FFmpeg
webm_chunk.c
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1 /*
2  * Copyright (c) 2015, Vignesh Venkatasubramanian
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file WebM Chunk Muxer
23  * The chunk muxer enables writing WebM Live chunks where there is a header
24  * chunk, followed by data chunks where each Cluster is written out as a Chunk.
25  */
26 
27 #include <float.h>
28 #include <time.h>
29 
30 #include "avformat.h"
31 #include "avio.h"
32 #include "avio_internal.h"
33 #include "internal.h"
34 
35 #include "libavutil/avassert.h"
36 #include "libavutil/log.h"
37 #include "libavutil/opt.h"
38 #include "libavutil/avstring.h"
39 #include "libavutil/parseutils.h"
40 #include "libavutil/mathematics.h"
41 #include "libavutil/time.h"
42 #include "libavutil/time_internal.h"
43 #include "libavutil/timestamp.h"
44 
45 #define MAX_FILENAME_SIZE 1024
46 
47 typedef struct WebMChunkContext {
48  const AVClass *class;
49  int chunk_start_index;
50  char *header_filename;
51  int chunk_duration;
52  int chunk_index;
53  char *http_method;
54  uint64_t duration_written;
55  int64_t prev_pts;
56  ff_const59 AVOutputFormat *oformat;
57  AVFormatContext *avf;
58 } WebMChunkContext;
59 
60 static int chunk_mux_init(AVFormatContext *s)
61 {
62  WebMChunkContext *wc = s->priv_data;
63  AVFormatContext *oc;
64  int ret;
65 
66  ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
67  if (ret < 0)
68  return ret;
69  oc = wc->avf;
70 
71  oc->interrupt_callback = s->interrupt_callback;
72  oc->max_delay = s->max_delay;
73  av_dict_copy(&oc->metadata, s->metadata, 0);
74 
75  *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
76  av_opt_set_defaults(oc->priv_data);
77  av_opt_set_int(oc->priv_data, "dash", 1, 0);
78  av_opt_set_int(oc->priv_data, "cluster_time_limit", wc->chunk_duration, 0);
79  av_opt_set_int(oc->priv_data, "live", 1, 0);
80 
81  oc->streams = s->streams;
82  oc->nb_streams = s->nb_streams;
83 
84  return 0;
85 }
86 
87 static int get_chunk_filename(AVFormatContext *s, int is_header, char filename[MAX_FILENAME_SIZE])
88 {
89  WebMChunkContext *wc = s->priv_data;
90  AVFormatContext *oc = wc->avf;
91  if (!filename) {
92  return AVERROR(EINVAL);
93  }
94  if (is_header) {
95  int len;
96  if (!wc->header_filename) {
97  av_log(oc, AV_LOG_ERROR, "No header filename provided\n");
98  return AVERROR(EINVAL);
99  }
100  len = av_strlcpy(filename, wc->header_filename, MAX_FILENAME_SIZE);
101  if (len >= MAX_FILENAME_SIZE) {
102  av_log(oc, AV_LOG_ERROR, "Header filename too long\n");
103  return AVERROR(EINVAL);
104  }
105  } else {
106  if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
107  s->url, wc->chunk_index - 1) < 0) {
108  av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
109  return AVERROR(EINVAL);
110  }
111  }
112  return 0;
113 }
114 
115 static int webm_chunk_write_header(AVFormatContext *s)
116 {
117  WebMChunkContext *wc = s->priv_data;
118  AVFormatContext *oc = NULL;
119  int ret;
120  int i;
121  AVDictionary *options = NULL;
122  char oc_filename[MAX_FILENAME_SIZE];
123  char *oc_url;
124 
125  // DASH Streams can only have either one track per file.
126  if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
127 
128  wc->chunk_index = wc->chunk_start_index;
129  wc->oformat = av_guess_format("webm", s->url, "video/webm");
130  if (!wc->oformat)
131  return AVERROR_MUXER_NOT_FOUND;
132  wc->prev_pts = AV_NOPTS_VALUE;
133 
134  ret = chunk_mux_init(s);
135  if (ret < 0)
136  return ret;
137  oc = wc->avf;
138  ret = get_chunk_filename(s, 1, oc_filename);
139  if (ret < 0)
140  return ret;
141  oc_url = av_strdup(oc_filename);
142  if (!oc_url)
143  return AVERROR(ENOMEM);
144  ff_format_set_url(oc, oc_url);
145  if (wc->http_method)
146  av_dict_set(&options, "method", wc->http_method, 0);
147  ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &options);
148  av_dict_free(&options);
149  if (ret < 0)
150  return ret;
151 
152  oc->pb->seekable = 0;
153  ret = oc->oformat->write_header(oc);
154  ff_format_io_close(s, &oc->pb);
155  if (ret < 0)
156  return ret;
157  for (i = 0; i < s->nb_streams; i++) {
158  // ms precision is the de-facto standard timescale for mkv files.
159  avpriv_set_pts_info(s->streams[i], 64, 1, 1000);
160  }
161  return 0;
162 }
163 
164 static int chunk_start(AVFormatContext *s)
165 {
166  WebMChunkContext *wc = s->priv_data;
167  AVFormatContext *oc = wc->avf;
168  int ret;
169 
170  ret = avio_open_dyn_buf(&oc->pb);
171  if (ret < 0)
172  return ret;
173  wc->chunk_index++;
174  return 0;
175 }
176 
177 static int chunk_end(AVFormatContext *s, int flush)
178 {
179  WebMChunkContext *wc = s->priv_data;
180  AVFormatContext *oc = wc->avf;
181  int ret;
182  int buffer_size;
183  uint8_t *buffer;
184  AVIOContext *pb;
185  char filename[MAX_FILENAME_SIZE];
186  AVDictionary *options = NULL;
187 
188  if (!oc->pb)
189  return 0;
190 
191  if (flush)
192  // Flush the cluster in WebM muxer.
193  oc->oformat->write_packet(oc, NULL);
194  buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
195  oc->pb = NULL;
196  ret = get_chunk_filename(s, 0, filename);
197  if (ret < 0)
198  goto fail;
199  if (wc->http_method)
200  av_dict_set(&options, "method", wc->http_method, 0);
201  ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
202  if (ret < 0)
203  goto fail;
204  avio_write(pb, buffer, buffer_size);
205  ff_format_io_close(s, &pb);
206 fail:
207  av_dict_free(&options);
208  av_free(buffer);
209  return (ret < 0) ? ret : 0;
210 }
211 
212 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
213 {
214  WebMChunkContext *wc = s->priv_data;
215  AVFormatContext *oc = wc->avf;
216  AVStream *st = s->streams[pkt->stream_index];
217  int ret;
218 
219  if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
220  if (wc->prev_pts != AV_NOPTS_VALUE)
221  wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
222  st->time_base,
223  (AVRational) {1, 1000});
224  wc->prev_pts = pkt->pts;
225  }
226 
227  // For video, a new chunk is started only on key frames. For audio, a new
228  // chunk is started based on chunk_duration. Also, a new chunk is started
229  // unconditionally if there is no currently open chunk.
230  if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
231  (pkt->flags & AV_PKT_FLAG_KEY)) ||
232  (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
233  wc->duration_written >= wc->chunk_duration)) {
234  wc->duration_written = 0;
235  if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
236  return ret;
237  }
238  }
239 
240  ret = oc->oformat->write_packet(oc, pkt);
241 
242  return ret;
243 }
244 
245 static int webm_chunk_write_trailer(AVFormatContext *s)
246 {
247  WebMChunkContext *wc = s->priv_data;
248  AVFormatContext *oc = wc->avf;
249  int ret;
250 
251  if (!oc->pb) {
252  ret = chunk_start(s);
253  if (ret < 0)
254  goto fail;
255  }
256  oc->oformat->write_trailer(oc);
257  ret = chunk_end(s, 0);
258 fail:
259  oc->streams = NULL;
260  oc->nb_streams = 0;
261  avformat_free_context(oc);
262  return ret;
263 }
264 
265 #define OFFSET(x) offsetof(WebMChunkContext, x)
266 static const AVOption options[] = {
267  { "chunk_start_index", "start index of the chunk", OFFSET(chunk_start_index), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
268  { "header", "filename of the header where the initialization data will be written", OFFSET(header_filename), AV_OPT_TYPE_STRING, { 0 }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
269  { "audio_chunk_duration", "duration of each chunk in milliseconds", OFFSET(chunk_duration), AV_OPT_TYPE_INT, {.i64 = 5000}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
270  { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
271  { NULL },
272 };
273 
274 #if CONFIG_WEBM_CHUNK_MUXER
275 static const AVClass webm_chunk_class = {
276  .class_name = "WebM Chunk Muxer",
277  .item_name = av_default_item_name,
278  .option = options,
279  .version = LIBAVUTIL_VERSION_INT,
280 };
281 
282 AVOutputFormat ff_webm_chunk_muxer = {
283  .name = "webm_chunk",
284  .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
285  .mime_type = "video/webm",
286  .extensions = "chk",
287  .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
288  AVFMT_TS_NONSTRICT,
289  .priv_data_size = sizeof(WebMChunkContext),
290  .write_header = webm_chunk_write_header,
291  .write_packet = webm_chunk_write_packet,
292  .write_trailer = webm_chunk_write_trailer,
293  .priv_class = &webm_chunk_class,
294 };
295 #endif
chunk_mux_init
static int chunk_mux_init(AVFormatContext *s)
Definition: webm_chunk.c:60
chunk_start
static int chunk_start(AVFormatContext *s)
Definition: webm_chunk.c:164
AVOutputFormat::name
const char * name
Definition: avformat.h:496
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
av_opt_set_defaults
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1305
webm_chunk_write_header
static int webm_chunk_write_header(AVFormatContext *s)
Definition: webm_chunk.c:115
WebMChunkContext::chunk_index
int chunk_index
Definition: webm_chunk.c:52
WebMChunkContext::prev_pts
int64_t prev_pts
Definition: webm_chunk.c:55
WebMChunkContext::http_method
char * http_method
Definition: webm_chunk.c:53
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1410
AVOption
AVOption.
Definition: opt.h:246
float.h
AVOutputFormat::write_packet
int(* write_packet)(struct AVFormatContext *, AVPacket *pkt)
Write a packet.
Definition: avformat.h:556
mathematics.h
AVDictionary
Definition: dict.c:30
AVOutputFormat::write_trailer
int(* write_trailer)(struct AVFormatContext *)
Definition: avformat.h:557
av_get_frame_filename
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Definition: utils.c:4751
WebMChunkContext
Definition: webm_chunk.c:47
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1509
ff_const59
#define ff_const59
The ff_const59 define is not part of the public API and will be removed without further warning.
Definition: avformat.h:540
av_guess_format
ff_const59 AVOutputFormat * av_guess_format(const char *short_name, const char *filename, const char *mime_type)
Return the output format in the list of registered output formats which best matches the provided par...
Definition: format.c:51
AVFormatContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1620
webm_chunk_write_trailer
static int webm_chunk_write_trailer(AVFormatContext *s)
Definition: webm_chunk.c:245
fail
#define fail()
Definition: checkasm.h:120
avio_close_dyn_buf
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1415
chunk_end
static int chunk_end(AVFormatContext *s, int flush)
Definition: webm_chunk.c:177
avassert.h
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVFormatContext::metadata
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1582
WebMChunkContext::header_filename
char * header_filename
Definition: webm_chunk.c:50
avio_open_dyn_buf
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1386
s
#define s(width, name)
Definition: cbs_vp9.c:257
AV_OPT_FLAG_ENCODING_PARAM
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:276
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:655
av_rescale_q
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:142
webm_chunk_write_packet
static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: webm_chunk.c:212
AVFMT_NEEDNUMBER
#define AVFMT_NEEDNUMBER
Needs 'd' in filename.
Definition: avformat.h:464
time_internal.h
AVOutputFormat::write_header
int(* write_header)(struct AVFormatContext *)
Definition: avformat.h:548
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1017
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
ff_webm_chunk_muxer
AVOutputFormat ff_webm_chunk_muxer
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
AVStream::time_base
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented.
Definition: avformat.h:899
flush
static void flush(AVCodecContext *avctx)
Definition: aacdec_template.c:500
NULL
#define NULL
Definition: coverity.c:32
write_trailer
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:94
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1384
parseutils.h
WebMChunkContext::oformat
ff_const59 AVOutputFormat * oformat
Definition: webm_chunk.c:56
time.h
AVOutputFormat::priv_class
const AVClass * priv_class
AVClass for the private context.
Definition: avformat.h:524
AVFormatContext::oformat
ff_const59 struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1361
av_opt_set_int
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:568
AVFormatContext::nb_streams
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1398
options
static const AVOption options[]
Definition: webm_chunk.c:266
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:188
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4910
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1438
avio.h
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:463
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:218
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1483
av_dict_free
void av_dict_free(AVDictionary **pm)
Free all the memory allocated for an AVDictionary struct and all keys and values.
Definition: dict.c:203
avformat_alloc_output_context2
int avformat_alloc_output_context2(AVFormatContext **ctx, ff_const59 AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:148
write_packet
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:690
log.h
AVFMT_GLOBALHEADER
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:466
AVOutputFormat
Definition: avformat.h:495
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
avio_internal.h
AVERROR_MUXER_NOT_FOUND
#define AVERROR_MUXER_NOT_FOUND
Muxer not found.
Definition: error.h:60
uint8_t
uint8_t
Definition: audio_convert.c:194
AVFormatContext::max_delay
int max_delay
Definition: avformat.h:1467
len
int len
Definition: vorbis_enc_data.h:452
AVFMT_TS_NONSTRICT
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:477
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:870
get_chunk_filename
static int get_chunk_filename(AVFormatContext *s, int is_header, char filename[MAX_FILENAME_SIZE])
Definition: webm_chunk.c:87
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
avformat.h
ff_format_set_url
void ff_format_set_url(AVFormatContext *s, char *url)
Set AVFormatContext url field to the provided pointer.
Definition: utils.c:5825
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:223
avformat_free_context
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4414
AVPacket::stream_index
int stream_index
Definition: avcodec.h:1479
ff_format_io_close
void ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
Definition: utils.c:5665
av_strdup
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
MAX_FILENAME_SIZE
#define MAX_FILENAME_SIZE
Definition: webm_chunk.c:45
av_free
#define av_free(p)
Definition: tableprint_vlc.h:34
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1454
av_dict_set
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:70
av_dict_copy
int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
Definition: dict.c:217
timestamp.h
av_strlcpy
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:83
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
OFFSET
#define OFFSET(x)
Definition: webm_chunk.c:265
WebMChunkContext::chunk_start_index
int chunk_start_index
Definition: webm_chunk.c:49
WebMChunkContext::avf
AVFormatContext * avf
Definition: webm_chunk.c:57
avstring.h
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:227
write_header
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:337
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1370
WebMChunkContext::duration_written
uint64_t duration_written
Definition: webm_chunk.c:54
WebMChunkContext::chunk_duration
int chunk_duration
Definition: webm_chunk.c:51
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