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 "avformat.h"
28 #include "avio.h"
29 #include "avio_internal.h"
30 #include "internal.h"
31 
32 #include "libavutil/log.h"
33 #include "libavutil/opt.h"
34 #include "libavutil/mathematics.h"
35 
36 #define MAX_FILENAME_SIZE 1024
37 
38 typedef struct WebMChunkContext {
39  const AVClass *class;
43  char *http_method;
44  uint64_t duration_written;
45  int64_t prev_pts;
49 
51 {
52  WebMChunkContext *wc = s->priv_data;
53  const AVOutputFormat *oformat;
54  AVFormatContext *oc;
55  AVStream *st, *ost = s->streams[0];
56  AVDictionary *dict = NULL;
57  int ret;
58 
59  // DASH Streams can only have one track per file.
60  if (s->nb_streams != 1)
61  return AVERROR(EINVAL);
62 
63  if (!wc->header_filename) {
64  av_log(s, AV_LOG_ERROR, "No header filename provided\n");
65  return AVERROR(EINVAL);
66  }
67 
69 
70  oformat = av_guess_format("webm", s->url, "video/webm");
71  if (!oformat)
73 
74  ret = avformat_alloc_output_context2(&wc->avf, oformat, NULL, NULL);
75  if (ret < 0)
76  return ret;
77  oc = wc->avf;
78 
80  wc->header_filename = NULL;
81 
82  oc->interrupt_callback = s->interrupt_callback;
83  oc->max_delay = s->max_delay;
84  oc->flags = s->flags & ~AVFMT_FLAG_FLUSH_PACKETS;
85  oc->strict_std_compliance = s->strict_std_compliance;
86  oc->avoid_negative_ts = s->avoid_negative_ts;
87 
88  oc->flush_packets = 0;
89 
90  if ((ret = av_dict_copy(&oc->metadata, s->metadata, 0)) < 0)
91  return ret;
92 
93  if (!(st = avformat_new_stream(oc, NULL)))
94  return AVERROR(ENOMEM);
95 
96  if ((ret = ff_stream_encode_params_copy(st, ost)) < 0)
97  return ret;
98 
99  if (wc->http_method)
100  if ((ret = av_dict_set(&dict, "method", wc->http_method, 0)) < 0)
101  return ret;
102  ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &dict);
103  av_dict_free(&dict);
104  if (ret < 0)
105  return ret;
106  oc->pb->seekable = 0;
107 
108  if ((ret = av_dict_set_int(&dict, "dash", 1, 0)) < 0 ||
109  (ret = av_dict_set_int(&dict, "cluster_time_limit",
110  wc->chunk_duration, 0)) < 0 ||
111  (ret = av_dict_set_int(&dict, "live", 1, 0)) < 0)
112  goto fail;
113 
114  ret = avformat_init_output(oc, &dict);
115 fail:
116  av_dict_free(&dict);
117  if (ret < 0)
118  return ret;
119 
120  // Copy the timing info back to the original stream
121  // so that the timestamps of the packets are directly usable
123  st->time_base.den);
124 
125  // This ensures that the timestamps will already be properly shifted
126  // when the packets arrive here, so we don't need to shift again.
127  s->avoid_negative_ts = oc->avoid_negative_ts;
128  s->internal->avoid_negative_ts_use_pts =
130  oc->avoid_negative_ts = 0;
131 
132  return 0;
133 }
134 
136 {
137  WebMChunkContext *wc = s->priv_data;
138  if (!filename) {
139  return AVERROR(EINVAL);
140  }
142  s->url, wc->chunk_index - 1) < 0) {
143  av_log(s, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
144  return AVERROR(EINVAL);
145  }
146  return 0;
147 }
148 
150 {
151  WebMChunkContext *wc = s->priv_data;
152  AVFormatContext *oc = wc->avf;
153  int ret;
154 
156  ff_format_io_close(s, &oc->pb);
157  wc->header_written = 1;
158  if (ret < 0)
159  return ret;
160  return 0;
161 }
162 
164 {
165  WebMChunkContext *wc = s->priv_data;
166  AVFormatContext *oc = wc->avf;
167  int ret;
168 
169  ret = avio_open_dyn_buf(&oc->pb);
170  if (ret < 0)
171  return ret;
172  wc->chunk_index++;
173  return 0;
174 }
175 
176 static int chunk_end(AVFormatContext *s, int flush)
177 {
178  WebMChunkContext *wc = s->priv_data;
179  AVFormatContext *oc = wc->avf;
180  int ret;
181  int buffer_size;
182  uint8_t *buffer;
183  AVIOContext *pb;
184  char filename[MAX_FILENAME_SIZE];
186 
187  if (!oc->pb)
188  return 0;
189 
190  if (flush)
191  // Flush the cluster in WebM muxer.
192  av_write_frame(oc, NULL);
193  buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
194  oc->pb = NULL;
195  ret = get_chunk_filename(s, filename);
196  if (ret < 0)
197  goto fail;
198  if (wc->http_method)
199  if ((ret = av_dict_set(&options, "method", wc->http_method, 0)) < 0)
200  goto fail;
201  ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
203  if (ret < 0)
204  goto fail;
205  avio_write(pb, buffer, buffer_size);
206  ff_format_io_close(s, &pb);
207 fail:
208  av_free(buffer);
209  return (ret < 0) ? ret : 0;
210 }
211 
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)
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)) ||
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  // We only have one stream, so use the non-interleaving av_write_frame.
241  return av_write_frame(oc, pkt);
242 }
243 
245 {
246  WebMChunkContext *wc = s->priv_data;
247  AVFormatContext *oc = wc->avf;
248  int ret;
249 
250  if (!oc->pb) {
251  ret = chunk_start(s);
252  if (ret < 0)
253  return ret;
254  }
255  ret = av_write_trailer(oc);
256  if (ret < 0)
257  return ret;
258  return chunk_end(s, 0);
259 }
260 
262 {
263  WebMChunkContext *wc = s->priv_data;
264 
265  if (!wc->avf)
266  return;
267 
268  if (wc->header_written)
269  ffio_free_dyn_buf(&wc->avf->pb);
270  else
271  ff_format_io_close(s, &wc->avf->pb);
273  wc->avf = NULL;
274 }
275 
276 #define OFFSET(x) offsetof(WebMChunkContext, x)
277 static const AVOption options[] = {
278  { "chunk_start_index", "start index of the chunk", OFFSET(chunk_index), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
279  { "header", "filename of the header where the initialization data will be written", OFFSET(header_filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
280  { "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 },
281  { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
282  { NULL },
283 };
284 
285 static const AVClass webm_chunk_class = {
286  .class_name = "WebM Chunk Muxer",
287  .item_name = av_default_item_name,
288  .option = options,
289  .version = LIBAVUTIL_VERSION_INT,
290 };
291 
293  .name = "webm_chunk",
294  .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
295  .mime_type = "video/webm",
296  .extensions = "chk",
299  .priv_data_size = sizeof(WebMChunkContext),
304  .deinit = webm_chunk_deinit,
305  .priv_class = &webm_chunk_class,
306 };
webm_chunk_class
static const AVClass webm_chunk_class
Definition: webm_chunk.c:285
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
chunk_start
static int chunk_start(AVFormatContext *s)
Definition: webm_chunk.c:163
AVOutputFormat::name
const char * name
Definition: avformat.h:491
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4374
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
webm_chunk_write_header
static int webm_chunk_write_header(AVFormatContext *s)
Definition: webm_chunk.c:149
WebMChunkContext::chunk_index
int chunk_index
Definition: webm_chunk.c:42
WebMChunkContext::prev_pts
int64_t prev_pts
Definition: webm_chunk.c:45
AVFormatInternal::avoid_negative_ts_use_pts
int avoid_negative_ts_use_pts
Definition: internal.h:137
WebMChunkContext::http_method
char * http_method
Definition: webm_chunk.c:43
AVFormatContext::strict_std_compliance
int strict_std_compliance
Allow non-standard and experimental extension.
Definition: avformat.h:1397
AVOption
AVOption.
Definition: opt.h:248
mathematics.h
AVDictionary
Definition: dict.c:30
avformat_init_output
av_warn_unused_result int avformat_init_output(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and initialize the codec, but do not write the header.
Definition: mux.c:448
AVFormatContext::internal
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1554
av_get_frame_filename
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Definition: utils.c:4648
WebMChunkContext
Definition: webm_chunk.c:38
get_chunk_filename
static int get_chunk_filename(AVFormatContext *s, char filename[MAX_FILENAME_SIZE])
Definition: webm_chunk.c:135
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:396
AVFormatContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1367
webm_chunk_write_trailer
static int webm_chunk_write_trailer(AVFormatContext *s)
Definition: webm_chunk.c:244
AVFormatContext::flush_packets
int flush_packets
Flush the I/O context after each packet.
Definition: avformat.h:1516
fail
#define fail()
Definition: checkasm.h:134
AVRational::num
int num
Numerator.
Definition: rational.h:59
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:1407
chunk_end
static int chunk_end(AVFormatContext *s, int flush)
Definition: webm_chunk.c:176
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:181
AVFormatContext::metadata
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1329
WebMChunkContext::header_filename
char * header_filename
Definition: webm_chunk.c:40
avio_open_dyn_buf
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1362
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:278
AVFormatContext::flags
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1224
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:675
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
avformat_write_header
av_warn_unused_result int avformat_write_header(AVFormatContext *s, AVDictionary **options)
Allocate the stream private data and write the stream header to an output media file.
Definition: mux.c:468
AVFMT_NEEDNUMBER
#define AVFMT_NEEDNUMBER
Needs 'd' in filename.
Definition: avformat.h:459
AVFormatContext
Format I/O context.
Definition: avformat.h:1106
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:979
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
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:855
flush
static void flush(AVCodecContext *avctx)
Definition: aacdec_template.c:592
NULL
#define NULL
Definition: coverity.c:32
write_trailer
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:98
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:235
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1148
av_write_frame
int av_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file.
Definition: mux.c:1174
webm_chunk_init
static int webm_chunk_init(AVFormatContext *s)
Definition: webm_chunk.c:50
options
static const AVOption options[]
Definition: webm_chunk.c:277
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:117
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:4799
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1189
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:458
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:215
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:371
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
write_packet
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:729
av_write_trailer
int av_write_trailer(AVFormatContext *s)
Write the stream trailer to an output media file and free the file private data.
Definition: mux.c:1236
log.h
AVFMT_GLOBALHEADER
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:461
AVOutputFormat
Definition: avformat.h:490
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:358
avio_internal.h
AVERROR_MUXER_NOT_FOUND
#define AVERROR_MUXER_NOT_FOUND
Muxer not found.
Definition: error.h:60
AVFormatContext::avoid_negative_ts
int avoid_negative_ts
Avoid negative timestamps during muxing.
Definition: avformat.h:1432
AVFormatContext::max_delay
int max_delay
Definition: avformat.h:1218
AVFMT_TS_NONSTRICT
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:472
ffio_free_dyn_buf
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1437
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:832
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
WebMChunkContext::header_written
int header_written
Definition: webm_chunk.c:47
ff_format_set_url
void ff_format_set_url(AVFormatContext *s, char *url)
Set AVFormatContext url field to the provided pointer.
Definition: utils.c:5606
ost
OutputStream * ost
Definition: ffmpeg_filter.c:163
ff_stream_encode_params_copy
int ff_stream_encode_params_copy(AVStream *dst, const AVStream *src)
Copy encoding parameters from source to destination stream.
Definition: utils.c:4204
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
AVRational::den
int den
Denominator.
Definition: rational.h:60
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:225
avformat_free_context
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4301
AVPacket::stream_index
int stream_index
Definition: packet.h:367
av_dict_set_int
int av_dict_set_int(AVDictionary **pm, const char *key, int64_t value, int flags)
Convenience wrapper for av_dict_set that converts the value to a string and stores it.
Definition: dict.c:147
ff_format_io_close
void ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
Definition: utils.c:5452
webm_chunk_deinit
static void webm_chunk_deinit(AVFormatContext *s)
Definition: webm_chunk.c:261
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
av_guess_format
const 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
MAX_FILENAME_SIZE
#define MAX_FILENAME_SIZE
Definition: webm_chunk.c:36
av_free
#define av_free(p)
Definition: tableprint_vlc.h:34
AVPacket
This structure stores compressed data.
Definition: packet.h:342
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
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
ff_webm_chunk_muxer
const AVOutputFormat ff_webm_chunk_muxer
Definition: webm_chunk.c:292
AVFMT_FLAG_FLUSH_PACKETS
#define AVFMT_FLAG_FLUSH_PACKETS
Flush the AVIOContext every packet.
Definition: avformat.h:1234
OFFSET
#define OFFSET(x)
Definition: webm_chunk.c:276
WebMChunkContext::avf
AVFormatContext * avf
Definition: webm_chunk.c:46
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:229
write_header
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:346
avformat_alloc_output_context2
int avformat_alloc_output_context2(AVFormatContext **ctx, const AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:136
AVStream::pts_wrap_bits
int pts_wrap_bits
number of bits in pts (used for wrapping control)
Definition: avformat.h:991
WebMChunkContext::duration_written
uint64_t duration_written
Definition: webm_chunk.c:44
WebMChunkContext::chunk_duration
int chunk_duration
Definition: webm_chunk.c:41