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ffmpeg/libavformat/dashenc.c
Martin Storsjö b8d2630c53 dashenc: Reduce the segment duration if cutting out parts with edit lists 
This makes sure that the time + duration of the first segment
matches the start time of the next segment for e.g. AAC audio
with encoder delay.

Signed-off-by: Martin Storsjö <martin@martin.st>
2015-05-10 22:57:21 +03:00

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/*
* MPEG-DASH ISO BMFF segmenter
* Copyright (c) 2014 Martin Storsjo
*
* 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
*/
#include "config.h"
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/time_internal.h"
#include "avc.h"
#include "avformat.h"
#include "avio_internal.h"
#include "internal.h"
#include "isom.h"
#include "os_support.h"
#include "url.h"
// See ISO/IEC 23009-1:2014 5.3.9.4.4
typedef enum {
DASH_TMPL_ID_UNDEFINED = -1,
DASH_TMPL_ID_ESCAPE,
DASH_TMPL_ID_REP_ID,
DASH_TMPL_ID_NUMBER,
DASH_TMPL_ID_BANDWIDTH,
DASH_TMPL_ID_TIME,
} DASHTmplId;
typedef struct Segment {
char file[1024];
int64_t start_pos;
int range_length, index_length;
int64_t time;
int duration;
int n;
} Segment;
typedef struct OutputStream {
AVFormatContext *ctx;
int ctx_inited;
uint8_t iobuf[32768];
URLContext *out;
int packets_written;
char initfile[1024];
int64_t init_start_pos;
int init_range_length;
int nb_segments, segments_size, segment_index;
Segment **segments;
int64_t first_pts, start_pts, max_pts;
int64_t last_dts;
int bit_rate;
char bandwidth_str[64];
char codec_str[100];
} OutputStream;
typedef struct DASHContext {
const AVClass *class; /* Class for private options. */
int window_size;
int extra_window_size;
int min_seg_duration;
int remove_at_exit;
int use_template;
int use_timeline;
int single_file;
OutputStream *streams;
int has_video, has_audio;
int64_t last_duration;
int64_t total_duration;
char availability_start_time[100];
char dirname[1024];
const char *single_file_name;
const char *init_seg_name;
const char *media_seg_name;
} DASHContext;
static int dash_write(void *opaque, uint8_t *buf, int buf_size)
{
OutputStream *os = opaque;
if (os->out)
ffurl_write(os->out, buf, buf_size);
return buf_size;
}
// RFC 6381
static void set_codec_str(AVFormatContext *s, AVCodecContext *codec,
char *str, int size)
{
const AVCodecTag *tags[2] = { NULL, NULL };
uint32_t tag;
if (codec->codec_type == AVMEDIA_TYPE_VIDEO)
tags[0] = ff_codec_movvideo_tags;
else if (codec->codec_type == AVMEDIA_TYPE_AUDIO)
tags[0] = ff_codec_movaudio_tags;
else
return;
tag = av_codec_get_tag(tags, codec->codec_id);
if (!tag)
return;
if (size < 5)
return;
AV_WL32(str, tag);
str[4] = '\0';
if (!strcmp(str, "mp4a") || !strcmp(str, "mp4v")) {
uint32_t oti;
tags[0] = ff_mp4_obj_type;
oti = av_codec_get_tag(tags, codec->codec_id);
if (oti)
av_strlcatf(str, size, ".%02x", oti);
else
return;
if (tag == MKTAG('m', 'p', '4', 'a')) {
if (codec->extradata_size >= 2) {
int aot = codec->extradata[0] >> 3;
if (aot == 31)
aot = ((AV_RB16(codec->extradata) >> 5) & 0x3f) + 32;
av_strlcatf(str, size, ".%d", aot);
}
} else if (tag == MKTAG('m', 'p', '4', 'v')) {
// Unimplemented, should output ProfileLevelIndication as a decimal number
av_log(s, AV_LOG_WARNING, "Incomplete RFC 6381 codec string for mp4v\n");
}
} else if (!strcmp(str, "avc1")) {
uint8_t *tmpbuf = NULL;
uint8_t *extradata = codec->extradata;
int extradata_size = codec->extradata_size;
if (!extradata_size)
return;
if (extradata[0] != 1) {
AVIOContext *pb;
if (avio_open_dyn_buf(&pb) < 0)
return;
if (ff_isom_write_avcc(pb, extradata, extradata_size) < 0) {
ffio_free_dyn_buf(&pb);
return;
}
extradata_size = avio_close_dyn_buf(pb, &extradata);
tmpbuf = extradata;
}
if (extradata_size >= 4)
av_strlcatf(str, size, ".%02x%02x%02x",
extradata[1], extradata[2], extradata[3]);
av_free(tmpbuf);
}
}
static void dash_free(AVFormatContext *s)
{
DASHContext *c = s->priv_data;
int i, j;
if (!c->streams)
return;
for (i = 0; i < s->nb_streams; i++) {
OutputStream *os = &c->streams[i];
if (os->ctx && os->ctx_inited)
av_write_trailer(os->ctx);
if (os->ctx && os->ctx->pb)
av_free(os->ctx->pb);
ffurl_close(os->out);
os->out = NULL;
if (os->ctx)
avformat_free_context(os->ctx);
for (j = 0; j < os->nb_segments; j++)
av_free(os->segments[j]);
av_free(os->segments);
}
av_freep(&c->streams);
}
static void output_segment_list(OutputStream *os, AVIOContext *out, DASHContext *c)
{
int i, start_index = 0, start_number = 1;
if (c->window_size) {
start_index = FFMAX(os->nb_segments - c->window_size, 0);
start_number = FFMAX(os->segment_index - c->window_size, 1);
}
if (c->use_template) {
int timescale = c->use_timeline ? os->ctx->streams[0]->time_base.den : AV_TIME_BASE;
avio_printf(out, "\t\t\t\t<SegmentTemplate timescale=\"%d\" ", timescale);
if (!c->use_timeline)
avio_printf(out, "duration=\"%"PRId64"\" ", c->last_duration);
avio_printf(out, "initialization=\"%s\" media=\"%s\" startNumber=\"%d\">\n", c->init_seg_name, c->media_seg_name, c->use_timeline ? start_number : 1);
if (c->use_timeline) {
int64_t cur_time = 0;
avio_printf(out, "\t\t\t\t\t<SegmentTimeline>\n");
for (i = start_index; i < os->nb_segments; ) {
Segment *seg = os->segments[i];
int repeat = 0;
avio_printf(out, "\t\t\t\t\t\t<S ");
if (i == start_index || seg->time != cur_time) {
cur_time = seg->time;
avio_printf(out, "t=\"%"PRId64"\" ", seg->time);
}
avio_printf(out, "d=\"%d\" ", seg->duration);
while (i + repeat + 1 < os->nb_segments &&
os->segments[i + repeat + 1]->duration == seg->duration &&
os->segments[i + repeat + 1]->time == os->segments[i + repeat]->time + os->segments[i + repeat]->duration)
repeat++;
if (repeat > 0)
avio_printf(out, "r=\"%d\" ", repeat);
avio_printf(out, "/>\n");
i += 1 + repeat;
cur_time += (1 + repeat) * seg->duration;
}
avio_printf(out, "\t\t\t\t\t</SegmentTimeline>\n");
}
avio_printf(out, "\t\t\t\t</SegmentTemplate>\n");
} else if (c->single_file) {
avio_printf(out, "\t\t\t\t<BaseURL>%s</BaseURL>\n", os->initfile);
avio_printf(out, "\t\t\t\t<SegmentList timescale=\"%d\" duration=\"%"PRId64"\" startNumber=\"%d\">\n", AV_TIME_BASE, c->last_duration, start_number);
avio_printf(out, "\t\t\t\t\t<Initialization range=\"%"PRId64"-%"PRId64"\" />\n", os->init_start_pos, os->init_start_pos + os->init_range_length - 1);
for (i = start_index; i < os->nb_segments; i++) {
Segment *seg = os->segments[i];
avio_printf(out, "\t\t\t\t\t<SegmentURL mediaRange=\"%"PRId64"-%"PRId64"\" ", seg->start_pos, seg->start_pos + seg->range_length - 1);
if (seg->index_length)
avio_printf(out, "indexRange=\"%"PRId64"-%"PRId64"\" ", seg->start_pos, seg->start_pos + seg->index_length - 1);
avio_printf(out, "/>\n");
}
avio_printf(out, "\t\t\t\t</SegmentList>\n");
} else {
avio_printf(out, "\t\t\t\t<SegmentList timescale=\"%d\" duration=\"%"PRId64"\" startNumber=\"%d\">\n", AV_TIME_BASE, c->last_duration, start_number);
avio_printf(out, "\t\t\t\t\t<Initialization sourceURL=\"%s\" />\n", os->initfile);
for (i = start_index; i < os->nb_segments; i++) {
Segment *seg = os->segments[i];
avio_printf(out, "\t\t\t\t\t<SegmentURL media=\"%s\" />\n", seg->file);
}
avio_printf(out, "\t\t\t\t</SegmentList>\n");
}
}
static DASHTmplId dash_read_tmpl_id(const char *identifier, char *format_tag,
size_t format_tag_size, const char **ptr) {
const char *next_ptr;
DASHTmplId id_type = DASH_TMPL_ID_UNDEFINED;
if (av_strstart(identifier, "$$", &next_ptr)) {
id_type = DASH_TMPL_ID_ESCAPE;
*ptr = next_ptr;
} else if (av_strstart(identifier, "$RepresentationID$", &next_ptr)) {
id_type = DASH_TMPL_ID_REP_ID;
// default to basic format, as $RepresentationID$ identifiers
// are not allowed to have custom format-tags.
av_strlcpy(format_tag, "%d", format_tag_size);
*ptr = next_ptr;
} else { // the following identifiers may have an explicit format_tag
if (av_strstart(identifier, "$Number", &next_ptr))
id_type = DASH_TMPL_ID_NUMBER;
else if (av_strstart(identifier, "$Bandwidth", &next_ptr))
id_type = DASH_TMPL_ID_BANDWIDTH;
else if (av_strstart(identifier, "$Time", &next_ptr))
id_type = DASH_TMPL_ID_TIME;
else
id_type = DASH_TMPL_ID_UNDEFINED;
// next parse the dash format-tag and generate a c-string format tag
// (next_ptr now points at the first '%' at the beginning of the format-tag)
if (id_type != DASH_TMPL_ID_UNDEFINED) {
const char *number_format = (id_type == DASH_TMPL_ID_TIME) ? PRId64 : "d";
if (next_ptr[0] == '$') { // no dash format-tag
snprintf(format_tag, format_tag_size, "%%%s", number_format);
*ptr = &next_ptr[1];
} else {
const char *width_ptr;
// only tolerate single-digit width-field (i.e. up to 9-digit width)
if (av_strstart(next_ptr, "%0", &width_ptr) &&
av_isdigit(width_ptr[0]) &&
av_strstart(&width_ptr[1], "d$", &next_ptr)) {
// yes, we're using a format tag to build format_tag.
snprintf(format_tag, format_tag_size, "%s%c%s", "%0", width_ptr[0], number_format);
*ptr = next_ptr;
} else {
av_log(NULL, AV_LOG_WARNING, "Failed to parse format-tag beginning with %s. Expected either a "
"closing '$' character or a format-string like '%%0[width]d', "
"where width must be a single digit\n", next_ptr);
id_type = DASH_TMPL_ID_UNDEFINED;
}
}
}
}
return id_type;
}
static void dash_fill_tmpl_params(char *dst, size_t buffer_size,
const char *template, int rep_id,
int number, int bit_rate,
int64_t time) {
int dst_pos = 0;
const char *t_cur = template;
while (dst_pos < buffer_size - 1 && *t_cur) {
char format_tag[7]; // May be "%d", "%0Xd", or "%0Xlld" (for $Time$), where X is in [0-9]
int n = 0;
DASHTmplId id_type;
const char *t_next = strchr(t_cur, '$'); // copy over everything up to the first '$' character
if (t_next) {
int num_copy_bytes = FFMIN(t_next - t_cur, buffer_size - dst_pos - 1);
av_strlcpy(&dst[dst_pos], t_cur, num_copy_bytes + 1);
// advance
dst_pos += num_copy_bytes;
t_cur = t_next;
} else { // no more DASH identifiers to substitute - just copy the rest over and break
av_strlcpy(&dst[dst_pos], t_cur, buffer_size - dst_pos);
break;
}
if (dst_pos >= buffer_size - 1 || !*t_cur)
break;
// t_cur is now pointing to a '$' character
id_type = dash_read_tmpl_id(t_cur, format_tag, sizeof(format_tag), &t_next);
switch (id_type) {
case DASH_TMPL_ID_ESCAPE:
av_strlcpy(&dst[dst_pos], "$", 2);
n = 1;
break;
case DASH_TMPL_ID_REP_ID:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, rep_id);
break;
case DASH_TMPL_ID_NUMBER:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, number);
break;
case DASH_TMPL_ID_BANDWIDTH:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, bit_rate);
break;
case DASH_TMPL_ID_TIME:
n = snprintf(&dst[dst_pos], buffer_size - dst_pos, format_tag, time);
break;
case DASH_TMPL_ID_UNDEFINED:
// copy over one byte and advance
av_strlcpy(&dst[dst_pos], t_cur, 2);
n = 1;
t_next = &t_cur[1];
break;
}
// t_next points just past the processed identifier
// n is the number of bytes that were attempted to be written to dst
// (may have failed to write all because buffer_size).
// advance
dst_pos += FFMIN(n, buffer_size - dst_pos - 1);
t_cur = t_next;
}
}
static char *xmlescape(const char *str) {
int outlen = strlen(str)*3/2 + 6;
char *out = av_realloc(NULL, outlen + 1);
int pos = 0;
if (!out)
return NULL;
for (; *str; str++) {
if (pos + 6 > outlen) {
char *tmp;
outlen = 2 * outlen + 6;
tmp = av_realloc(out, outlen + 1);
if (!tmp) {
av_free(out);
return NULL;
}
out = tmp;
}
if (*str == '&') {
memcpy(&out[pos], "&amp;", 5);
pos += 5;
} else if (*str == '<') {
memcpy(&out[pos], "&lt;", 4);
pos += 4;
} else if (*str == '>') {
memcpy(&out[pos], "&gt;", 4);
pos += 4;
} else if (*str == '\'') {
memcpy(&out[pos], "&apos;", 6);
pos += 6;
} else if (*str == '\"') {
memcpy(&out[pos], "&quot;", 6);
pos += 6;
} else {
out[pos++] = *str;
}
}
out[pos] = '\0';
return out;
}
static void write_time(AVIOContext *out, int64_t time)
{
int seconds = time / AV_TIME_BASE;
int fractions = time % AV_TIME_BASE;
int minutes = seconds / 60;
int hours = minutes / 60;
seconds %= 60;
minutes %= 60;
avio_printf(out, "PT");
if (hours)
avio_printf(out, "%dH", hours);
if (hours || minutes)
avio_printf(out, "%dM", minutes);
avio_printf(out, "%d.%dS", seconds, fractions / (AV_TIME_BASE / 10));
}
static void format_date_now(char *buf, int size)
{
time_t t = time(NULL);
struct tm *ptm, tmbuf;
ptm = gmtime_r(&t, &tmbuf);
if (ptm) {
if (!strftime(buf, size, "%Y-%m-%dT%H:%M:%S", ptm))
buf[0] = '\0';
}
}
static int write_manifest(AVFormatContext *s, int final)
{
DASHContext *c = s->priv_data;
AVIOContext *out;
char temp_filename[1024];
int ret, i;
AVDictionaryEntry *title = av_dict_get(s->metadata, "title", NULL, 0);
snprintf(temp_filename, sizeof(temp_filename), "%s.tmp", s->filename);
ret = avio_open2(&out, temp_filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n", temp_filename);
return ret;
}
avio_printf(out, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
avio_printf(out, "<MPD xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
"\txmlns=\"urn:mpeg:dash:schema:mpd:2011\"\n"
"\txmlns:xlink=\"http://www.w3.org/1999/xlink\"\n"
"\txsi:schemaLocation=\"urn:mpeg:DASH:schema:MPD:2011 http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-DASH_schema_files/DASH-MPD.xsd\"\n"
"\tprofiles=\"urn:mpeg:dash:profile:isoff-live:2011\"\n"
"\ttype=\"%s\"\n", final ? "static" : "dynamic");
if (final) {
avio_printf(out, "\tmediaPresentationDuration=\"");
write_time(out, c->total_duration);
avio_printf(out, "\"\n");
} else {
int64_t update_period = c->last_duration / AV_TIME_BASE;
char now_str[100];
if (c->use_template && !c->use_timeline)
update_period = 500;
avio_printf(out, "\tminimumUpdatePeriod=\"PT%"PRId64"S\"\n", update_period);
avio_printf(out, "\tsuggestedPresentationDelay=\"PT%"PRId64"S\"\n", c->last_duration / AV_TIME_BASE);
if (!c->availability_start_time[0] && s->nb_streams > 0 && c->streams[0].nb_segments > 0) {
format_date_now(c->availability_start_time, sizeof(c->availability_start_time));
}
if (c->availability_start_time[0])
avio_printf(out, "\tavailabilityStartTime=\"%s\"\n", c->availability_start_time);
format_date_now(now_str, sizeof(now_str));
if (now_str[0])
avio_printf(out, "\tpublishTime=\"%s\"\n", now_str);
if (c->window_size && c->use_template) {
avio_printf(out, "\ttimeShiftBufferDepth=\"");
write_time(out, c->last_duration * c->window_size);
avio_printf(out, "\"\n");
}
}
avio_printf(out, "\tminBufferTime=\"");
write_time(out, c->last_duration);
avio_printf(out, "\">\n");
avio_printf(out, "\t<ProgramInformation>\n");
if (title) {
char *escaped = xmlescape(title->value);
avio_printf(out, "\t\t<Title>%s</Title>\n", escaped);
av_free(escaped);
}
avio_printf(out, "\t</ProgramInformation>\n");
if (c->window_size && s->nb_streams > 0 && c->streams[0].nb_segments > 0 && !c->use_template) {
OutputStream *os = &c->streams[0];
int start_index = FFMAX(os->nb_segments - c->window_size, 0);
int64_t start_time = av_rescale_q(os->segments[start_index]->time, s->streams[0]->time_base, AV_TIME_BASE_Q);
avio_printf(out, "\t<Period start=\"");
write_time(out, start_time);
avio_printf(out, "\">\n");
} else {
avio_printf(out, "\t<Period start=\"PT0.0S\">\n");
}
if (c->has_video) {
avio_printf(out, "\t\t<AdaptationSet contentType=\"video\" segmentAlignment=\"true\" bitstreamSwitching=\"true\">\n");
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
OutputStream *os = &c->streams[i];
if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO)
continue;
avio_printf(out, "\t\t\t<Representation id=\"%d\" mimeType=\"video/mp4\" codecs=\"%s\"%s width=\"%d\" height=\"%d\">\n", i, os->codec_str, os->bandwidth_str, st->codec->width, st->codec->height);
output_segment_list(&c->streams[i], out, c);
avio_printf(out, "\t\t\t</Representation>\n");
}
avio_printf(out, "\t\t</AdaptationSet>\n");
}
if (c->has_audio) {
avio_printf(out, "\t\t<AdaptationSet contentType=\"audio\" segmentAlignment=\"true\" bitstreamSwitching=\"true\">\n");
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
OutputStream *os = &c->streams[i];
if (st->codec->codec_type != AVMEDIA_TYPE_AUDIO)
continue;
avio_printf(out, "\t\t\t<Representation id=\"%d\" mimeType=\"audio/mp4\" codecs=\"%s\"%s audioSamplingRate=\"%d\">\n", i, os->codec_str, os->bandwidth_str, st->codec->sample_rate);
avio_printf(out, "\t\t\t\t<AudioChannelConfiguration schemeIdUri=\"urn:mpeg:dash:23003:3:audio_channel_configuration:2011\" value=\"%d\" />\n", st->codec->channels);
output_segment_list(&c->streams[i], out, c);
avio_printf(out, "\t\t\t</Representation>\n");
}
avio_printf(out, "\t\t</AdaptationSet>\n");
}
avio_printf(out, "\t</Period>\n");
avio_printf(out, "</MPD>\n");
avio_flush(out);
avio_close(out);
return ff_rename(temp_filename, s->filename);
}
static int dash_write_header(AVFormatContext *s)
{
DASHContext *c = s->priv_data;
int ret = 0, i;
AVOutputFormat *oformat;
char *ptr;
char basename[1024];
if (c->single_file_name)
c->single_file = 1;
if (c->single_file)
c->use_template = 0;
av_strlcpy(c->dirname, s->filename, sizeof(c->dirname));
ptr = strrchr(c->dirname, '/');
if (ptr) {
av_strlcpy(basename, &ptr[1], sizeof(basename));
ptr[1] = '\0';
} else {
c->dirname[0] = '\0';
av_strlcpy(basename, s->filename, sizeof(basename));
}
ptr = strrchr(basename, '.');
if (ptr)
*ptr = '\0';
oformat = av_guess_format("mp4", NULL, NULL);
if (!oformat) {
ret = AVERROR_MUXER_NOT_FOUND;
goto fail;
}
c->streams = av_mallocz(sizeof(*c->streams) * s->nb_streams);
if (!c->streams) {
ret = AVERROR(ENOMEM);
goto fail;
}
for (i = 0; i < s->nb_streams; i++) {
OutputStream *os = &c->streams[i];
AVFormatContext *ctx;
AVStream *st;
AVDictionary *opts = NULL;
char filename[1024];
os->bit_rate = s->streams[i]->codec->bit_rate;
if (os->bit_rate) {
snprintf(os->bandwidth_str, sizeof(os->bandwidth_str),
" bandwidth=\"%d\"", os->bit_rate);
} else {
int level = s->strict_std_compliance >= FF_COMPLIANCE_STRICT ?
AV_LOG_ERROR : AV_LOG_WARNING;
av_log(s, level, "No bit rate set for stream %d\n", i);
if (s->strict_std_compliance >= FF_COMPLIANCE_STRICT) {
ret = AVERROR(EINVAL);
goto fail;
}
}
ctx = avformat_alloc_context();
if (!ctx) {
ret = AVERROR(ENOMEM);
goto fail;
}
os->ctx = ctx;
ctx->oformat = oformat;
ctx->interrupt_callback = s->interrupt_callback;
if (!(st = avformat_new_stream(ctx, NULL))) {
ret = AVERROR(ENOMEM);
goto fail;
}
avcodec_copy_context(st->codec, s->streams[i]->codec);
st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
st->time_base = s->streams[i]->time_base;
ctx->avoid_negative_ts = s->avoid_negative_ts;
ctx->pb = avio_alloc_context(os->iobuf, sizeof(os->iobuf), AVIO_FLAG_WRITE, os, NULL, dash_write, NULL);
if (!ctx->pb) {
ret = AVERROR(ENOMEM);
goto fail;
}
if (c->single_file) {
if (c->single_file_name)
dash_fill_tmpl_params(os->initfile, sizeof(os->initfile), c->single_file_name, i, 0, os->bit_rate, 0);
else
snprintf(os->initfile, sizeof(os->initfile), "%s-stream%d.m4s", basename, i);
} else {
dash_fill_tmpl_params(os->initfile, sizeof(os->initfile), c->init_seg_name, i, 0, os->bit_rate, 0);
}
snprintf(filename, sizeof(filename), "%s%s", c->dirname, os->initfile);
ret = ffurl_open(&os->out, filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
if (ret < 0)
goto fail;
os->init_start_pos = 0;
av_dict_set(&opts, "movflags", "frag_custom+dash+delay_moov", 0);
if ((ret = avformat_write_header(ctx, &opts)) < 0) {
goto fail;
}
os->ctx_inited = 1;
avio_flush(ctx->pb);
av_dict_free(&opts);
av_log(s, AV_LOG_VERBOSE, "Representation %d init segment will be written to: %s\n", i, filename);
s->streams[i]->time_base = st->time_base;
// If the muxer wants to shift timestamps, request to have them shifted
// already before being handed to this muxer, so we don't have mismatches
// between the MPD and the actual segments.
s->avoid_negative_ts = ctx->avoid_negative_ts;
if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
c->has_video = 1;
else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
c->has_audio = 1;
set_codec_str(s, st->codec, os->codec_str, sizeof(os->codec_str));
os->first_pts = AV_NOPTS_VALUE;
os->max_pts = AV_NOPTS_VALUE;
os->last_dts = AV_NOPTS_VALUE;
os->segment_index = 1;
}
if (!c->has_video && c->min_seg_duration <= 0) {
av_log(s, AV_LOG_WARNING, "no video stream and no min seg duration set\n");
ret = AVERROR(EINVAL);
}
ret = write_manifest(s, 0);
if (!ret)
av_log(s, AV_LOG_VERBOSE, "Manifest written to: %s\n", s->filename);
fail:
if (ret)
dash_free(s);
return ret;
}
static int add_segment(OutputStream *os, const char *file,
int64_t time, int duration,
int64_t start_pos, int64_t range_length,
int64_t index_length)
{
int err;
Segment *seg;
if (os->nb_segments >= os->segments_size) {
os->segments_size = (os->segments_size + 1) * 2;
if ((err = av_reallocp(&os->segments, sizeof(*os->segments) *
os->segments_size)) < 0) {
os->segments_size = 0;
os->nb_segments = 0;
return err;
}
}
seg = av_mallocz(sizeof(*seg));
if (!seg)
return AVERROR(ENOMEM);
av_strlcpy(seg->file, file, sizeof(seg->file));
seg->time = time;
seg->duration = duration;
if (seg->time < 0) { // If pts<0, it is expected to be cut away with an edit list
seg->duration += seg->time;
seg->time = 0;
}
seg->start_pos = start_pos;
seg->range_length = range_length;
seg->index_length = index_length;
os->segments[os->nb_segments++] = seg;
os->segment_index++;
return 0;
}
static void write_styp(AVIOContext *pb)
{
avio_wb32(pb, 24);
ffio_wfourcc(pb, "styp");
ffio_wfourcc(pb, "msdh");
avio_wb32(pb, 0); /* minor */
ffio_wfourcc(pb, "msdh");
ffio_wfourcc(pb, "msix");
}
static void find_index_range(AVFormatContext *s, const char *full_path,
int64_t pos, int *index_length)
{
uint8_t buf[8];
URLContext *fd;
int ret;
ret = ffurl_open(&fd, full_path, AVIO_FLAG_READ, &s->interrupt_callback, NULL);
if (ret < 0)
return;
if (ffurl_seek(fd, pos, SEEK_SET) != pos) {
ffurl_close(fd);
return;
}
ret = ffurl_read(fd, buf, 8);
ffurl_close(fd);
if (ret < 8)
return;
if (AV_RL32(&buf[4]) != MKTAG('s', 'i', 'd', 'x'))
return;
*index_length = AV_RB32(&buf[0]);
}
static int update_stream_extradata(AVFormatContext *s, OutputStream *os,
AVCodecContext *codec)
{
uint8_t *extradata;
if (os->ctx->streams[0]->codec->extradata_size || !codec->extradata_size)
return 0;
extradata = av_malloc(codec->extradata_size);
if (!extradata)
return AVERROR(ENOMEM);
memcpy(extradata, codec->extradata, codec->extradata_size);
os->ctx->streams[0]->codec->extradata = extradata;
os->ctx->streams[0]->codec->extradata_size = codec->extradata_size;
set_codec_str(s, codec, os->codec_str, sizeof(os->codec_str));
return 0;
}
static int dash_flush(AVFormatContext *s, int final, int stream)
{
DASHContext *c = s->priv_data;
int i, ret = 0;
int cur_flush_segment_index = 0;
if (stream >= 0)
cur_flush_segment_index = c->streams[stream].segment_index;
for (i = 0; i < s->nb_streams; i++) {
OutputStream *os = &c->streams[i];
char filename[1024] = "", full_path[1024], temp_path[1024];
int64_t start_pos;
int range_length, index_length = 0;
if (!os->packets_written)
continue;
// Flush the single stream that got a keyframe right now.
// Flush all audio streams as well, in sync with video keyframes,
// but not the other video streams.
if (stream >= 0 && i != stream) {
if (s->streams[i]->codec->codec_type != AVMEDIA_TYPE_AUDIO)
continue;
// Make sure we don't flush audio streams multiple times, when
// all video streams are flushed one at a time.
if (c->has_video && os->segment_index > cur_flush_segment_index)
continue;
}
if (!os->init_range_length) {
av_write_frame(os->ctx, NULL);
os->init_range_length = avio_tell(os->ctx->pb);
if (!c->single_file) {
ffurl_close(os->out);
os->out = NULL;
}
}
start_pos = avio_tell(os->ctx->pb);
if (!c->single_file) {
dash_fill_tmpl_params(filename, sizeof(filename), c->media_seg_name, i, os->segment_index, os->bit_rate, os->start_pts);
snprintf(full_path, sizeof(full_path), "%s%s", c->dirname, filename);
snprintf(temp_path, sizeof(temp_path), "%s.tmp", full_path);
ret = ffurl_open(&os->out, temp_path, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
if (ret < 0)
break;
write_styp(os->ctx->pb);
} else {
snprintf(full_path, sizeof(full_path), "%s%s", c->dirname, os->initfile);
}
av_write_frame(os->ctx, NULL);
avio_flush(os->ctx->pb);
os->packets_written = 0;
range_length = avio_tell(os->ctx->pb) - start_pos;
if (c->single_file) {
find_index_range(s, full_path, start_pos, &index_length);
} else {
ffurl_close(os->out);
os->out = NULL;
ret = ff_rename(temp_path, full_path);
if (ret < 0)
break;
}
add_segment(os, filename, os->start_pts, os->max_pts - os->start_pts, start_pos, range_length, index_length);
av_log(s, AV_LOG_VERBOSE, "Representation %d media segment %d written to: %s\n", i, os->segment_index, full_path);
}
if (c->window_size || (final && c->remove_at_exit)) {
for (i = 0; i < s->nb_streams; i++) {
OutputStream *os = &c->streams[i];
int j;
int remove = os->nb_segments - c->window_size - c->extra_window_size;
if (final && c->remove_at_exit)
remove = os->nb_segments;
if (remove > 0) {
for (j = 0; j < remove; j++) {
char filename[1024];
snprintf(filename, sizeof(filename), "%s%s", c->dirname, os->segments[j]->file);
unlink(filename);
av_free(os->segments[j]);
}
os->nb_segments -= remove;
memmove(os->segments, os->segments + remove, os->nb_segments * sizeof(*os->segments));
}
}
}
if (ret >= 0)
ret = write_manifest(s, final);
return ret;
}
static int dash_write_packet(AVFormatContext *s, AVPacket *pkt)
{
DASHContext *c = s->priv_data;
AVStream *st = s->streams[pkt->stream_index];
OutputStream *os = &c->streams[pkt->stream_index];
int64_t seg_end_duration = (os->segment_index) * (int64_t) c->min_seg_duration;
int ret;
ret = update_stream_extradata(s, os, st->codec);
if (ret < 0)
return ret;
// Fill in a heuristic guess of the packet duration, if none is available.
// The mp4 muxer will do something similar (for the last packet in a fragment)
// if nothing is set (setting it for the other packets doesn't hurt).
// By setting a nonzero duration here, we can be sure that the mp4 muxer won't
// invoke its heuristic (this doesn't have to be identical to that algorithm),
// so that we know the exact timestamps of fragments.
if (!pkt->duration && os->last_dts != AV_NOPTS_VALUE)
pkt->duration = pkt->dts - os->last_dts;
os->last_dts = pkt->dts;
// If forcing the stream to start at 0, the mp4 muxer will set the start
// timestamps to 0. Do the same here, to avoid mismatches in duration/timestamps.
if (os->first_pts == AV_NOPTS_VALUE &&
s->avoid_negative_ts == AVFMT_AVOID_NEG_TS_MAKE_ZERO) {
pkt->pts -= pkt->dts;
pkt->dts = 0;
}
if (os->first_pts == AV_NOPTS_VALUE)
os->first_pts = pkt->pts;
if ((!c->has_video || st->codec->codec_type == AVMEDIA_TYPE_VIDEO) &&
pkt->flags & AV_PKT_FLAG_KEY && os->packets_written &&
av_compare_ts(pkt->pts - os->first_pts, st->time_base,
seg_end_duration, AV_TIME_BASE_Q) >= 0) {
int64_t prev_duration = c->last_duration;
c->last_duration = av_rescale_q(pkt->pts - os->start_pts,
st->time_base,
AV_TIME_BASE_Q);
c->total_duration = av_rescale_q(pkt->pts - os->first_pts,
st->time_base,
AV_TIME_BASE_Q);
if ((!c->use_timeline || !c->use_template) && prev_duration) {
if (c->last_duration < prev_duration*9/10 ||
c->last_duration > prev_duration*11/10) {
av_log(s, AV_LOG_WARNING,
"Segment durations differ too much, enable use_timeline "
"and use_template, or keep a stricter keyframe interval\n");
}
}
if ((ret = dash_flush(s, 0, pkt->stream_index)) < 0)
return ret;
}
if (!os->packets_written) {
// If we wrote a previous segment, adjust the start time of the segment
// to the end of the previous one (which is the same as the mp4 muxer
// does). This avoids gaps in the timeline.
if (os->max_pts != AV_NOPTS_VALUE)
os->start_pts = os->max_pts;
else
os->start_pts = pkt->pts;
}
if (os->max_pts == AV_NOPTS_VALUE)
os->max_pts = pkt->pts + pkt->duration;
else
os->max_pts = FFMAX(os->max_pts, pkt->pts + pkt->duration);
os->packets_written++;
return ff_write_chained(os->ctx, 0, pkt, s);
}
static int dash_write_trailer(AVFormatContext *s)
{
DASHContext *c = s->priv_data;
if (s->nb_streams > 0) {
OutputStream *os = &c->streams[0];
// If no segments have been written so far, try to do a crude
// guess of the segment duration
if (!c->last_duration)
c->last_duration = av_rescale_q(os->max_pts - os->start_pts,
s->streams[0]->time_base,
AV_TIME_BASE_Q);
c->total_duration = av_rescale_q(os->max_pts - os->first_pts,
s->streams[0]->time_base,
AV_TIME_BASE_Q);
}
dash_flush(s, 1, -1);
if (c->remove_at_exit) {
char filename[1024];
int i;
for (i = 0; i < s->nb_streams; i++) {
OutputStream *os = &c->streams[i];
snprintf(filename, sizeof(filename), "%s%s", c->dirname, os->initfile);
unlink(filename);
}
unlink(s->filename);
}
dash_free(s);
return 0;
}
#define OFFSET(x) offsetof(DASHContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "window_size", "number of segments kept in the manifest", OFFSET(window_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, E },
{ "extra_window_size", "number of segments kept outside of the manifest before removing from disk", OFFSET(extra_window_size), AV_OPT_TYPE_INT, { .i64 = 5 }, 0, INT_MAX, E },
{ "min_seg_duration", "minimum segment duration (in microseconds)", OFFSET(min_seg_duration), AV_OPT_TYPE_INT64, { .i64 = 5000000 }, 0, INT_MAX, E },
{ "remove_at_exit", "remove all segments when finished", OFFSET(remove_at_exit), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, E },
{ "use_template", "Use SegmentTemplate instead of SegmentList", OFFSET(use_template), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, E },
{ "use_timeline", "Use SegmentTimeline in SegmentTemplate", OFFSET(use_timeline), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, E },
{ "single_file", "Store all segments in one file, accessed using byte ranges", OFFSET(single_file), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, E },
{ "single_file_name", "DASH-templated name to be used for baseURL. Implies storing all segments in one file, accessed using byte ranges", OFFSET(single_file_name), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
{ "init_seg_name", "DASH-templated name to used for the initialization segment", OFFSET(init_seg_name), AV_OPT_TYPE_STRING, {.str = "init-stream$RepresentationID$.m4s"}, 0, 0, E },
{ "media_seg_name", "DASH-templated name to used for the media segments", OFFSET(media_seg_name), AV_OPT_TYPE_STRING, {.str = "chunk-stream$RepresentationID$-$Number%05d$.m4s"}, 0, 0, E },
{ NULL },
};
static const AVClass dash_class = {
.class_name = "dash muxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_dash_muxer = {
.name = "dash",
.long_name = NULL_IF_CONFIG_SMALL("DASH Muxer"),
.priv_data_size = sizeof(DASHContext),
.audio_codec = AV_CODEC_ID_AAC,
.video_codec = AV_CODEC_ID_H264,
.flags = AVFMT_GLOBALHEADER | AVFMT_NOFILE | AVFMT_TS_NEGATIVE,
.write_header = dash_write_header,
.write_packet = dash_write_packet,
.write_trailer = dash_write_trailer,
.codec_tag = (const AVCodecTag* const []){ ff_mp4_obj_type, 0 },
.priv_class = &dash_class,
};
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