ffmpeg/libavformat/webmdashenc.c

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/*
* WebM DASH Manifest XML muxer
* Copyright (c) 2014 Vignesh Venkatasubramanian
*
* 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
*/
/*
* WebM DASH Specification:
* https://sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification
*/
#include <stdint.h>
#include <string.h>
#include "avformat.h"
#include "avio_internal.h"
#include "matroska.h"
#include "libavutil/avstring.h"
#include "libavutil/dict.h"
#include "libavutil/opt.h"
typedef struct AdaptationSet {
char id[10];
int *streams;
int nb_streams;
} AdaptationSet;
typedef struct WebMDashMuxContext {
const AVClass *class;
char *adaptation_sets;
AdaptationSet *as;
int nb_as;
} WebMDashMuxContext;
static const char *get_codec_name(int codec_id)
{
switch (codec_id) {
case AV_CODEC_ID_VP8:
return "vp8";
case AV_CODEC_ID_VP9:
return "vp9";
case AV_CODEC_ID_VORBIS:
return "vorbis";
case AV_CODEC_ID_OPUS:
return "opus";
}
return NULL;
}
static double get_duration(AVFormatContext *s)
{
int i = 0;
double max = 0.0;
for (i = 0; i < s->nb_streams; i++) {
AVDictionaryEntry *duration = av_dict_get(s->streams[i]->metadata,
DURATION, NULL, 0);
if (duration == NULL || atof(duration->value) < 0) continue;
if (atof(duration->value) > max) max = atof(duration->value);
}
return max / 1000;
}
static void write_header(AVFormatContext *s)
{
double min_buffer_time = 1.0;
avio_printf(s->pb, "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
avio_printf(s->pb, "<MPD\n");
avio_printf(s->pb, " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n");
avio_printf(s->pb, " xmlns=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
avio_printf(s->pb, " xsi:schemaLocation=\"urn:mpeg:DASH:schema:MPD:2011\"\n");
avio_printf(s->pb, " type=\"static\"\n");
avio_printf(s->pb, " mediaPresentationDuration=\"PT%gS\"\n",
get_duration(s));
avio_printf(s->pb, " minBufferTime=\"PT%gS\"\n",
min_buffer_time);
avio_printf(s->pb, " profiles=\"urn:webm:dash:profile:webm-on-demand:2012\"");
avio_printf(s->pb, ">\n");
}
static void write_footer(AVFormatContext *s)
{
avio_printf(s->pb, "</MPD>");
}
static int subsegment_alignment(AVFormatContext *s, AdaptationSet *as) {
int i;
AVDictionaryEntry *gold = av_dict_get(s->streams[as->streams[0]]->metadata,
CUE_TIMESTAMPS, NULL, 0);
if (gold == NULL) return 0;
for (i = 1; i < as->nb_streams; i++) {
AVDictionaryEntry *ts = av_dict_get(s->streams[as->streams[i]]->metadata,
CUE_TIMESTAMPS, NULL, 0);
if (ts == NULL || strncmp(gold->value, ts->value, strlen(gold->value))) return 0;
}
return 1;
}
static int bitstream_switching(AVFormatContext *s, AdaptationSet *as) {
int i;
AVDictionaryEntry *gold_track_num = av_dict_get(s->streams[as->streams[0]]->metadata,
TRACK_NUMBER, NULL, 0);
AVCodecContext *gold_codec = s->streams[as->streams[0]]->codec;
if (gold_track_num == NULL) return 0;
for (i = 1; i < as->nb_streams; i++) {
AVDictionaryEntry *track_num = av_dict_get(s->streams[as->streams[i]]->metadata,
TRACK_NUMBER, NULL, 0);
AVCodecContext *codec = s->streams[as->streams[i]]->codec;
if (track_num == NULL ||
strncmp(gold_track_num->value, track_num->value, strlen(gold_track_num->value)) ||
gold_codec->codec_id != codec->codec_id ||
gold_codec->extradata_size != codec->extradata_size ||
memcmp(gold_codec->extradata, codec->extradata, codec->extradata_size)) {
return 0;
}
}
return 1;
}
/*
* Writes an Adaptation Set. Returns 0 on success and < 0 on failure.
*/
static int write_adaptation_set(AVFormatContext *s, int as_index)
{
WebMDashMuxContext *w = s->priv_data;
AdaptationSet *as = &w->as[as_index];
AVCodecContext *codec = s->streams[as->streams[0]]->codec;
int i;
static const char boolean[2][6] = { "false", "true" };
int subsegmentStartsWithSAP = 1;
AVDictionaryEntry *lang;
avio_printf(s->pb, "<AdaptationSet id=\"%s\"", as->id);
avio_printf(s->pb, " mimeType=\"%s/webm\"",
codec->codec_type == AVMEDIA_TYPE_VIDEO ? "video" : "audio");
avio_printf(s->pb, " codecs=\"%s\"", get_codec_name(codec->codec_id));
lang = av_dict_get(s->streams[as->streams[0]]->metadata, "language", NULL, 0);
if (lang != NULL) avio_printf(s->pb, " lang=\"%s\"", lang->value);
if (codec->codec_type == AVMEDIA_TYPE_VIDEO) {
avio_printf(s->pb, " width=\"%d\"", codec->width);
avio_printf(s->pb, " height=\"%d\"", codec->height);
} else {
avio_printf(s->pb, " audioSamplingRate=\"%d\"", codec->sample_rate);
}
avio_printf(s->pb, " bitstreamSwitching=\"%s\"",
boolean[bitstream_switching(s, as)]);
avio_printf(s->pb, " subsegmentAlignment=\"%s\"",
boolean[subsegment_alignment(s, as)]);
for (i = 0; i < as->nb_streams; i++) {
AVDictionaryEntry *kf = av_dict_get(s->streams[as->streams[i]]->metadata,
CLUSTER_KEYFRAME, NULL, 0);
if (kf == NULL || !strncmp(kf->value, "0", 1)) subsegmentStartsWithSAP = 0;
}
avio_printf(s->pb, " subsegmentStartsWithSAP=\"%d\"", subsegmentStartsWithSAP);
avio_printf(s->pb, ">\n");
for (i = 0; i < as->nb_streams; i++) {
AVStream *stream = s->streams[as->streams[i]];
AVDictionaryEntry *irange = av_dict_get(stream->metadata, INITIALIZATION_RANGE, NULL, 0);
AVDictionaryEntry *cues_start = av_dict_get(stream->metadata, CUES_START, NULL, 0);
AVDictionaryEntry *cues_end = av_dict_get(stream->metadata, CUES_END, NULL, 0);
AVDictionaryEntry *filename = av_dict_get(stream->metadata, FILENAME, NULL, 0);
AVDictionaryEntry *bandwidth = av_dict_get(stream->metadata, BANDWIDTH, NULL, 0);
if (irange == NULL || cues_start == NULL || cues_end == NULL || filename == NULL ||
bandwidth == NULL) {
return -1;
}
avio_printf(s->pb, "<Representation id=\"%d\"", i);
avio_printf(s->pb, " bandwidth=\"%s\"", bandwidth->value);
avio_printf(s->pb, ">\n");
avio_printf(s->pb, "<BaseURL>%s</BaseURL>\n", filename->value);
avio_printf(s->pb, "<SegmentBase\n");
avio_printf(s->pb, " indexRange=\"%s-%s\">\n", cues_start->value, cues_end->value);
avio_printf(s->pb, "<Initialization\n");
avio_printf(s->pb, " range=\"0-%s\" />\n", irange->value);
avio_printf(s->pb, "</SegmentBase>\n");
avio_printf(s->pb, "</Representation>\n");
}
avio_printf(s->pb, "</AdaptationSet>\n");
return 0;
}
static int to_integer(char *p, int len)
{
int ret;
char *q = av_malloc(sizeof(char) * len);
if (q == NULL) return -1;
strncpy(q, p, len);
ret = atoi(q);
av_free(q);
return ret;
}
static int parse_adaptation_sets(AVFormatContext *s)
{
WebMDashMuxContext *w = s->priv_data;
char *p = w->adaptation_sets;
char *q;
enum { new_set, parsed_id, parsing_streams } state;
// syntax id=0,streams=0,1,2 id=1,streams=3,4 and so on
state = new_set;
while (p < w->adaptation_sets + strlen(w->adaptation_sets)) {
if (*p == ' ')
continue;
else if (state == new_set && !strncmp(p, "id=", 3)) {
w->as = av_realloc(w->as, sizeof(*w->as) * ++w->nb_as);
if (w->as == NULL) return -1;
w->as[w->nb_as - 1].nb_streams = 0;
w->as[w->nb_as - 1].streams = NULL;
p += 3; // consume "id="
q = w->as[w->nb_as - 1].id;
while (*p != ',') *q++ = *p++;
*q = 0;
p++;
state = parsed_id;
} else if (state == parsed_id && !strncmp(p, "streams=", 8)) {
p += 8; // consume "streams="
state = parsing_streams;
} else if (state == parsing_streams) {
struct AdaptationSet *as = &w->as[w->nb_as - 1];
q = p;
while (*q != '\0' && *q != ',' && *q != ' ') q++;
as->streams = av_realloc(as->streams, sizeof(*as->streams) * ++as->nb_streams);
if (as->streams == NULL) return -1;
as->streams[as->nb_streams - 1] = to_integer(p, q - p);
if (as->streams[as->nb_streams - 1] < 0) return -1;
if (*q == '\0') break;
if (*q == ' ') state = new_set;
p = ++q;
} else {
return -1;
}
}
return 0;
}
static int webm_dash_manifest_write_header(AVFormatContext *s)
{
int i;
double start = 0.0;
WebMDashMuxContext *w = s->priv_data;
parse_adaptation_sets(s);
write_header(s);
avio_printf(s->pb, "<Period id=\"0\"");
avio_printf(s->pb, " start=\"PT%gS\"", start);
avio_printf(s->pb, " duration=\"PT%gS\"", get_duration(s));
avio_printf(s->pb, " >\n");
for (i = 0; i < w->nb_as; i++) {
if (write_adaptation_set(s, i) < 0) return -1;
}
avio_printf(s->pb, "</Period>\n");
write_footer(s);
return 0;
}
static int webm_dash_manifest_write_packet(AVFormatContext *s, AVPacket *pkt)
{
return AVERROR_EOF;
}
static int webm_dash_manifest_write_trailer(AVFormatContext *s)
{
WebMDashMuxContext *w = s->priv_data;
int i;
for (i = 0; i < w->nb_as; i++) {
av_freep(&w->as[i].streams);
}
av_freep(&w->as);
return 0;
}
#define OFFSET(x) offsetof(WebMDashMuxContext, x)
static const AVOption options[] = {
{ "adaptation_sets", "Adaptation sets. Syntax: id=0,streams=0,1,2 id=1,streams=3,4 and so on", OFFSET(adaptation_sets), AV_OPT_TYPE_STRING, { 0 }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
{ NULL },
};
#if CONFIG_WEBM_DASH_MANIFEST_MUXER
static const AVClass webm_dash_class = {
.class_name = "WebM DASH Manifest muxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_webm_dash_manifest_muxer = {
.name = "webm_dash_manifest",
.long_name = NULL_IF_CONFIG_SMALL("WebM DASH Manifest"),
.mime_type = "application/xml",
.extensions = "xml",
.priv_data_size = sizeof(WebMDashMuxContext),
.write_header = webm_dash_manifest_write_header,
.write_packet = webm_dash_manifest_write_packet,
.write_trailer = webm_dash_manifest_write_trailer,
.priv_class = &webm_dash_class,
};
#endif