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FFmpeg/libavformat/segment.c
Stefano Sabatini 8e9056559e lavf/segment: add reset_timestamps option 
The new options reset the timestamps at each new segment, so that the
generated segments will have timestamps starting close to 0.

It is meant to address trac ticket #1425.
2012-12-11 00:18:23 +01:00

616 lines
21 KiB
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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;
} 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 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 (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);
}
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;
}
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 (av_get_frame_filename(oc->filename, sizeof(oc->filename),
s->filename, seg->segment_idx) < 0) {
ret = AVERROR(EINVAL);
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;
}
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) {
av_log(s, AV_LOG_DEBUG, "Next segment starts with packet stream:%d pts:%"PRId64" pts_time:%f\n",
pkt->stream_index, pkt->pts, pkt->pts * av_q2d(st->time_base));
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->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, 0, "list_type" },
{ "csv", "csv format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_CSV }, INT_MIN, INT_MAX, 0, "list_type" },
{ "ext", "extended format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_EXT }, INT_MIN, INT_MAX, 0, "list_type" },
{ "m3u8", "M3U8 format", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, 0, "list_type" },
{ "hls", "Apple HTTP Live Streaming compatible", 0, AV_OPT_TYPE_CONST, {.i64=LIST_TYPE_M3U8 }, INT_MIN, INT_MAX, 0, "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 },
{ "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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