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FFmpeg/libavformat/segment.c

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/*
* Copyright (c) 2011, Luca Barbato
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file generic segmenter
* M3U8 specification can be find here:
* @url{http://tools.ietf.org/id/draft-pantos-http-live-streaming-08.txt}
*/
#include <float.h>
#include "avformat.h"
#include "internal.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
#include "libavutil/avstring.h"
#include "libavutil/parseutils.h"
#include "libavutil/mathematics.h"
#include "libavutil/timestamp.h"
typedef enum {
LIST_TYPE_UNDEFINED = -1,
LIST_TYPE_FLAT = 0,
LIST_TYPE_CSV,
LIST_TYPE_M3U8,
LIST_TYPE_EXT, ///< deprecated
LIST_TYPE_NB,
} ListType;
#define SEGMENT_LIST_FLAG_CACHE 1
#define SEGMENT_LIST_FLAG_LIVE 2
typedef struct {
const AVClass *class; /**< Class for private options. */
int segment_idx; ///< index of the segment file to write, starting from 0
int segment_idx_wrap; ///< number after which the index wraps
int segment_count; ///< number of segment files already written
AVOutputFormat *oformat;
AVFormatContext *avf;
char *format; ///< format to use for output segment files
char *list; ///< filename for the segment list file
int list_flags; ///< flags affecting list generation
int list_size; ///< number of entries for the segment list file
double list_max_segment_time; ///< max segment time in the current list
ListType list_type; ///< set the list type
AVIOContext *list_pb; ///< list file put-byte context
char *time_str; ///< segment duration specification string
int64_t time; ///< segment duration
char *times_str; ///< segment times specification string
int64_t *times; ///< list of segment interval specification
int nb_times; ///< number of elments in the times array
char *time_delta_str; ///< approximation value duration used for the segment times
int64_t time_delta;
int individual_header_trailer; /**< Set by a private option. */
int write_header_trailer; /**< Set by a private option. */
int reset_timestamps; ///< reset timestamps at the begin of each segment
int has_video;
double start_time, end_time;
int64_t start_pts, start_dts;
int is_first_pkt; ///< tells if it is the first packet in the segment
} SegmentContext;
static void print_csv_escaped_str(AVIOContext *ctx, const char *str)
{
int needs_quoting = !!str[strcspn(str, "\",\n\r")];
if (needs_quoting)
avio_w8(ctx, '"');
for (; *str; str++) {
if (*str == '"')
avio_w8(ctx, '"');
avio_w8(ctx, *str);
}
if (needs_quoting)
avio_w8(ctx, '"');
}
static int segment_mux_init(AVFormatContext *s)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc;
int i;
seg->avf = oc = avformat_alloc_context();
if (!oc)
return AVERROR(ENOMEM);
oc->oformat = seg->oformat;
oc->interrupt_callback = s->interrupt_callback;
for (i = 0; i < s->nb_streams; i++) {
AVStream *st;
AVCodecContext *icodec, *ocodec;
if (!(st = avformat_new_stream(oc, NULL)))
return AVERROR(ENOMEM);
icodec = s->streams[i]->codec;
ocodec = st->codec;
avcodec_copy_context(ocodec, icodec);
if (!oc->oformat->codec_tag ||
av_codec_get_id (oc->oformat->codec_tag, icodec->codec_tag) == ocodec->codec_id ||
av_codec_get_tag(oc->oformat->codec_tag, icodec->codec_id) <= 0) {
ocodec->codec_tag = icodec->codec_tag;
} else {
ocodec->codec_tag = 0;
}
st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
}
return 0;
}
static int set_segment_filename(AVFormatContext *s)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc = seg->avf;
if (seg->segment_idx_wrap)
seg->segment_idx %= seg->segment_idx_wrap;
if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
s->filename, seg->segment_idx) < 0) {
av_log(oc, AV_LOG_ERROR, "Invalid segment filename template '%s'\n", s->filename);
return AVERROR(EINVAL);
}
return 0;
}
static int segment_start(AVFormatContext *s, int write_header)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc = seg->avf;
int err = 0;
if (write_header) {
avformat_free_context(oc);
seg->avf = NULL;
if ((err = segment_mux_init(s)) < 0)
return err;
oc = seg->avf;
}
seg->segment_idx++;
if ((err = set_segment_filename(s)) < 0)
return err;
seg->segment_count++;
if ((err = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
&s->interrupt_callback, NULL)) < 0)
return err;
if (oc->oformat->priv_class && oc->priv_data)
av_opt_set(oc->priv_data, "resend_headers", "1", 0); /* mpegts specific */
if (write_header) {
if ((err = avformat_write_header(oc, NULL)) < 0)
return err;
}
seg->is_first_pkt = 1;
return 0;
}
static int segment_list_open(AVFormatContext *s)
{
SegmentContext *seg = s->priv_data;
int ret;
ret = avio_open2(&seg->list_pb, seg->list, AVIO_FLAG_WRITE,
&s->interrupt_callback, NULL);
if (ret < 0)
return ret;
seg->list_max_segment_time = 0;
if (seg->list_type == LIST_TYPE_M3U8) {
avio_printf(seg->list_pb, "#EXTM3U\n");
avio_printf(seg->list_pb, "#EXT-X-VERSION:3\n");
avio_printf(seg->list_pb, "#EXT-X-MEDIA-SEQUENCE:%d\n", seg->segment_idx);
avio_printf(seg->list_pb, "#EXT-X-ALLOWCACHE:%d\n",
!!(seg->list_flags & SEGMENT_LIST_FLAG_CACHE));
if (seg->list_flags & SEGMENT_LIST_FLAG_LIVE)
avio_printf(seg->list_pb,
"#EXT-X-TARGETDURATION:%"PRId64"\n", seg->time / 1000000);
}
return ret;
}
static void segment_list_close(AVFormatContext *s)
{
SegmentContext *seg = s->priv_data;
if (seg->list_type == LIST_TYPE_M3U8) {
if (!(seg->list_flags & SEGMENT_LIST_FLAG_LIVE))
avio_printf(seg->list_pb, "#EXT-X-TARGETDURATION:%d\n",
(int)ceil(seg->list_max_segment_time));
avio_printf(seg->list_pb, "#EXT-X-ENDLIST\n");
}
avio_close(seg->list_pb);
}
static int segment_end(AVFormatContext *s, int write_trailer)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc = seg->avf;
int ret = 0;
av_write_frame(oc, NULL); /* Flush any buffered data (fragmented mp4) */
if (write_trailer)
ret = av_write_trailer(oc);
if (ret < 0)
av_log(s, AV_LOG_ERROR, "Failure occurred when ending segment '%s'\n",
oc->filename);
if (seg->list) {
if (seg->list_size && !(seg->segment_count % seg->list_size)) {
segment_list_close(s);
if ((ret = segment_list_open(s)) < 0)
goto end;
}
if (seg->list_type == LIST_TYPE_FLAT) {
avio_printf(seg->list_pb, "%s\n", oc->filename);
} else if (seg->list_type == LIST_TYPE_CSV || seg->list_type == LIST_TYPE_EXT) {
print_csv_escaped_str(seg->list_pb, oc->filename);
avio_printf(seg->list_pb, ",%f,%f\n", seg->start_time, seg->end_time);
} else if (seg->list_type == LIST_TYPE_M3U8) {
avio_printf(seg->list_pb, "#EXTINF:%f,\n%s\n",
seg->end_time - seg->start_time, oc->filename);
}
seg->list_max_segment_time = FFMAX(seg->end_time - seg->start_time, seg->list_max_segment_time);
avio_flush(seg->list_pb);
}
end:
avio_close(oc->pb);
return ret;
}
static int parse_times(void *log_ctx, int64_t **times, int *nb_times,
const char *times_str)
{
char *p;
int i, ret = 0;
char *times_str1 = av_strdup(times_str);
char *saveptr = NULL;
if (!times_str1)
return AVERROR(ENOMEM);
#define FAIL(err) ret = err; goto end
*nb_times = 1;
for (p = times_str1; *p; p++)
if (*p == ',')
(*nb_times)++;
*times = av_malloc(sizeof(**times) * *nb_times);
if (!*times) {
av_log(log_ctx, AV_LOG_ERROR, "Could not allocate forced times array\n");
FAIL(AVERROR(ENOMEM));
}
p = times_str1;
for (i = 0; i < *nb_times; i++) {
int64_t t;
char *tstr = av_strtok(p, ",", &saveptr);
p = NULL;
if (!tstr || !tstr[0]) {
av_log(log_ctx, AV_LOG_ERROR, "Empty time specification in times list %s\n",
times_str);
FAIL(AVERROR(EINVAL));
}
ret = av_parse_time(&t, tstr, 1);
if (ret < 0) {
av_log(log_ctx, AV_LOG_ERROR,
"Invalid time duration specification '%s' in times list %s\n", tstr, times_str);
FAIL(AVERROR(EINVAL));
}
(*times)[i] = t;
/* check on monotonicity */
if (i && (*times)[i-1] > (*times)[i]) {
av_log(log_ctx, AV_LOG_ERROR,
"Specified time %f is greater than the following time %f\n",
(float)((*times)[i])/1000000, (float)((*times)[i-1])/1000000);
FAIL(AVERROR(EINVAL));
}
}
end:
av_free(times_str1);
return ret;
}
static int open_null_ctx(AVIOContext **ctx)
{
int buf_size = 32768;
uint8_t *buf = av_malloc(buf_size);
if (!buf)
return AVERROR(ENOMEM);
*ctx = avio_alloc_context(buf, buf_size, AVIO_FLAG_WRITE, NULL, NULL, NULL, NULL);
if (!*ctx) {
av_free(buf);
return AVERROR(ENOMEM);
}
return 0;
}
static void close_null_ctx(AVIOContext *pb)
{
av_free(pb->buffer);
av_free(pb);
}
static int seg_write_header(AVFormatContext *s)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc = NULL;
int ret, i;
seg->segment_count = 0;
if (!seg->write_header_trailer)
seg->individual_header_trailer = 0;
if (seg->time_str && seg->times_str) {
av_log(s, AV_LOG_ERROR,
"segment_time and segment_times options are mutually exclusive, select just one of them\n");
return AVERROR(EINVAL);
}
if ((seg->list_flags & SEGMENT_LIST_FLAG_LIVE) && seg->times_str) {
av_log(s, AV_LOG_ERROR,
"segment_flags +live and segment_times options are mutually exclusive:"
"specify -segment_time if you want a live-friendly list\n");
return AVERROR(EINVAL);
}
if (seg->times_str) {
if ((ret = parse_times(s, &seg->times, &seg->nb_times, seg->times_str)) < 0)
return ret;
} else {
/* set default value if not specified */
if (!seg->time_str)
seg->time_str = av_strdup("2");
if ((ret = av_parse_time(&seg->time, seg->time_str, 1)) < 0) {
av_log(s, AV_LOG_ERROR,
"Invalid time duration specification '%s' for segment_time option\n",
seg->time_str);
return ret;
}
}
if (seg->time_delta_str) {
if ((ret = av_parse_time(&seg->time_delta, seg->time_delta_str, 1)) < 0) {
av_log(s, AV_LOG_ERROR,
"Invalid time duration specification '%s' for delta option\n",
seg->time_delta_str);
return ret;
}
}
if (seg->list) {
if (seg->list_type == LIST_TYPE_UNDEFINED) {
if (av_match_ext(seg->list, "csv" )) seg->list_type = LIST_TYPE_CSV;
else if (av_match_ext(seg->list, "ext" )) seg->list_type = LIST_TYPE_EXT;
else if (av_match_ext(seg->list, "m3u8")) seg->list_type = LIST_TYPE_M3U8;
else seg->list_type = LIST_TYPE_FLAT;
}
if ((ret = segment_list_open(s)) < 0)
goto fail;
}
if (seg->list_type == LIST_TYPE_EXT)
av_log(s, AV_LOG_WARNING, "'ext' list type option is deprecated in favor of 'csv'\n");
for (i = 0; i < s->nb_streams; i++)
seg->has_video +=
(s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO);
if (seg->has_video > 1)
av_log(s, AV_LOG_WARNING,
"More than a single video stream present, "
"expect issues decoding it.\n");
seg->oformat = av_guess_format(seg->format, s->filename, NULL);
if (!seg->oformat) {
ret = AVERROR_MUXER_NOT_FOUND;
goto fail;
}
if (seg->oformat->flags & AVFMT_NOFILE) {
av_log(s, AV_LOG_ERROR, "format %s not supported.\n",
seg->oformat->name);
ret = AVERROR(EINVAL);
goto fail;
}
if ((ret = segment_mux_init(s)) < 0)
goto fail;
oc = seg->avf;
if ((ret = set_segment_filename(s)) < 0)
goto fail;
seg->segment_count++;
if (seg->write_header_trailer) {
if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
&s->interrupt_callback, NULL)) < 0)
goto fail;
} else {
if ((ret = open_null_ctx(&oc->pb)) < 0)
goto fail;
}
if ((ret = avformat_write_header(oc, NULL)) < 0) {
avio_close(oc->pb);
goto fail;
}
seg->is_first_pkt = 1;
if (oc->avoid_negative_ts > 0 && s->avoid_negative_ts < 0)
s->avoid_negative_ts = 1;
if (!seg->write_header_trailer) {
close_null_ctx(oc->pb);
if ((ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
&s->interrupt_callback, NULL)) < 0)
goto fail;
}
fail:
if (ret) {
if (seg->list)
segment_list_close(s);
if (seg->avf)
avformat_free_context(seg->avf);
}
return ret;
}
static int seg_write_packet(AVFormatContext *s, AVPacket *pkt)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc = seg->avf;
AVStream *st = s->streams[pkt->stream_index];
int64_t end_pts;
int ret;
if (seg->times) {
end_pts = seg->segment_count <= seg->nb_times ?
seg->times[seg->segment_count-1] : INT64_MAX;
} else {
end_pts = seg->time * seg->segment_count;
}
/* if the segment has video, start a new segment *only* with a key video frame */
if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO || !seg->has_video) &&
pkt->pts != AV_NOPTS_VALUE &&
av_compare_ts(pkt->pts, st->time_base,
end_pts-seg->time_delta, AV_TIME_BASE_Q) >= 0 &&
pkt->flags & AV_PKT_FLAG_KEY) {
ret = segment_end(s, seg->individual_header_trailer);
if (!ret)
ret = segment_start(s, seg->individual_header_trailer);
if (ret)
goto fail;
oc = seg->avf;
seg->start_time = (double)pkt->pts * av_q2d(st->time_base);
seg->start_pts = av_rescale_q(pkt->pts, st->time_base, AV_TIME_BASE_Q);
seg->start_dts = pkt->dts != AV_NOPTS_VALUE ?
av_rescale_q(pkt->dts, st->time_base, AV_TIME_BASE_Q) : seg->start_pts;
} else if (pkt->pts != AV_NOPTS_VALUE) {
seg->end_time = FFMAX(seg->end_time,
(double)(pkt->pts + pkt->duration) * av_q2d(st->time_base));
}
if (seg->is_first_pkt) {
av_log(s, AV_LOG_DEBUG, "segment:'%s' starts with packet stream:%d pts:%s pts_time:%s\n",
seg->avf->filename, pkt->stream_index,
av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &st->time_base));
seg->is_first_pkt = 0;
}
if (seg->reset_timestamps) {
av_log(s, AV_LOG_DEBUG, "start_pts:%s pts:%s start_dts:%s dts:%s",
av_ts2timestr(seg->start_pts, &AV_TIME_BASE_Q), av_ts2timestr(pkt->pts, &st->time_base),
av_ts2timestr(seg->start_dts, &AV_TIME_BASE_Q), av_ts2timestr(pkt->dts, &st->time_base));
/* compute new timestamps */
if (pkt->pts != AV_NOPTS_VALUE)
pkt->pts -= av_rescale_q(seg->start_pts, AV_TIME_BASE_Q, st->time_base);
if (pkt->dts != AV_NOPTS_VALUE)
pkt->dts -= av_rescale_q(seg->start_dts, AV_TIME_BASE_Q, st->time_base);
av_log(s, AV_LOG_DEBUG, " -> pts:%s dts:%s\n",
av_ts2timestr(pkt->pts, &st->time_base), av_ts2timestr(pkt->dts, &st->time_base));
}
ret = ff_write_chained(oc, pkt->stream_index, pkt, s);
fail:
if (ret < 0) {
if (seg->list)
avio_close(seg->list_pb);
avformat_free_context(oc);
}
return ret;
}
static int seg_write_trailer(struct AVFormatContext *s)
{
SegmentContext *seg = s->priv_data;
AVFormatContext *oc = seg->avf;
int ret;
if (!seg->write_header_trailer) {
if ((ret = segment_end(s, 0)) < 0)
goto fail;
open_null_ctx(&oc->pb);
ret = av_write_trailer(oc);
close_null_ctx(oc->pb);
} else {
ret = segment_end(s, 1);
}
fail:
if (seg->list)
segment_list_close(s);
av_opt_free(seg);
av_freep(&seg->times);
avformat_free_context(oc);
return ret;
}
#define OFFSET(x) offsetof(SegmentContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "segment_format", "set container format used for the segments", OFFSET(format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
{ "segment_list", "set the segment list filename", OFFSET(list), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
{ "segment_list_flags","set flags affecting segment list generation", OFFSET(list_flags), AV_OPT_TYPE_FLAGS, {.i64 = SEGMENT_LIST_FLAG_CACHE }, 0, UINT_MAX, E, "list_flags"},
{ "cache", "allow list caching", 0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_LIST_FLAG_CACHE }, INT_MIN, INT_MAX, E, "list_flags"},
{ "live", "enable live-friendly list generation (useful for HLS)", 0, AV_OPT_TYPE_CONST, {.i64 = SEGMENT_LIST_FLAG_LIVE }, INT_MIN, INT_MAX, E, "list_flags"},
{ "segment_list_size", "set the maximum number of playlist entries", OFFSET(list_size), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
{ "segment_list_type", "set the segment list type", OFFSET(list_type), AV_OPT_TYPE_INT, {.i64 = LIST_TYPE_UNDEFINED}, -1, LIST_TYPE_NB-1, E, "list_type" },
{ "flat", "flat format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_FLAT }, INT_MIN, INT_MAX, E, "list_type" },
{ "csv", "csv format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_CSV }, INT_MIN, INT_MAX, E, "list_type" },
{ "ext", "extended format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_EXT }, INT_MIN, INT_MAX, E, "list_type" },
{ "m3u8", "M3U8 format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, E, "list_type" },
{ "hls", "Apple HTTP Live Streaming compatible", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, E, "list_type" },
{ "segment_time", "set segment duration", OFFSET(time_str),AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, E },
{ "segment_time_delta","set approximation value used for the segment times", OFFSET(time_delta_str), AV_OPT_TYPE_STRING, {.str = "0"}, 0, 0, E },
{ "segment_times", "set segment split time points", OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL}, 0, 0, E },
{ "segment_wrap", "set number after which the index wraps", OFFSET(segment_idx_wrap), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
{ "segment_start_number", "set the sequence number of the first segment", OFFSET(segment_idx), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
{ "individual_header_trailer", "write header/trailer to each segment", OFFSET(individual_header_trailer), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E },
{ "write_header_trailer", "write a header to the first segment and a trailer to the last one", OFFSET(write_header_trailer), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E },
{ "reset_timestamps", "reset timestamps at the begin of each segment", OFFSET(reset_timestamps), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, E },
{ NULL },
};
static const AVClass seg_class = {
.class_name = "segment muxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_segment_muxer = {
.name = "segment",
.long_name = NULL_IF_CONFIG_SMALL("segment"),
.priv_data_size = sizeof(SegmentContext),
.flags = AVFMT_NOFILE|AVFMT_GLOBALHEADER,
.write_header = seg_write_header,
.write_packet = seg_write_packet,
.write_trailer = seg_write_trailer,
.priv_class = &seg_class,
};
static const AVClass sseg_class = {
.class_name = "stream_segment muxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_stream_segment_muxer = {
.name = "stream_segment,ssegment",
.long_name = NULL_IF_CONFIG_SMALL("streaming segment muxer"),
.priv_data_size = sizeof(SegmentContext),
.flags = AVFMT_NOFILE,
.write_header = seg_write_header,
.write_packet = seg_write_packet,
.write_trailer = seg_write_trailer,
.priv_class = &sseg_class,
};
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