read_frame_internal(s, pkt);
        }
    }
}

/* XXX: suppress the packet queue */
static void flush_packet_queue(AVFormatContext *s)
{
    AVPacketList *pktl;

    for(;;) {
        pktl = s->packet_buffer;
        if (!pktl)
            break;
        s->packet_buffer = pktl->next;
        av_free_packet(&pktl->pkt);
        av_free(pktl);
    }
    while(s->raw_packet_buffer){
        pktl = s->raw_packet_buffer;
        s->raw_packet_buffer = pktl->next;
        av_free_packet(&pktl->pkt);
        av_free(pktl);
    }
    s->packet_buffer_end=
    s->raw_packet_buffer_end= NULL;
    s->raw_packet_buffer_remaining_size = RAW_PACKET_BUFFER_SIZE;
}

/*******************************************************/
/* seek support */

int av_find_default_stream_index(AVFormatContext *s)
{
    int first_audio_index = -1;
    int i;
    AVStream *st;

    if (s->nb_streams <= 0)
        return -1;
    for(i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
            return i;
        }
        if (first_audio_index < 0 && st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
            first_audio_index = i;
    }
    return first_audio_index >= 0 ? first_audio_index : 0;
}

/**
 * Flush the frame reader.
 */
void ff_read_frame_flush(AVFormatContext *s)
{
    AVStream *st;
    int i, j;

    flush_packet_queue(s);

    s->cur_st = NULL;

    /* for each stream, reset read state */
    for(i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];

        if (st->parser) {
            av_parser_close(st->parser);
            st->parser = NULL;
            av_free_packet(&st->cur_pkt);
        }
        st->last_IP_pts = AV_NOPTS_VALUE;
        st->cur_dts = AV_NOPTS_VALUE; /* we set the current DTS to an unspecified origin */
        st->reference_dts = AV_NOPTS_VALUE;
        /* fail safe */
        st->cur_ptr = NULL;
        st->cur_len = 0;

        st->probe_packets = MAX_PROBE_PACKETS;

        for(j=0; j<MAX_REORDER_DELAY+1; j++)
            st->pts_buffer[j]= AV_NOPTS_VALUE;
    }
}

void av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp){
    int i;

    for(i = 0; i < s->nb_streams; i++) {
        AVStream *st = s->streams[i];

        st->cur_dts = av_rescale(timestamp,
                                 st->time_base.den * (int64_t)ref_st->time_base.num,
                                 st->time_base.num * (int64_t)ref_st->time_base.den);
    }
}

void ff_reduce_index(AVFormatContext *s, int stream_index)
{
    AVStream *st= s->streams[stream_index];
    unsigned int max_entries= s->max_index_size / sizeof(AVIndexEntry);

    if((unsigned)st->nb_index_entries >= max_entries){
        int i;
        for(i=0; 2*i<st->nb_index_entries; i++)
            st->index_entries[i]= st->index_entries[2*i];
        st->nb_index_entries= i;
    }
}

int av_add_index_entry(AVStream *st,
                            int64_t pos, int64_t timestamp, int size, int distance, int flags)
{
    AVIndexEntry *entries, *ie;
    int index;

    if((unsigned)st->nb_index_entries + 1 >= UINT_MAX / sizeof(AVIndexEntry))
        return -1;

    entries = av_fast_realloc(st->index_entries,
                              &st->index_entries_allocated_size,
                              (st->nb_index_entries + 1) *
                              sizeof(AVIndexEntry));
    if(!entries)
        return -1;

    st->index_entries= entries;

    index= av_index_search_timestamp(st, timestamp, AVSEEK_FLAG_ANY);

    if(index<0){
        index= st->nb_index_entries++;
        ie= &entries[index];
        assert(index==0 || ie[-1].timestamp < timestamp);
    }else{
        ie= &entries[index];
        if(ie->timestamp != timestamp){
            if(ie->timestamp <= timestamp)
                return -1;
            memmove(entries + index + 1, entries + index, sizeof(AVIndexEntry)*(st->nb_index_entries - index));
            st->nb_index_entries++;
        }else if(ie->pos == pos && distance < ie->min_distance) //do not reduce the distance
            distance= ie->min_distance;
    }

    ie->pos = pos;
    ie->timestamp = timestamp;
    ie->min_distance= distance;
    ie->size= size;
    ie->flags = flags;

    return index;
}

int av_index_search_timestamp(AVStream *st, int64_t wanted_timestamp,
                              int flags)
{
    AVIndexEntry *entries= st->index_entries;
    int nb_entries= st->nb_index_entries;
    int a, b, m;
    int64_t timestamp;

    a = - 1;
    b = nb_entries;

    //optimize appending index entries at the end
    if(b && entries[b-1].timestamp < wanted_timestamp)
        a= b-1;

    while (b - a > 1) {
        m = (a + b) >> 1;
        timestamp = entries[m].timestamp;
        if(timestamp >= wanted_timestamp)
            b = m;
        if(timestamp <= wanted_timestamp)
            a = m;
    }
    m= (flags & AVSEEK_FLAG_BACKWARD) ? a : b;

    if(!(flags & AVSEEK_FLAG_ANY)){
        while(m>=0 && m<nb_entries && !(entries[m].flags & AVINDEX_KEYFRAME)){
            m += (flags & AVSEEK_FLAG_BACKWARD) ? -1 : 1;
        }
    }

    if(m == nb_entries)
        return -1;
    return  m;
}

#define DEBUG_SEEK

int av_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags){
    AVInputFormat *avif= s->iformat;
    int64_t av_uninit(pos_min), av_uninit(pos_max), pos, pos_limit;
    int64_t ts_min, ts_max, ts;
    int index;
    int64_t ret;
    AVStream *st;

    if (stream_index < 0)
        return -1;

#ifdef DEBUG_SEEK
    av_log(s, AV_LOG_DEBUG, "read_seek: %d %"PRId64"\n", stream_index, target_ts);
#endif

    ts_max=
    ts_min= AV_NOPTS_VALUE;
    pos_limit= -1; //gcc falsely says it may be uninitialized

    st= s->streams[stream_index];
    if(st->index_entries){
        AVIndexEntry *e;

        index= av_index_search_timestamp(st, target_ts, flags | AVSEEK_FLAG_BACKWARD); //FIXME whole func must be checked for non-keyframe entries in index case, especially read_timestamp()
        index= FFMAX(index, 0);
        e= &st->index_entries[index];

        if(e->timestamp <= target_ts || e->pos == e->min_distance){
            pos_min= e->pos;
            ts_min= e->timestamp;
#ifdef DEBUG_SEEK
            av_log(s, AV_LOG_DEBUG, "using cached pos_min=0x%"PRIx64" dts_min=%"PRId64"\n",
                   pos_min,ts_min);
#endif
        }else{
            assert(index==0);
        }

        index= av_index_search_timestamp(st, target_ts, flags & ~AVSEEK_FLAG_BACKWARD);
        assert(index < st->nb_index_entries);
        if(index >= 0){
            e= &st->index_entries[index];
            assert(e->timestamp >= target_ts);
            pos_max= e->pos;
            ts_max= e->timestamp;
            pos_limit= pos_max - e->min_distance;
#ifdef DEBUG_SEEK
            av_log(s, AV_LOG_DEBUG, "using cached pos_max=0x%"PRIx64" pos_limit=0x%"PRIx64" dts_max=%"PRId64"\n",
                   pos_max,pos_limit, ts_max);
#endif
        }
    }

    pos= av_gen_search(s, stream_index, target_ts, pos_min, pos_max, pos_limit, ts_min, ts_max, flags, &ts, avif->read_timestamp);
    if(pos<0)
        return -1;

    /* do the seek */
    if ((ret = url_fseek(s->pb, pos, SEEK_SET)) < 0)
        return ret;

    av_update_cur_dts(s, st, ts);

    return 0;
}

int64_t av_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts, int64_t pos_min, int64_t pos_max, int64_t pos_limit, int64_t ts_min, int64_t ts_max, int flags, int64_t *ts_ret, int64_t (*read_timestamp)(struct AVFormatContext *, int , int64_t *, int64_t )){
    int64_t pos, ts;
    int64_t start_pos, filesize;
    int no_change;

#ifdef DEBUG_SEEK
    av_log(s, AV_LOG_DEBUG, "gen_seek: %d %"PRId64"\n", stream_index, target_ts);
#endif

    if(ts_min == AV_NOPTS_VALUE){
        pos_min = s->data_offset;
        ts_min = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
        if (ts_min == AV_NOPTS_VALUE)
            return -1;
    }

    if(ts_max == AV_NOPTS_VALUE){
        int step= 1024;
        filesize = url_fsize(s->pb);
        pos_max = filesize - 1;
        do{
            pos_max -= step;
            ts_max = read_timestamp(s, stream_index, &pos_max, pos_max + step);
            step += step;
        }while(ts_max == AV_NOPTS_VALUE && pos_max >= step);
        if (ts_max == AV_NOPTS_VALUE)
            return -1;

        for(;;){
            int64_t tmp_pos= pos_max + 1;
            int64_t tmp_ts= read_timestamp(s, stream_index, &tmp_pos, INT64_MAX);
            if(tmp_ts == AV_NOPTS_VALUE)
                break;
            ts_max= tmp_ts;
            pos_max= tmp_pos;
            if(tmp_pos >= filesize)
                break;
        }
        pos_limit= pos_max;
    }

    if(ts_min > ts_max){
        return -1;
    }else if(ts_min == ts_max){
        pos_limit= pos_min;
    }

    no_change=0;
    while (pos_min < pos_limit) {
#ifdef DEBUG_SEEK
        av_log(s, AV_LOG_DEBUG, "pos_min=0x%"PRIx64" pos_max=0x%"PRIx64" dts_min=%"PRId64" dts_max=%"PRId64"\n",
               pos_min, pos_max,
               ts_min, ts_max);
#endif
        assert(pos_limit <= pos_max);

        if(no_change==0){
            int64_t approximate_keyframe_distance= pos_max - pos_limit;
            // interpolate position (better than dichotomy)
            pos = av_rescale(target_ts - ts_min, pos_max - pos_min, ts_max - ts_min)
                + pos_min - approximate_keyframe_distance;
        }else if(no_change==1){
            // bisection, if interpolation failed to change min or max pos last time
            pos = (pos_min + pos_limit)>>1;
        }else{
            /* linear search if bisection failed, can only happen if there
               are very few or no keyframes between min/max */
            pos=pos_min;
        }
        if(pos <= pos_min)
            pos= pos_min + 1;
        else if(pos > pos_limit)
            pos= pos_limit;
        start_pos= pos;

        ts = read_timestamp(s, stream_index, &pos, INT64_MAX); //may pass pos_limit instead of -1
        if(pos == pos_max)
            no_change++;
        else
            no_change=0;
#ifdef DEBUG_SEEK
        av_log(s, AV_LOG_DEBUG, "%"PRId64" %"PRId64" %"PRId64" / %"PRId64" %"PRId64" %"PRId64" target:%"PRId64" limit:%"PRId64" start:%"PRId64" noc:%d\n",
               pos_min, pos, pos_max, ts_min, ts, ts_max, target_ts, pos_limit,
               start_pos, no_change);
#endif
        if(ts == AV_NOPTS_VALUE){
            av_log(s, AV_LOG_ERROR, "read_timestamp() failed in the middle\n");
            return -1;
        }
        assert(ts != AV_NOPTS_VALUE);
        if (target_ts <= ts) {
            pos_limit = start_pos - 1;
            pos_max = pos;
            ts_max = ts;
        }
        if (target_ts >= ts) {
            pos_min = pos;
            ts_min = ts;
        }
    }

    pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
    ts  = (flags & AVSEEK_FLAG_BACKWARD) ?  ts_min :  ts_max;
#ifdef DEBUG_SEEK
    pos_min = pos;
    ts_min = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
    pos_min++;
    ts_max = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
    av_log(s, AV_LOG_DEBUG, "pos=0x%"PRIx64" %"PRId64"<=%"PRId64"<=%"PRId64"\n",
           pos, ts_min, target_ts, ts_max);
#endif
    *ts_ret= ts;
    return pos;
}

static int av_seek_frame_byte(AVFormatContext *s, int stream_index, int64_t pos, int flags){
    int64_t pos_min, pos_max;
#if 0
    AVStream *st;

    if (stream_index < 0)
        return -1;

    st= s->streams[stream_index];
#endif

    pos_min = s->data_offset;
    pos_max = url_fsize(s->pb) - 1;

    if     (pos < pos_min) pos= pos_min;
    else if(pos > pos_max) pos= pos_max;

    url_fseek(s->pb, pos, SEEK_SET);

#if 0
    av_update_cur_dts(s, st, ts);
#endif
    return 0;
}

static int av_seek_frame_generic(AVFormatContext *s,
                                 int stream_index, int64_t timestamp, int flags)
{
    int index;
    int64_t ret;
    AVStream *st;
    AVIndexEntry *ie;

    st = s->streams[stream_index];

    index = av_index_search_timestamp(st, timestamp, flags);

    if(index < 0 && st->nb_index_entries && timestamp < st->index_entries[0].timestamp)
        return -1;

    if(index < 0 || index==st->nb_index_entries-1){
        int i;
        AVPacket pkt;

        if(st->nb_index_entries){
            assert(st->index_entries);
            ie= &st->index_entries[st->nb_index_entries-1];
            if ((ret = url_fseek(s->pb, ie->pos, SEEK_SET)) < 0)
                return ret;
            av_update_cur_dts(s, st, ie->timestamp);
        }else{
            if ((ret = url_fseek(s->pb, s->data_offset, SEEK_SET)) < 0)
                return ret;
        }
        for(i=0;; i++) {
            int ret;
            do{
                ret = av_read_frame(s, &pkt);
            }while(ret == AVERROR(EAGAIN));
            if(ret<0)
                break;
            av_free_packet(&pkt);
            if(stream_index == pkt.stream_index){
                if((pkt.flags & AV_PKT_FLAG_KEY) && pkt.dts > timestamp)
                    break;
            }
        }
        index = av_index_search_timestamp(st, timestamp, flags);
    }
    if (index < 0)
        return -1;

    ff_read_frame_flush(s);
    if (s->iformat->read_seek){
        if(s->iformat->read_seek(s, stream_index, timestamp, flags) >= 0)
            return 0;
    }
    ie = &st->index_entries[index];
    if ((ret = url_fseek(s->pb, ie->pos, SEEK_SET)) < 0)
        return ret;
    av_update_cur_dts(s, st, ie->timestamp);

    return 0;
}

int av_seek_frame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
    int ret;
    AVStream *st;

    ff_read_frame_flush(s);

    if(flags & AVSEEK_FLAG_BYTE)
        return av_seek_frame_byte(s, stream_index, timestamp, flags);

    if(stream_index < 0){
        stream_index= av_find_default_stream_index(s);
        if(stream_index < 0)
            return -1;

        st= s->streams[stream_index];
       /* timestamp for default must be expressed in AV_TIME_BASE units */
        timestamp = av_rescale(timestamp, st->time_base.den, AV_TIME_BASE * (int64_t)st->time_base.num);
    }

    /* first, we try the format specific seek */
    if (s->iformat->read_seek)
        ret = s->iformat->read_seek(s, stream_index, timestamp, flags);
    else
        ret = -1;
    if (ret >= 0) {
        return 0;
    }

    if(s->iformat->read_timestamp)
        return av_seek_frame_binary(s, stream_index, timestamp, flags);
    else
        return av_seek_frame_generic(s, stream_index, timestamp, flags);
}

int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
{
    if(min_ts > ts || max_ts < ts)
        return -1;

    ff_read_frame_flush(s);

    if (s->iformat->read_seek2)
        return s->iformat->read_seek2(s, stream_index, min_ts, ts, max_ts, flags);

    if(s->iformat->read_timestamp){
        //try to seek via read_timestamp()
    }

    //Fallback to old API if new is not implemented but old is
    //Note the old has somewat different sematics
    if(s->iformat->read_seek || 1)
        return av_seek_frame(s, stream_index, ts, flags | (ts - min_ts > (uint64_t)(max_ts - ts) ? AVSEEK_FLAG_BACKWARD : 0));

    // try some generic seek like av_seek_frame_generic() but with new ts semantics
}

/*******************************************************/

/**
 * Returns TRUE if the stream has accurate duration in any stream.
 *
 * @return TRUE if the stream has accurate duration for at least one component.
 */
static int av_has_duration(AVFormatContext *ic)
{
    int i;
    AVStream *st;

    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->duration != AV_NOPTS_VALUE)
            return 1;
    }
    return 0;
}

/**
 * Estimate the stream timings from the one of each components.
 *
 * Also computes the global bitrate if possible.
 */
static void av_update_stream_timings(AVFormatContext *ic)
{
    int64_t start_time, start_time1, end_time, end_time1;
    int64_t duration, duration1;
    int i;
    AVStream *st;

    start_time = INT64_MAX;
    end_time = INT64_MIN;
    duration = INT64_MIN;
    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->start_time != AV_NOPTS_VALUE && st->time_base.den) {
            start_time1= av_rescale_q(st->start_time, st->time_base, AV_TIME_BASE_Q);
            if (start_time1 < start_time)
                start_time = start_time1;
            if (st->duration != AV_NOPTS_VALUE) {
                end_time1 = start_time1
                          + av_rescale_q(st->duration, st->time_base, AV_TIME_BASE_Q);
                if (end_time1 > end_time)
                    end_time = end_time1;
            }
        }
        if (st->duration != AV_NOPTS_VALUE) {
            duration1 = av_rescale_q(st->duration, st->time_base, AV_TIME_BASE_Q);
            if (duration1 > duration)
                duration = duration1;
        }
    }
    if (start_time != INT64_MAX) {
        ic->start_time = start_time;
        if (end_time != INT64_MIN) {
            if (end_time - start_time > duration)
                duration = end_time - start_time;
        }
    }
    if (duration != INT64_MIN) {
        ic->duration = duration;
        if (ic->file_size > 0) {
            /* compute the bitrate */
            ic->bit_rate = (double)ic->file_size * 8.0 * AV_TIME_BASE /
                (double)ic->duration;
        }
    }
}

static void fill_all_stream_timings(AVFormatContext *ic)
{
    int i;
    AVStream *st;

    av_update_stream_timings(ic);
    for(i = 0;i < ic->nb_streams; i++) {
        st = ic->streams[i];
        if (st->start_time == AV_NOPTS_VALUE) {
            if(ic->start_time != AV_NOPTS_VALUE)
                st->start_time = av_rescale_q(ic->start_time, AV_TIME_BASE_Q, st->time_base);
            if(ic->duration != AV_NOPTS_VALUE)
                st->duration = av_rescale_q(ic->duration, AV_TIME_BASE_Q, st->time_base);
        }
    }
}

static void av_estimate_timings_from_bit_rate(AVFormatContext *ic)
{
    int64_t filesize, duration;
    int bit_rate, i;
    AVStream *st;

    /* if bit_rate is already set, we believe it */
    if (ic->bit_rate == 0) {
        bit_rate = 0;
        for(i=0;i<ic->nb_streams;i++) {
            st = ic->streams[i];
            bit_rate += st->codec->bit_rate;
        }
        ic->bit_rate = bit_rate;
    }

    /* if duration is already set, we believe it */
    if (ic->duration == AV_NOPTS_VALUE &&
        ic->bit_rate != 0 &&
        ic->file_size != 0)  {
        filesize = ic->file_size;
        if (filesize > 0) {
            for(i = 0; i < ic->nb_streams; i++) {
                st = ic->streams[i];
                duration= av_rescale(8*filesize, st->time_base.den, ic->bit_rate*(int64_t)st->time_base.num);
                if (st->duration == AV_NOPTS_VALUE)
                    st->duration = duration;
            }
        }
    }
}

#define DURATION_MAX_READ_SIZE 250000
#define DURATION_MAX_RETRY 3

/* only usable for MPEG-PS streams */
static void av_estimate_timings_from_pts(AVFormatContext *ic, int64_t old_offset)
{
    AVPacket pkt1, *pkt = &pkt1;
    AVStream *st;
    int read_size, i, ret;
    int64_t end_time, start_time[MAX_STREAMS];
    int64_t filesize, offset, duration;
    int retry=0;

    ic->cur_st = NULL;

    /* flush packet queue */
    flush_packet_queue(ic);

    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if(st->start_time != AV_NOPTS_VALUE){
            start_time[i]= st->start_time;
        }else if(st->first_dts != AV_NOPTS_VALUE){
            start_time[i]= st->first_dts;
        }else
            av_log(st->codec, AV_LOG_WARNING, "start time is not set in av_estimate_timings_from_pts\n");

        if (st->parser) {
            av_parser_close(st->parser);
            st->parser= NULL;
            av_free_packet(&st->cur_pkt);
        }
    }

    /* estimate the end time (duration) */
    /* XXX: may need to support wrapping */
    filesize = ic->file_size;
    end_time = AV_NOPTS_VALUE;
    do{
    offset = filesize - (DURATION_MAX_READ_SIZE<<retry);
    if (offset < 0)
        offset = 0;

    url_fseek(ic->pb, offset, SEEK_SET);
    read_size = 0;
    for(;;) {
        if (read_size >= DURATION_MAX_READ_SIZE<<(FFMAX(retry-1,0)))
            break;

        do{
            ret = av_read_packet(ic, pkt);
        }while(ret == AVERROR(EAGAIN));
        if (ret != 0)
            break;
        read_size += pkt->size;
        st = ic->streams[pkt->stream_index];
        if (pkt->pts != AV_NOPTS_VALUE &&
            start_time[pkt->stream_index] != AV_NOPTS_VALUE) {
            end_time = pkt->pts;
            duration = end_time - start_time[pkt->stream_index];
            if (duration < 0)
                duration += 1LL<<st->pts_wrap_bits;
            if (duration > 0) {
                if (st->duration == AV_NOPTS_VALUE ||
                    st->duration < duration)
                    st->duration = duration;
            }
        }
        av_free_packet(pkt);
    }
    }while(   end_time==AV_NOPTS_VALUE
           && filesize > (DURATION_MAX_READ_SIZE<<retry)
           && ++retry <= DURATION_MAX_RETRY);

    fill_all_stream_timings(ic);

    url_fseek(ic->pb, old_offset, SEEK_SET);
    for(i=0; i<ic->nb_streams; i++){
        st= ic->streams[i];
        st->cur_dts= st->first_dts;
        st->last_IP_pts = AV_NOPTS_VALUE;
    }
}

static void av_estimate_timings(AVFormatContext *ic, int64_t old_offset)
{
    int64_t file_size;

    /* get the file size, if possible */
    if (ic->iformat->flags & AVFMT_NOFILE) {
        file_size = 0;
    } else {
        file_size = url_fsize(ic->pb);
        if (file_size < 0)
            file_size = 0;
    }
    ic->file_size = file_size;

    if ((!strcmp(ic->iformat->name, "mpeg") ||
         !strcmp(ic->iformat->name, "mpegts")) &&
        file_size && !url_is_streamed(ic->pb)) {
        /* get accurate estimate from the PTSes */
        av_estimate_timings_from_pts(ic, old_offset);
    } else if (av_has_duration(ic)) {
        /* at least one component has timings - we use them for all
           the components */
        fill_all_stream_timings(ic);
    } else {
        av_log(ic, AV_LOG_WARNING, "Estimating duration from bitrate, this may be inaccurate\n");
        /* less precise: use bitrate info */
        av_estimate_timings_from_bit_rate(ic);
    }
    av_update_stream_timings(ic);

#if 0
    {
        int i;
        AVStream *st;
        for(i = 0;i < ic->nb_streams; i++) {
            st = ic->streams[i];
        printf("%d: start_time: %0.3f duration: %0.3f\n",
               i, (double)st->start_time / AV_TIME_BASE,
               (double)st->duration / AV_TIME_BASE);
        }
        printf("stream: start_time: %0.3f duration: %0.3f bitrate=%d kb/s\n",
               (double)ic->start_time / AV_TIME_BASE,
               (double)ic->duration / AV_TIME_BASE,
               ic->bit_rate / 1000);
    }
#endif
}

static int has_codec_parameters(AVCodecContext *enc)
{
    int val;
    switch(enc->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        val = enc->sample_rate && enc->channels && enc->sample_fmt != SAMPLE_FMT_NONE;
        if(!enc->frame_size &&
           (enc->codec_id == CODEC_ID_VORBIS ||
            enc->codec_id == CODEC_ID_AAC ||
            enc->codec_id == CODEC_ID_MP1 ||
            enc->codec_id == CODEC_ID_MP2 ||
            enc->codec_id == CODEC_ID_MP3 ||
            enc->codec_id == CODEC_ID_SPEEX))
            return 0;
        break;
    case AVMEDIA_TYPE_VIDEO:
        val = enc->width && enc->pix_fmt != PIX_FMT_NONE;
        break;
    default:
        val = 1;
        break;
    }
    return enc->codec_id != CODEC_ID_NONE && val != 0;
}

static int try_decode_frame(AVStream *st, AVPacket *avpkt)
{
    int16_t *samples;
    AVCodec *codec;
    int got_picture, data_size, ret=0;
    AVFrame picture;

    if(!st->codec->codec){
        codec = avcodec_find_decoder(st->codec->codec_id);
        if (!codec)
            return -1;
        ret = avcodec_open(st->codec, codec);
        if (ret < 0)
            return ret;
    }

    if(!has_codec_parameters(st->codec)){
        switch(st->codec->codec_type) {
        case AVMEDIA_TYPE_VIDEO:
            avcodec_get_frame_defaults(&picture);
            ret = avcodec_decode_video2(st->codec, &picture,
                                        &got_picture, avpkt);
            break;
        case AVMEDIA_TYPE_AUDIO:
            data_size = FFMAX(avpkt->size, AVCODEC_MAX_AUDIO_FRAME_SIZE);
            samples = av_malloc(data_size);
            if (!samples)
                goto fail;
            ret = avcodec_decode_audio3(st->codec, samples,
                                        &data_size, avpkt);
            av_free(samples);
            break;
        default:
            break;
        }
    }
 fail:
    return ret;
}

unsigned int ff_codec_get_tag(const AVCodecTag *tags, int id)
{
    while (tags->id != CODEC_ID_NONE) {
        if (tags->id == id)
            return tags->tag;
        tags++;
    }
    return 0;
}

enum CodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag)
{
    int i;
    for(i=0; tags[i].id != CODEC_ID_NONE;i++) {
        if(tag == tags[i].tag)
            return tags[i].id;
    }
    for(i=0; tags[i].id != CODEC_ID_NONE; i++) {
        if(   toupper((tag >> 0)&0xFF) == toupper((tags[i].tag >> 0)&0xFF)
           && toupper((tag >> 8)&0xFF) == toupper((tags[i].tag >> 8)&0xFF)
           && toupper((tag >>16)&0xFF) == toupper((tags[i].tag >>16)&0xFF)
           && toupper((tag >>24)&0xFF) == toupper((tags[i].tag >>24)&0xFF))
            return tags[i].id;
    }
    return CODEC_ID_NONE;
}

unsigned int av_codec_get_tag(const AVCodecTag * const *tags, enum CodecID id)
{
    int i;
    for(i=0; tags && tags[i]; i++){
        int tag= ff_codec_get_tag(tags[i], id);
        if(tag) return tag;
    }
    return 0;
}

enum CodecID av_codec_get_id(const AVCodecTag * const *tags, unsigned int tag)
{
    int i;
    for(i=0; tags && tags[i]; i++){
        enum CodecID id= ff_codec_get_id(tags[i], tag);
        if(id!=CODEC_ID_NONE) return id;
    }
    return CODEC_ID_NONE;
}

static void compute_chapters_end(AVFormatContext *s)
{
    unsigned int i;

    for (i=0; i+1<s->nb_chapters; i++)
        if (s->chapters[i]->end == AV_NOPTS_VALUE) {
            assert(s->chapters[i]->start <= s->chapters[i+1]->start);
            assert(!av_cmp_q(s->chapters[i]->time_base, s->chapters[i+1]->time_base));
            s->chapters[i]->end = s->chapters[i+1]->start;
        }

    if (s->nb_chapters && s->chapters[i]->end == AV_NOPTS_VALUE) {
        assert(s->start_time != AV_NOPTS_VALUE);
        assert(s->duration > 0);
        s->chapters[i]->end = av_rescale_q(s->start_time + s->duration,
                                           AV_TIME_BASE_Q,
                                           s->chapters[i]->time_base);
    }
}

#define MAX_STD_TIMEBASES (60*12+5)
static int get_std_framerate(int i){
    if(i<60*12) return i*1001;
    else        return ((const int[]){24,30,60,12,15})[i-60*12]*1000*12;
}

/*
 * Is the time base unreliable.
 * This is a heuristic to balance between quick acceptance of the values in
 * the headers vs. some extra checks.
 * Old DivX and Xvid often have nonsense timebases like 1fps or 2fps.
 * MPEG-2 commonly misuses field repeat flags to store different framerates.
 * And there are "variable" fps files this needs to detect as well.
 */
static int tb_unreliable(AVCodecContext *c){
    if(   c->time_base.den >= 101L*c->time_base.num
       || c->time_base.den <    5L*c->time_base.num
/*       || c->codec_tag == AV_RL32("DIVX")
       || c->codec_tag == AV_RL32("XVID")*/
       || c->codec_id == CODEC_ID_MPEG2VIDEO
       || c->codec_id == CODEC_ID_H264
       )
        return 1;
    return 0;
}

int av_find_stream_info(AVFormatContext *ic)
{
    int i, count, ret, read_size, j;
    AVStream *st;
    AVPacket pkt1, *pkt;
    int64_t last_dts[MAX_STREAMS];
    int64_t duration_gcd[MAX_STREAMS]={0};
    int duration_count[MAX_STREAMS]={0};
    double (*duration_error)[MAX_STD_TIMEBASES];
    int64_t old_offset = url_ftell(ic->pb);
    int64_t codec_info_duration[MAX_STREAMS]={0};

    duration_error = av_mallocz(MAX_STREAMS * sizeof(*duration_error));
    if (!duration_error) return AVERROR(ENOMEM);

    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if (st->codec->codec_id == CODEC_ID_AAC) {
            st->codec->sample_rate = 0;
            st->codec->frame_size = 0;
            st->codec->channels = 0;
        }
        if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
/*            if(!st->time_base.num)
                st->time_base= */
            if(!st->codec->time_base.num)
                st->codec->time_base= st->time_base;
        }
        //only for the split stuff
        if (!st->parser && !(ic->flags & AVFMT_FLAG_NOPARSE)) {
            st->parser = av_parser_init(st->codec->codec_id);
            if(st->need_parsing == AVSTREAM_PARSE_HEADERS && st->parser){
                st->parser->flags |= PARSER_FLAG_COMPLETE_FRAMES;
            }
        }
        assert(!st->codec->codec);
        //try to just open decoders, in case this is enough to get parameters
        if(!has_codec_parameters(st->codec)){
            AVCodec *codec = avcodec_find_decoder(st->codec->codec_id);
            if (codec)
                avcodec_open(st->codec, codec);
        }
    }

    for(i=0;i<MAX_STREAMS;i++){
        last_dts[i]= AV_NOPTS_VALUE;
    }

    count = 0;
    read_size = 0;
    for(;;) {
        if(url_interrupt_cb()){
            ret= AVERROR(EINTR);
            av_log(ic, AV_LOG_DEBUG, "interrupted\n");
            break;
        }

        /* check if one codec still needs to be handled */
        for(i=0;i<ic->nb_streams;i++) {
            st = ic->streams[i];
            if (!has_codec_parameters(st->codec))
                break;
            /* variable fps and no guess at the real fps */
            if(   tb_unreliable(st->codec) && !(st->r_frame_rate.num && st->avg_frame_rate.num)
               && duration_count[i]<20 && st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
                break;
            if(st->parser && st->parser->parser->split && !st->codec->extradata)
                break;
            if(st->first_dts == AV_NOPTS_VALUE)
                break;
        }
        if (i == ic->nb_streams) {
            /* NOTE: if the format has no header, then we need to read
               some packets to get most of the streams, so we cannot
               stop here */
            if (!(ic->ctx_flags & AVFMTCTX_NOHEADER)) {
                /* if we found the info for all the codecs, we can stop */
                ret = count;
                av_log(ic, AV_LOG_DEBUG, "All info found\n");
                break;
            }
        }
        /* we did not get all the codec info, but we read too much data */
        if (read_size >= ic->probesize) {
            ret = count;
            av_log(ic, AV_LOG_WARNING, "MAX_READ_SIZE:%d reached\n", ic->probesize);
            break;
        }

        /* NOTE: a new stream can be added there if no header in file
           (AVFMTCTX_NOHEADER) */
        ret = av_read_frame_internal(ic, &pkt1);
        if(ret == AVERROR(EAGAIN))
            continue;
        if (ret < 0) {
            /* EOF or error */
            ret = -1; /* we could not have all the codec parameters before EOF */
            for(i=0;i<ic->nb_streams;i++) {
                st = ic->streams[i];
                if (!has_codec_parameters(st->codec)){
                    char buf[256];
                    avcodec_string(buf, sizeof(buf), st->codec, 0);
                    av_log(ic, AV_LOG_WARNING, "Could not find codec parameters (%s)\n", buf);
                } else {
                    ret = 0;
                }
            }
            break;
        }

        pkt= add_to_pktbuf(&ic->packet_buffer, &pkt1, &ic->packet_buffer_end);
        if(av_dup_packet(pkt) < 0) {
            av_free(duration_error);
            return AVERROR(ENOMEM);
        }

        read_size += pkt->size;

        st = ic->streams[pkt->stream_index];
        if(st->codec_info_nb_frames>1) {
            if (st->time_base.den > 0 && av_rescale_q(codec_info_duration[st->index], st->time_base, AV_TIME_BASE_Q) >= ic->max_analyze_duration){
                av_log(ic, AV_LOG_WARNING, "max_analyze_duration reached\n");
                break;
            }
            codec_info_duration[st->index] += pkt->duration;
        }
            st->codec_info_nb_frames++;

        {
            int index= pkt->stream_index;
            int64_t last= last_dts[index];
            int64_t duration= pkt->dts - last;

            if(pkt->dts != AV_NOPTS_VALUE && last != AV_NOPTS_VALUE && duration>0){
                double dur= duration * av_q2d(st->time_base);

//                if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
//                    av_log(NULL, AV_LOG_ERROR, "%f\n", dur);
                if(duration_count[index] < 2)
                    memset(duration_error[index], 0, sizeof(*duration_error));
                for(i=1; i<MAX_STD_TIMEBASES; i++){
                    int framerate= get_std_framerate(i);
                    int ticks= lrintf(dur*framerate/(1001*12));
                    double error= dur - ticks*1001*12/(double)framerate;
                    duration_error[index][i] += error*error;
                }
                duration_count[index]++;
                // ignore the first 4 values, they might have some random jitter
                if (duration_count[index] > 3)
                    duration_gcd[index] = av_gcd(duration_gcd[index], duration);
            }
            if(last == AV_NOPTS_VALUE || duration_count[index]<=1)
                last_dts[pkt->stream_index]= pkt->dts;
        }
        if(st->parser && st->parser->parser->split && !st->codec->extradata){
            int i= st->parser->parser->split(st->codec, pkt->data, pkt->size);
            if(i){
                st->codec->extradata_size= i;
                st->codec->extradata= av_malloc(st->codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
                memcpy(st->codec->extradata, pkt->data, st->codec->extradata_size);
                memset(st->codec->extradata + i, 0, FF_INPUT_BUFFER_PADDING_SIZE);
            }
        }

        /* if still no information, we try to open the codec and to
           decompress the frame. We try to avoid that in most cases as
           it takes longer and uses more memory. For MPEG-4, we need to
           decompress for QuickTime. */
        if (!has_codec_parameters(st->codec))
            try_decode_frame(st, pkt);

        count++;
    }

    // close codecs which were opened in try_decode_frame()
    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if(st->codec->codec)
            avcodec_close(st->codec);
    }
    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if(st->codec_info_nb_frames>2 && !st->avg_frame_rate.num && codec_info_duration[i])
            av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
                     (st->codec_info_nb_frames-2)*(int64_t)st->time_base.den,
                      codec_info_duration[i]    *(int64_t)st->time_base.num, 60000);
        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
            if(st->codec->codec_id == CODEC_ID_RAWVIDEO && !st->codec->codec_tag && !st->codec->bits_per_coded_sample)
                st->codec->codec_tag= avcodec_pix_fmt_to_codec_tag(st->codec->pix_fmt);

            // the check for tb_unreliable() is not completely correct, since this is not about handling
            // a unreliable/inexact time base, but a time base that is finer than necessary, as e.g.
            // ipmovie.c produces.
            if (tb_unreliable(st->codec) && duration_count[i] > 15 && duration_gcd[i] > 1 && !st->r_frame_rate.num)
                av_reduce(&st->r_frame_rate.num, &st->r_frame_rate.den, st->time_base.den, st->time_base.num * duration_gcd[i], INT_MAX);
            if(duration_count[i] && !st->r_frame_rate.num
               && tb_unreliable(st->codec) /*&&
               //FIXME we should not special-case MPEG-2, but this needs testing with non-MPEG-2 ...
               st->time_base.num*duration_sum[i]/duration_count[i]*101LL > st->time_base.den*/){
                int num = 0;
                double best_error= 2*av_q2d(st->time_base);
                best_error= best_error*best_error*duration_count[i]*1000*12*30;

                for(j=1; j<MAX_STD_TIMEBASES; j++){
                    double error= duration_error[i][j] * get_std_framerate(j);
//                    if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
//                        av_log(NULL, AV_LOG_ERROR, "%f %f\n", get_std_framerate(j) / 12.0/1001, error);
                    if(error < best_error){
                        best_error= error;
                        num = get_std_framerate(j);
                    }
                }
                // do not increase frame rate by more than 1 % in order to match a standard rate.
                if (num && (!st->r_frame_rate.num || (double)num/(12*1001) < 1.01 * av_q2d(st->r_frame_rate)))
                    av_reduce(&st->r_frame_rate.num, &st->r_frame_rate.den, num, 12*1001, INT_MAX);
            }

            if (!st->r_frame_rate.num){
                if(    st->codec->time_base.den * (int64_t)st->time_base.num
                    <= st->codec->time_base.num * st->codec->ticks_per_frame * (int64_t)st->time_base.den){
                    st->r_frame_rate.num = st->codec->time_base.den;
                    st->r_frame_rate.den = st->codec->time_base.num * st->codec->ticks_per_frame;
                }else{
                    st->r_frame_rate.num = st->time_base.den;
                    st->r_frame_rate.den = st->time_base.num;
                }
            }
        }else if(st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
            if(!st->codec->bits_per_coded_sample)
                st->codec->bits_per_coded_sample= av_get_bits_per_sample(st->codec->codec_id);
        }
    }

    av_estimate_timings(ic, old_offset);

    compute_chapters_end(ic);

#if 0
    /* correct DTS for B-frame streams with no timestamps */
    for(i=0;i<ic->nb_streams;i++) {
        st = ic->streams[i];
        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
            if(b-frames){
                ppktl = &ic->packet_buffer;
                while(ppkt1){
                    if(ppkt1->stream_index != i)
                        continue;
                    if(ppkt1->pkt->dts < 0)
                        break;
                    if(ppkt1->pkt->pts != AV_NOPTS_VALUE)
                        break;
                    ppkt1->pkt->dts -= delta;
                    ppkt1= ppkt1->next;
                }
                if(ppkt1)
                    continue;
                st->cur_dts -= delta;
            }
        }
    }
#endif

    av_free(duration_error);

    return ret;
}

/*******************************************************/

int av_read_play(AVFormatContext *s)
{
    if (s->iformat->read_play)
        return s->iformat->read_play(s);
    if (s->pb)
        return av_url_read_fpause(s->pb, 0);
    return AVERROR(ENOSYS);
}

int av_read_pause(AVFormatContext *s)
{
    if (s->iformat->read_pause)
        return s->iformat->read_pause(s);
    if (s->pb)
        return av_url_read_fpause(s->pb, 1);
    return AVERROR(ENOSYS);
}

void av_close_input_stream(AVFormatContext *s)
{
    int i;
    AVStream *st;

    if (s->iformat->read_close)
        s->iformat->read_close(s);
    for(i=0;i<s->nb_streams;i++) {
        /* free all data in a stream component */
        st = s->streams[i];
        if (st->parser) {
            av_parser_close(st->parser);
            av_free_packet(&st->cur_pkt);
        }
        av_metadata_free(&st->metadata);
        av_free(st->index_entries);
        av_free(st->codec->extradata);
        av_free(st->codec);
#if LIBAVFORMAT_VERSION_INT < (53<<16)
        av_free(st->filename);
#endif
        av_free(st->priv_data);
        av_free(st);
    }
    for(i=s->nb_programs-1; i>=0; i--) {
#if LIBAVFORMAT_VERSION_INT < (53<<16)
        av_freep(&s->programs[i]->provider_name);
        av_freep(&s->programs[i]->name);
#endif
        av_metadata_free(&s->programs[i]->metadata);
        av_freep(&s->programs[i]->stream_index);
        av_freep(&s->programs[i]);
    }
    av_freep(&s->programs);
    flush_packet_queue(s);
    av_freep(&s->priv_data);
    while(s->nb_chapters--) {
#if LIBAVFORMAT_VERSION_INT < (53<<16)
        av_free(s->chapters[s->nb_chapters]->title);
#endif
        av_metadata_free(&s->chapters[s->nb_chapters]->metadata);
        av_free(s->chapters[s->nb_chapters]);
    }
    av_freep(&s->chapters);
    av_metadata_free(&s->metadata);
    av_free(s);
}

void av_close_input_file(AVFormatContext *s)
{
    ByteIOContext *pb = s->iformat->flags & AVFMT_NOFILE ? NULL : s->pb;
    av_close_input_stream(s);
    if (pb)
        url_fclose(pb);
}

AVStream *av_new_stream(AVFormatContext *s, int id)
{
    AVStream *st;
    int i;

    if (s->nb_streams >= MAX_STREAMS)
        return NULL;

    st = av_mallocz(sizeof(AVStream));
    if (!st)
        return NULL;

    st->codec= avcodec_alloc_context();
    if (s->iformat) {
        /* no default bitrate if decoding */
        st->codec->bit_rate = 0;
    }
    st->index = s->nb_streams;
    st->id = id;
    st->start_time = AV_NOPTS_VALUE;
    st->duration = AV_NOPTS_VALUE;
        /* we set the current DTS to 0 so that formats without any timestamps
           but durations get some timestamps, formats with some unknown
           timestamps have their first few packets buffered and the
           timestamps corrected before they are returned to the user */
    st->cur_dts = 0;
    st->first_dts = AV_NOPTS_VALUE;
    st->probe_packets = MAX_PROBE_PACKETS;

    /* default pts setting is MPEG-like */
    av_set_pts_info(st, 33, 1, 90000);
    st->last_IP_pts = AV_NOPTS_VALUE;
    for(i=0; i<MAX_REORDER_DELAY+1; i++)
        st->pts_buffer[i]= AV_NOPTS_VALUE;
    st->reference_dts = AV_NOPTS_VALUE;

    st->sample_aspect_ratio = (AVRational){0,1};

    s->streams[s->nb_streams++] = st;
    return st;
}

AVProgram *av_new_program(AVFormatContext *ac, int id)
{
    AVProgram *program=NULL;
    int i;

#ifdef DEBUG_SI
    av_log(ac, AV_LOG_DEBUG, "new_program: id=0x%04x\n", id);
#endif

    for(i=0; i<ac->nb_programs; i++)
        if(ac->programs[i]->id == id)
            program = ac->programs[i];

    if(!program){
        program = av_mallocz(sizeof(AVProgram));
        if (!program)
            return NULL;
        dynarray_add(&ac->programs, &ac->nb_programs, program);
        program->discard = AVDISCARD_NONE;
    }
    program->id = id;

    return program;
}

AVChapter *ff_new_chapter(AVFormatContext *s, int id, AVRational time_base, int64_t start, int64_t end, const char *title)
{
    AVChapter *chapter = NULL;
    int i;

    for(i=0; i<s->nb_chapters; i++)
        if(s->chapters[i]->id == id)
            chapter = s->chapters[i];

    if(!chapter){
        chapter= av_mallocz(sizeof(AVChapter));
        if(!chapter)
            return NULL;
        dynarray_add(&s->chapters, &s->nb_chapters, chapter);
    }
#if LIBAVFORMAT_VERSION_INT < (53<<16)
    av_free(chapter->title);
#endif
    av_metadata_set(&chapter->metadata, "title", title);
    chapter->id    = id;
    chapter->time_base= time_base;
    chapter->start = start;
    chapter->end   = end;

    return chapter;
}

/************************************************************/
/* output media file */

int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap)
{
    int ret;

    if (s->oformat->priv_data_size > 0) {
        s->priv_data = av_mallocz(s->oformat->priv_data_size);
        if (!s->priv_data)
            return AVERROR(ENOMEM);
    } else
        s->priv_data = NULL;

    if (s->oformat->set_parameters) {
        ret = s->oformat->set_parameters(s, ap);
        if (ret < 0)
            return ret;
    }
    return 0;
}

int av_write_header(AVFormatContext *s)
{
    int ret, i;
    AVStream *st;

    // some sanity checks
    if (s->nb_streams == 0) {
        av_log(s, AV_LOG_ERROR, "no streams\n");
        return -1;
    }

    for(i=0;i<s->nb_streams;i++) {
        st = s->streams[i];

        switch (st->codec->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            if(st->codec->sample_rate<=0){
                av_log(s, AV_LOG_ERROR, "sample rate not set\n");
                return -1;
            }
            if(!st->codec->block_align)
                st->codec->block_align = st->codec->channels *
                    av_get_bits_per_sample(st->codec->codec_id) >> 3;
            break;
        case AVMEDIA_TYPE_VIDEO:
            if(st->codec->time_base.num<=0 || st->codec->time_base.den<=0){ //FIXME audio too?
                av_log(s, AV_LOG_ERROR, "time base not set\n");
                return -1;
            }
            if((st->codec->width<=0 || st->codec->height<=0) && !(s->oformat->flags & AVFMT_NODIMENSIONS)){
                av_log(s, AV_LOG_ERROR, "dimensions not set\n");
                return -1;
            }
            if(av_cmp_q(st->sample_aspect_ratio, st->codec->sample_aspect_ratio)){
                av_log(s, AV_LOG_ERROR, "Aspect ratio mismatch between encoder and muxer layer\n");
                return -1;
            }
            break;
        }

        if(s->oformat->codec_tag){
            if(st->codec->codec_tag){
                //FIXME
                //check that tag + id is in the table
                //if neither is in the table -> OK
                //if tag is in the table with another id -> FAIL
                //if id is in the table with another tag -> FAIL unless strict < ?
            }else
                st->codec->codec_tag= av_codec_get_tag(s->oformat->codec_tag, st->codec->codec_id);
        }

        if(s->oformat->flags & AVFMT_GLOBALHEADER &&
            !(st->codec->flags & CODEC_FLAG_GLOBAL_HEADER))
          av_log(s, AV_LOG_WARNING, "Codec for stream %d does not use global headers but container format requires global headers\n", i);
    }

    if (!s->priv_data && s->oformat->priv_data_size > 0) {
        s->priv_data = av_mallocz(s->oformat->priv_data_size);
        if (!s->priv_data)
            return AVERROR(ENOMEM);
    }

#if LIBAVFORMAT_VERSION_MAJOR < 53
    ff_metadata_mux_compat(s);
#endif

    /* set muxer identification string */
    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
        AVMetadata *m;
        AVMetadataTag *t;

        if (!(m = av_mallocz(sizeof(AVMetadata))))
            return AVERROR(ENOMEM);
        av_metadata_set2(&m, "encoder", LIBAVFORMAT_IDENT, 0);
        metadata_conv(&m, s->oformat->metadata_conv, NULL);
        if ((t = av_metadata_get(m, "", NULL, AV_METADATA_IGNORE_SUFFIX)))
            av_metadata_set2(&s->metadata, t->key, t->value, 0);
        av_metadata_free(&m);
    }

    if(s->oformat->write_header){
        ret = s->oformat->write_header(s);
        if (ret < 0)
            return ret;
    }

    /* init PTS generation */
    for(i=0;i<s->nb_streams;i++) {
        int64_t den = AV_NOPTS_VALUE;
        st = s->streams[i];

        switch (st->codec->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            den = (int64_t)st->time_base.num * st->codec->sample_rate;
            break;
        case AVMEDIA_TYPE_VIDEO:
            den = (int64_t)st->time_base.num * st->codec->time_base.den;
            break;
        default:
            break;
        }
        if (den != AV_NOPTS_VALUE) {
            if (den <= 0)
                return AVERROR_INVALIDDATA;
            av_frac_init(&st->pts, 0, 0, den);
        }
    }
    return 0;
}

//FIXME merge with compute_pkt_fields
static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt){
    int delay = FFMAX(st->codec->has_b_frames, !!st->codec->max_b_frames);
    int num, den, frame_size, i;

//    av_log(s, AV_LOG_DEBUG, "av_write_frame: pts:%"PRId64" dts:%"PRId64" cur_dts:%"PRId64" b:%d size:%d st:%d\n", pkt->pts, pkt->dts, st->cur_dts, delay, pkt->size, pkt->stream_index);

/*    if(pkt->pts == AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE)
        return -1;*/

    /* duration field */
    if (pkt->duration == 0) {
        compute_frame_duration(&num, &den, st, NULL, pkt);
        if (den && num) {
            pkt->duration = av_rescale(1, num * (int64_t)st->time_base.den * st->codec->ticks_per_frame, den * (int64_t)st->time_base.num);
        }
    }

    if(pkt->pts == AV_NOPTS_VALUE && pkt->dts != AV_NOPTS_VALUE && delay==0)
        pkt->pts= pkt->dts;

    //XXX/FIXME this is a temporary hack until all encoders output pts
    if((pkt->pts == 0 || pkt->pts == AV_NOPTS_VALUE) && pkt->dts == AV_NOPTS_VALUE && !delay){
        pkt->dts=
//        pkt->pts= st->cur_dts;
        pkt->pts= st->pts.val;
    }

    //calculate dts from pts
    if(pkt->pts != AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE && delay <= MAX_REORDER_DELAY){
        st->pts_buffer[0]= pkt->pts;
        for(i=1; i<delay+1 && st->pts_buffer[i] == AV_NOPTS_VALUE; i++)
            st->pts_buffer[i]= pkt->pts + (i-delay-1) * pkt->duration;
        for(i=0; i<delay && st->pts_buffer[i] > st->pts_buffer[i+1]; i++)
            FFSWAP(int64_t, st->pts_buffer[i], st->pts_buffer[i+1]);

        pkt->dts= st->pts_buffer[0];
    }

    if(st->cur_dts && st->cur_dts != AV_NOPTS_VALUE && st->cur_dts >= pkt->dts){
        av_log(s, AV_LOG_ERROR,
               "st:%d error, non monotone timestamps %"PRId64" >= %"PRId64"\n",
               st->index, st->cur_dts, pkt->dts);
        return -1;
    }
    if(pkt->dts != AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE && pkt->pts < pkt->dts){
        av_log(s, AV_LOG_ERROR, "st:%d error, pts < dts\n", st->index);
        return -1;
    }

//    av_log(s, AV_LOG_DEBUG, "av_write_frame: pts2:%"PRId64" dts2:%"PRId64"\n", pkt->pts, pkt->dts);
    st->cur_dts= pkt->dts;
    st->pts.val= pkt->dts;

    /* update pts */
    switch (st->codec->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        frame_size = get_audio_frame_size(st->codec, pkt->size);

        /* HACK/FIXME, we skip the initial 0 size packets as they are most
           likely equal to the encoder delay, but it would be better if we
           had the real timestamps from the encoder */
        if (frame_size >= 0 && (pkt->size || st->pts.num!=st->pts.den>>1 || st->pts.val)) {
            av_frac_add(&st->pts, (int64_t)st->time_base.den * frame_size);
        }
        break;
    case AVMEDIA_TYPE_VIDEO:
        av_frac_add(&st->pts, (int64_t)st->time_base.den * st->codec->time_base.num);
        break;
    default:
        break;
    }
    return 0;
}

int av_write_frame(AVFormatContext *s, AVPacket *pkt)
{
    int ret = compute_pkt_fields2(s, s->streams[pkt->stream_index], pkt);

    if(ret<0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
        return ret;

    ret= s->oformat->write_packet(s, pkt);
    if(!ret)
        ret= url_ferror(s->pb);
    return ret;
}

void ff_interleave_add_packet(AVFormatContext *s, AVPacket *pkt,
                              int (*compare)(AVFormatContext *, AVPacket *, AVPacket *))
{
    AVPacketList **next_point, *this_pktl;

    this_pktl = av_mallocz(sizeof(AVPacketList));
    this_pktl->pkt= *pkt;
    pkt->destruct= NULL;             // do not free original but only the copy
    av_dup_packet(&this_pktl->pkt);  // duplicate the packet if it uses non-alloced memory

    if(s->streams[pkt->stream_index]->last_in_packet_buffer){
        next_point = &(s->streams[pkt->stream_index]->last_in_packet_buffer->next);
    }else
        next_point = &s->packet_buffer;

    if(*next_point){
        if(compare(s, &s->packet_buffer_end->pkt, pkt)){
            while(!compare(s, &(*next_point)->pkt, pkt)){
                next_point= &(*next_point)->next;
            }
            goto next_non_null;
        }else{
            next_point = &(s->packet_buffer_end->next);
        }
    }
    assert(!*next_point);

    s->packet_buffer_end= this_pktl;
next_non_null:

    this_pktl->next= *next_point;

    s->streams[pkt->stream_index]->last_in_packet_buffer=
    *next_point= this_pktl;
}

int ff_interleave_compare_dts(AVFormatContext *s, AVPacket *next, AVPacket *pkt)
{
    AVStream *st = s->streams[ pkt ->stream_index];
    AVStream *st2= s->streams[ next->stream_index];
    int64_t a= st2->time_base.num * (int64_t)st ->time_base.den;
    int64_t b= st ->time_base.num * (int64_t)st2->time_base.den;
    return av_rescale_rnd(pkt->dts, b, a, AV_ROUND_DOWN) < next->dts;
}

int av_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush){
    AVPacketList *pktl;
    int stream_count=0;
    int i;

    if(pkt){
        ff_interleave_add_packet(s, pkt, ff_interleave_compare_dts);
    }

    for(i=0; i < s->nb_streams; i++)
        stream_count+= !!s->streams[i]->last_in_packet_buffer;

    if(stream_count && (s->nb_streams == stream_count || flush)){
        pktl= s->packet_buffer;
        *out= pktl->pkt;

        s->packet_buffer= pktl->next;
        if(!s->packet_buffer)
            s->packet_buffer_end= NULL;

        if(s->streams[out->stream_index]->last_in_packet_buffer == pktl)
            s->streams[out->stream_index]->last_in_packet_buffer= NULL;
        av_freep(&pktl);
        return 1;
    }else{
        av_init_packet(out);
        return 0;
    }
}

/**
 * Interleaves an AVPacket correctly so it can be muxed.
 * @param out the interleaved packet will be output here
 * @param in the input packet
 * @param flush 1 if no further packets are available as input and all
 *              remaining packets should be output
 * @return 1 if a packet was output, 0 if no packet could be output,
 *         < 0 if an error occurred
 */
static int av_interleave_packet(AVFormatContext *s, AVPacket *out, AVPacket *in, int flush){
    if(s->oformat->interleave_packet)
        return s->oformat->interleave_packet(s, out, in, flush);
    else
        return av_interleave_packet_per_dts(s, out, in, flush);
}

int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt){
    AVStream *st= s->streams[ pkt->stream_index];

    //FIXME/XXX/HACK drop zero sized packets
    if(st->codec->codec_type == AVMEDIA_TYPE_AUDIO && pkt->size==0)
        return 0;

//av_log(NULL, AV_LOG_DEBUG, "av_interleaved_write_frame %d %"PRId64" %"PRId64"\n", pkt->size, pkt->dts, pkt->pts);
    if(compute_pkt_fields2(s, st, pkt) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
        return -1;

    if(pkt->dts == AV_NOPTS_VALUE && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
        return -1;

    for(;;){
        AVPacket opkt;
        int ret= av_interleave_packet(s, &opkt, pkt, 0);
        if(ret<=0) //FIXME cleanup needed for ret<0 ?
            return ret;

        ret= s->oformat->write_packet(s, &opkt);

        av_free_packet(&opkt);
        pkt= NULL;

        if(ret<0)
            return ret;
        if(url_ferror(s->pb))
            return url_ferror(s->pb);
    }
}

int av_write_trailer(AVFormatContext *s)
{
    int ret, i;

    for(;;){
        AVPacket pkt;
        ret= av_interleave_packet(s, &pkt, NULL, 1);
        if(ret<0) //FIXME cleanup needed for ret<0 ?
            goto fail;
        if(!ret)
            break;

        ret= s->oformat->write_packet(s, &pkt);

        av_free_packet(&pkt);

        if(ret<0)
            goto fail;
        if(url_ferror(s->pb))
            goto fail;
    }

    if(s->oformat->write_trailer)
        ret = s->oformat->write_trailer(s);
fail:
    if(ret == 0)
       ret=url_ferror(s->pb);
    for(i=0;i<s->nb_streams;i++) {
        av_freep(&s->streams[i]->priv_data);
        av_freep(&s->streams[i]->index_entries);
    }
    av_freep(&s->priv_data);
    return ret;
}

void ff_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx)
{
    int i, j;
    AVProgram *program=NULL;
    void *tmp;

    if (idx >= ac->nb_streams) {
        av_log(ac, AV_LOG_ERROR, "stream index %d is not valid\n", idx);
        return;
    }

    for(i=0; i<ac->nb_programs; i++){
        if(ac->programs[i]->id != progid)
            continue;
        program = ac->programs[i];
        for(j=0; j<program->nb_stream_indexes; j++)
            if(program->stream_index[j] == idx)
                return;

        tmp = av_realloc(program->stream_index, sizeof(unsigned int)*(program->nb_stream_indexes+1));
        if(!tmp)
            return;
        program->stream_index = tmp;
        program->stream_index[program->nb_stream_indexes++] = idx;
        return;
    }
}

static void print_fps(double d, const char *postfix){
    uint64_t v= lrintf(d*100);
    if     (v% 100      ) av_log(NULL, AV_LOG_INFO, ", %3.2f %s", d, postfix);
    else if(v%(100*1000)) av_log(NULL, AV_LOG_INFO, ", %1.0f %s", d, postfix);
    else                  av_log(NULL, AV_LOG_INFO, ", %1.0fk %s", d/1000, postfix);
}

static void dump_metadata(void *ctx, AVMetadata *m, const char *indent)
{
    if(m && !(m->count == 1 && av_metadata_get(m, "language", NULL, 0))){
        AVMetadataTag *tag=NULL;

        av_log(ctx, AV_LOG_INFO, "%sMetadata:\n", indent);
        while((tag=av_metadata_get(m, "", tag, AV_METADATA_IGNORE_SUFFIX))) {
            if(strcmp("language", tag->key))
                av_log(ctx, AV_LOG_INFO, "%s  %-16s: %s\n", indent, tag->key, tag->value);
        }
    }
}

/* "user interface" functions */
static void dump_stream_format(AVFormatContext *ic, int i, int index, int is_output)
{
    char buf[256];
    int flags = (is_output ? ic->oformat->flags : ic->iformat->flags);
    AVStream *st = ic->streams[i];
    int g = av_gcd(st->time_base.num, st->time_base.den);
    AVMetadataTag *lang = av_metadata_get(st->metadata, "language", NULL, 0);
    avcodec_string(buf, sizeof(buf), st->codec, is_output);
    av_log(NULL, AV_LOG_INFO, "    Stream #%d.%d", index, i);
    /* the pid is an important information, so we display it */
    /* XXX: add a generic system */
    if (flags & AVFMT_SHOW_IDS)
        av_log(NULL, AV_LOG_INFO, "[0x%x]", st->id);
    if (lang)
        av_log(NULL, AV_LOG_INFO, "(%s)", lang->value);
    av_log(NULL, AV_LOG_DEBUG, ", %d, %d/%d", st->codec_info_nb_frames, st->time_base.num/g, st->time_base.den/g);
    av_log(NULL, AV_LOG_INFO, ": %s", buf);
    if (st->sample_aspect_ratio.num && // default
        av_cmp_q(st->sample_aspect_ratio, st->codec->sample_aspect_ratio)) {
        AVRational display_aspect_ratio;
        av_reduce(&display_aspect_ratio.num, &display_aspect_ratio.den,
                  st->codec->width*st->sample_aspect_ratio.num,
                  st->codec->height*st->sample_aspect_ratio.den,
                  1024*1024);
        av_log(NULL, AV_LOG_INFO, ", PAR %d:%d DAR %d:%d",
                 st->sample_aspect_ratio.num, st->sample_aspect_ratio.den,
                 display_aspect_ratio.num, display_aspect_ratio.den);
    }
    if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
        if(st->avg_frame_rate.den && st->avg_frame_rate.num)
            print_fps(av_q2d(st->avg_frame_rate), "fps");
        if(st->r_frame_rate.den && st->r_frame_rate.num)
            print_fps(av_q2d(st->r_frame_rate), "tbr");
        if(st->time_base.den && st->time_base.num)
            print_fps(1/av_q2d(st->time_base), "tbn");
        if(st->codec->time_base.den && st->codec->time_base.num)
            print_fps(1/av_q2d(st->codec->time_base), "tbc");
    }
    av_log(NULL, AV_LOG_INFO, "\n");
    dump_metadata(NULL, st->metadata, "    ");
}

void dump_format(AVFormatContext *ic,
                 int index,
                 const char *url,
                 int is_output)
{
    int i;
    uint8_t *printed = av_mallocz(ic->nb_streams);
    if (ic->nb_streams && !printed)
        return;

    av_log(NULL, AV_LOG_INFO, "%s #%d, %s, %s '%s':\n",
            is_output ? "Output" : "Input",
            index,
            is_output ? ic->oformat->name : ic->iformat->name,
            is_output ? "to" : "from", url);
    dump_metadata(NULL, ic->metadata, "  ");
    if (!is_output) {
        av_log(NULL, AV_LOG_INFO, "  Duration: ");
        if (ic->duration != AV_NOPTS_VALUE) {
            int hours, mins, secs, us;
            secs = ic->duration / AV_TIME_BASE;
            us = ic->duration % AV_TIME_BASE;
            mins = secs / 60;
            secs %= 60;
            hours = mins / 60;
            mins %= 60;
            av_log(NULL, AV_LOG_INFO, "%02d:%02d:%02d.%02d", hours, mins, secs,
                   (100 * us) / AV_TIME_BASE);
        } else {
            av_log(NULL, AV_LOG_INFO, "N/A");
        }
        if (ic->start_time != AV_NOPTS_VALUE) {
            int secs, us;
            av_log(NULL, AV_LOG_INFO, ", start: ");
            secs = ic->start_time / AV_TIME_BASE;
            us = ic->start_time % AV_TIME_BASE;
            av_log(NULL, AV_LOG_INFO, "%d.%06d",
                   secs, (int)av_rescale(us, 1000000, AV_TIME_BASE));
        }
        av_log(NULL, AV_LOG_INFO, ", bitrate: ");
        if (ic->bit_rate) {
            av_log(NULL, AV_LOG_INFO,"%d kb/s", ic->bit_rate / 1000);
        } else {
            av_log(NULL, AV_LOG_INFO, "N/A");
        }
        av_log(NULL, AV_LOG_INFO, "\n");
    }
    for (i = 0; i < ic->nb_chapters; i++) {
        AVChapter *ch = ic->chapters[i];
        av_log(NULL, AV_LOG_INFO, "    Chapter #%d.%d: ", index, i);
        av_log(NULL, AV_LOG_INFO, "start %f, ", ch->start * av_q2d(ch->time_base));
        av_log(NULL, AV_LOG_INFO, "end %f\n",   ch->end   * av_q2d(ch->time_base));

        dump_metadata(NULL, ch->metadata, "    ");
    }
    if(ic->nb_programs) {
        int j, k, total = 0;
        for(j=0; j<ic->nb_programs; j++) {
            AVMetadataTag *name = av_metadata_get(ic->programs[j]->metadata,
                                                  "name", NULL, 0);
            av_log(NULL, AV_LOG_INFO, "  Program %d %s\n", ic->programs[j]->id,
                   name ? name->value : "");
            dump_metadata(NULL, ic->programs[j]->metadata, "    ");
            for(k=0; k<ic->programs[j]->nb_stream_indexes; k++) {
                dump_stream_format(ic, ic->programs[j]->stream_index[k], index, is_output);
                printed[ic->programs[j]->stream_index[k]] = 1;
            }
            total += ic->programs[j]->nb_stream_indexes;
        }
        if (total < ic->nb_streams)
            av_log(NULL, AV_LOG_INFO, "  No Program\n");
    }
    for(i=0;i<ic->nb_streams;i++)
        if (!printed[i])
            dump_stream_format(ic, i, index, is_output);

    av_free(printed);
}

#if LIBAVFORMAT_VERSION_MAJOR < 53
int parse_image_size(int *width_ptr, int *height_ptr, const char *str)
{
    return av_parse_video_frame_size(width_ptr, height_ptr, str);
}

int parse_frame_rate(int *frame_rate_num, int *frame_rate_den, const char *arg)
{
    AVRational frame_rate;
    int ret = av_parse_video_frame_rate(&frame_rate, arg);
    *frame_rate_num= frame_rate.num;
    *frame_rate_den= frame_rate.den;
    return ret;
}
#endif

int64_t av_gettime(void)
{
    struct timeval tv;
    gettimeofday(&tv,NULL);
    return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
}

uint64_t ff_ntp_time(void)
{
  return (av_gettime() / 1000) * 1000 + NTP_OFFSET_US;
}

int64_t parse_date(const char *datestr, int duration)
{
    const char *p;
    int64_t t;
    struct tm dt;
    int i;
    static const char * const date_fmt[] = {
        "%Y-%m-%d",
        "%Y%m%d",
    };
    static const char * const time_fmt[] = {
        "%H:%M:%S",
        "%H%M%S",
    };
    const char *q;
    int is_utc, len;
    char lastch;
    int negative = 0;

#undef time
    time_t now = time(0);

    len = strlen(datestr);
    if (len > 0)
        lastch = datestr[len - 1];
    else
        lastch = '\0';
    is_utc = (lastch == 'z' || lastch == 'Z');

    memset(&dt, 0, sizeof(dt));

    p = datestr;
    q = NULL;
    if (!duration) {
        if (!strncasecmp(datestr, "now", len))
            return (int64_t) now * 1000000;

        /* parse the year-month-day part */
        for (i = 0; i < FF_ARRAY_ELEMS(date_fmt); i++) {
            q = small_strptime(p, date_fmt[i], &dt);
            if (q) {
                break;
            }
        }

        /* if the year-month-day part is missing, then take the
         * current year-month-day time */
        if (!q) {
            if (is_utc) {
                dt = *gmtime(&now);
            } else {
                dt = *localtime(&now);
            }
            dt.tm_hour = dt.tm_min = dt.tm_sec = 0;
        } else {
            p = q;
        }

        if (*p == 'T' || *p == 't' || *p == ' ')
            p++;

        /* parse the hour-minute-second part */
        for (i = 0; i < FF_ARRAY_ELEMS(time_fmt); i++) {
            q = small_strptime(p, time_fmt[i], &dt);
            if (q) {
                break;
            }
        }
    } else {
        /* parse datestr as a duration */
        if (p[0] == '-') {
            negative = 1;
            ++p;
        }
        /* parse datestr as HH:MM:SS */
        q = small_strptime(p, time_fmt[0], &dt);
        if (!q) {
            /* parse datestr as S+ */
            dt.tm_sec = strtol(p, (char **)&q, 10);
            if (q == p)
                /* the parsing didn't succeed */
                return INT64_MIN;
            dt.tm_min = 0;
            dt.tm_hour = 0;
        }
    }

    /* Now we have all the fields that we can get */
    if (!q) {
        return INT64_MIN;
    }

    if (duration) {
        t = dt.tm_hour * 3600 + dt.tm_min * 60 + dt.tm_sec;
    } else {
        dt.tm_isdst = -1;       /* unknown */
        if (is_utc) {
            t = mktimegm(&dt);
        } else {
            t = mktime(&dt);
        }
    }

    t *= 1000000;

    /* parse the .m... part */
    if (*q == '.') {
        int val, n;
        q++;
        for (val = 0, n = 100000; n >= 1; n /= 10, q++) {
            if (!isdigit(*q))
                break;
            val += n * (*q - '0');
        }
        t += val;
    }
    return negative ? -t : t;
}

int find_info_tag(char *arg, int arg_size, const char *tag1, const char *info)
{
    const char *p;
    char tag[128], *q;

    p = info;
    if (*p == '?')
        p++;
    for(;;) {
        q = tag;
        while (*p != '\0' && *p != '=' && *p != '&') {
            if ((q - tag) < sizeof(tag) - 1)
                *q++ = *p;
            p++;
        }
        *q = '\0';
        q = arg;
        if (*p == '=') {
            p++;
            while (*p != '&' && *p != '\0') {
                if ((q - arg) < arg_size - 1) {
                    if (*p == '+')
                        *q++ = ' ';
                    else
                        *q++ = *p;
                }
                p++;
            }
            *q = '\0';
        }
        if (!strcmp(tag, tag1))
            return 1;
        if (*p != '&')
            break;
        p++;
    }
    return 0;
}

int av_get_frame_filename(char *buf, int buf_size,
                          const char *path, int number)
{
    const char *p;
    char *q, buf1[20], c;
    int nd, len, percentd_found;

    q = buf;
    p = path;
    percentd_found = 0;
    for(;;) {
        c = *p++;
        if (c == '\0')
            break;
        if (c == '%') {
            do {
                nd = 0;
                while (isdigit(*p)) {
                    nd = nd * 10 + *p++ - '0';
                }
                c = *p++;
            } while (isdigit(c));

            switch(c) {
            case '%':
                goto addchar;
            case 'd':
                if (percentd_found)
                    goto fail;
                percentd_found = 1;
                snprintf(buf1, sizeof(buf1), "%0*d", nd, number);
                len = strlen(buf1);
                if ((q - buf + len) > buf_size - 1)
                    goto fail;
                memcpy(q, buf1, len);
                q += len;
                break;
            default:
                goto fail;
            }
        } else {
        addchar:
            if ((q - buf) < buf_size - 1)
                *q++ = c;
        }
    }
    if (!percentd_found)
        goto fail;
    *q = '\0';
    return 0;
 fail:
    *q = '\0';
    return -1;
}

static void hex_dump_internal(void *avcl, FILE *f, int level, uint8_t *buf, int size)
{
    int len, i, j, c;
#undef fprintf
#define PRINT(...) do { if (!f) av_log(avcl, level, __VA_ARGS__); else fprintf(f, __VA_ARGS__); } while(0)

    for(i=0;i<size;i+=16) {
        len = size - i;
        if (len > 16)
            len = 16;
        PRINT("%08x ", i);
        for(j=0;j<16;j++) {
            if (j < len)
                PRINT(" %02x", buf[i+j]);
            else
                PRINT("   ");
        }
        PRINT(" ");
        for(j=0;j<len;j++) {
            c = buf[i+j];
            if (c < ' ' || c > '~')
                c = '.';
            PRINT("%c", c);
        }
        PRINT("\n");
    }
#undef PRINT
}

void av_hex_dump(FILE *f, uint8_t *buf, int size)
{
    hex_dump_internal(NULL, f, 0, buf, size);
}

void av_hex_dump_log(void *avcl, int level, uint8_t *buf, int size)
{
    hex_dump_internal(avcl, NULL, level, buf, size);
}

 //FIXME needs to know the time_base
static void pkt_dump_internal(void *avcl, FILE *f, int level, AVPacket *pkt, int dump_payload)
{
#undef fprintf
#define PRINT(...) do { if (!f) av_log(avcl, level, __VA_ARGS__); else fprintf(f, __VA_ARGS__); } while(0)
    PRINT("stream #%d:\n", pkt->stream_index);
    PRINT("  keyframe=%d\n", ((pkt->flags & AV_PKT_FLAG_KEY) != 0));
    PRINT("  duration=%0.3f\n", (double)pkt->duration / AV_TIME_BASE);
    /* DTS is _always_ valid after av_read_frame() */
    PRINT("  dts=");
    if (pkt->dts == AV_NOPTS_VALUE)
        PRINT("N/A");
    else
        PRINT("%0.3f", (double)pkt->dts / AV_TIME_BASE);
    /* PTS may not be known if B-frames are present. */
    PRINT("  pts=");
    if (pkt->pts == AV_NOPTS_VALUE)
        PRINT("N/A");
    else
        PRINT("%0.3f", (double)pkt->pts / AV_TIME_BASE);
    PRINT("\n");
    PRINT("  size=%d\n", pkt->size);
#undef PRINT
    if (dump_payload)
        av_hex_dump(f, pkt->data, pkt->size);
}

void av_pkt_dump(FILE *f, AVPacket *pkt, int dump_payload)
{
    pkt_dump_internal(NULL, f, 0, pkt, dump_payload);
}

void av_pkt_dump_log(void *avcl, int level, AVPacket *pkt, int dump_payload)
{
    pkt_dump_internal(avcl, NULL, level, pkt, dump_payload);
}

void ff_url_split(char *proto, int proto_size,
                  char *authorization, int authorization_size,
                  char *hostname, int hostname_size,
                  int *port_ptr,
                  char *path, int path_size,
                  const char *url)
{
    const char *p, *ls, *at, *col, *brk;

    if (port_ptr)               *port_ptr = -1;
    if (proto_size > 0)         proto[0] = 0;
    if (authorization_size > 0) authorization[0] = 0;
    if (hostname_size > 0)      hostname[0] = 0;
    if (path_size > 0)          path[0] = 0;

    /* parse protocol */
    if ((p = strchr(url, ':'))) {
        av_strlcpy(proto, url, FFMIN(proto_size, p + 1 - url));
        p++; /* skip ':' */
        if (*p == '/') p++;
        if (*p == '/') p++;
    } else {
        /* no protocol means plain filename */
        av_strlcpy(path, url, path_size);
        return;
    }

    /* separate path from hostname */
    ls = strchr(p, '/');
    if(!ls)
        ls = strchr(p, '?');
    if(ls)
        av_strlcpy(path, ls, path_size);
    else
        ls = &p[strlen(p)]; // XXX

    /* the rest is hostname, use that to parse auth/port */
    if (ls != p) {
        /* authorization (user[:pass]@hostname) */
        if ((at = strchr(p, '@')) && at < ls) {
            av_strlcpy(authorization, p,
                       FFMIN(authorization_size, at + 1 - p));
            p = at + 1; /* skip '@' */
        }

        if (*p == '[' && (brk = strchr(p, ']')) && brk < ls) {
            /* [host]:port */
            av_strlcpy(hostname, p + 1,
                       FFMIN(hostname_size, brk - p));
            if (brk[1] == ':' && port_ptr)
                *port_ptr = atoi(brk + 2);
        } else if ((col = strchr(p, ':')) && col < ls) {
            av_strlcpy(hostname, p,
                       FFMIN(col + 1 - p, hostname_size));
            if (port_ptr) *port_ptr = atoi(col + 1);
        } else
            av_strlcpy(hostname, p,
                       FFMIN(ls + 1 - p, hostname_size));
    }
}

char *ff_data_to_hex(char *buff, const uint8_t *src, int s, int lowercase)
{
    int i;
    static const char hex_table_uc[16] = { '0', '1', '2', '3',
                                           '4', '5', '6', '7',
                                           '8', '9', 'A', 'B',
                                           'C', 'D', 'E', 'F' };
    static const char hex_table_lc[16] = { '0', '1', '2', '3',
                                           '4', '5', '6', '7',
                                           '8', '9', 'a', 'b',
                                           'c', 'd', 'e', 'f' };
    const char *hex_table = lowercase ? hex_table_lc : hex_table_uc;

    for(i = 0; i < s; i++) {
        buff[i * 2]     = hex_table[src[i] >> 4];
        buff[i * 2 + 1] = hex_table[src[i] & 0xF];
    }

    return buff;
}

void av_set_pts_info(AVStream *s, int pts_wrap_bits,
                     unsigned int pts_num, unsigned int pts_den)
{
    s->pts_wrap_bits = pts_wrap_bits;

    if(av_reduce(&s->time_base.num, &s->time_base.den, pts_num, pts_den, INT_MAX)){
        if(s->time_base.num != pts_num)
            av_log(NULL, AV_LOG_DEBUG, "st:%d removing common factor %d from timebase\n", s->index, pts_num/s->time_base.num);
    }else
        av_log(NULL, AV_LOG_WARNING, "st:%d has too large timebase, reducing\n", s->index);

    if(!s->time_base.num || !s->time_base.den)
        s->time_base.num= s->time_base.den= 0;
}

int ff_url_join(char *str, int size, const char *proto,
                const char *authorization, const char *hostname,
                int port, const char *fmt, ...)
{
#if CONFIG_NETWORK
    struct addrinfo hints, *ai;
#endif

    str[0] = '\0';
    if (proto)
        av_strlcatf(str, size, "%s://", proto);
    if (authorization)
        av_strlcatf(str, size, "%s@", authorization);
#if CONFIG_NETWORK && defined(AF_INET6)
    /* Determine if hostname is a numerical IPv6 address,
     * properly escape it within [] in that case. */
    memset(&hints, 0, sizeof(hints));
    hints.ai_flags = AI_NUMERICHOST;
    if (!getaddrinfo(hostname, NULL, &hints, &ai)) {
        if (ai->ai_family == AF_INET6) {
            av_strlcat(str, "[", size);
            av_strlcat(str, hostname, size);
            av_strlcat(str, "]", size);
        } else {
            av_strlcat(str, hostname, size);
        }
        freeaddrinfo(ai);
    } else
#endif
        /* Not an IPv6 address, just output the plain string. */
        av_strlcat(str, hostname, size);

    if (port >= 0)
        av_strlcatf(str, size, ":%d", port);
    if (fmt) {
        va_list vl;
        int len = strlen(str);

        va_start(vl, fmt);
        vsnprintf(str + len, size > len ? size - len : 0, fmt, vl);
        va_end(vl);
    }
    return strlen(str);
}