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 #include "mux.h"
32 
33 #include "libavutil/log.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/mathematics.h"
36 
37 #define MAX_FILENAME_SIZE 1024
38 
39 typedef struct WebMChunkContext {
40  const AVClass *class;
44  char *http_method;
45  uint64_t duration_written;
46  int64_t prev_pts;
50 
52 {
53  WebMChunkContext *wc = s->priv_data;
54  const AVOutputFormat *oformat;
55  AVFormatContext *oc;
56  AVStream *st, *ost = s->streams[0];
57  AVDictionary *dict = NULL;
58  int ret;
59 
60  // DASH Streams can only have one track per file.
61  if (s->nb_streams != 1)
62  return AVERROR(EINVAL);
63 
64  if (!wc->header_filename) {
65  av_log(s, AV_LOG_ERROR, "No header filename provided\n");
66  return AVERROR(EINVAL);
67  }
68 
70 
71  oformat = av_guess_format("webm", s->url, "video/webm");
72  if (!oformat)
74 
75  ret = avformat_alloc_output_context2(&wc->avf, oformat, NULL, NULL);
76  if (ret < 0)
77  return ret;
78  oc = wc->avf;
79 
81  wc->header_filename = NULL;
82 
83  oc->interrupt_callback = s->interrupt_callback;
84  oc->max_delay = s->max_delay;
85  oc->flags = s->flags & ~AVFMT_FLAG_FLUSH_PACKETS;
86  oc->strict_std_compliance = s->strict_std_compliance;
87  oc->avoid_negative_ts = s->avoid_negative_ts;
88 
89  oc->flush_packets = 0;
90 
91  if ((ret = av_dict_copy(&oc->metadata, s->metadata, 0)) < 0)
92  return ret;
93 
94  if (!(st = avformat_new_stream(oc, NULL)))
95  return AVERROR(ENOMEM);
96 
97  if ((ret = ff_stream_encode_params_copy(st, ost)) < 0)
98  return ret;
99 
100  if (wc->http_method)
101  if ((ret = av_dict_set(&dict, "method", wc->http_method, 0)) < 0)
102  return ret;
103  ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &dict);
104  av_dict_free(&dict);
105  if (ret < 0)
106  return ret;
107  oc->pb->seekable = 0;
108 
109  if ((ret = av_dict_set_int(&dict, "dash", 1, 0)) < 0 ||
110  (ret = av_dict_set_int(&dict, "cluster_time_limit",
111  wc->chunk_duration, 0)) < 0 ||
112  (ret = av_dict_set_int(&dict, "live", 1, 0)) < 0)
113  goto fail;
114 
115  ret = avformat_init_output(oc, &dict);
116 fail:
117  av_dict_free(&dict);
118  if (ret < 0)
119  return ret;
120 
121  // Copy the timing info back to the original stream
122  // so that the timestamps of the packets are directly usable
124  st->time_base.den);
125 
126  // This ensures that the timestamps will already be properly shifted
127  // when the packets arrive here, so we don't need to shift again.
128  s->avoid_negative_ts = oc->avoid_negative_ts;
132 
133  return 0;
134 }
135 
137 {
138  WebMChunkContext *wc = s->priv_data;
139  if (!filename) {
140  return AVERROR(EINVAL);
141  }
143  s->url, wc->chunk_index - 1) < 0) {
144  av_log(s, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
145  return AVERROR(EINVAL);
146  }
147  return 0;
148 }
149 
151 {
152  WebMChunkContext *wc = s->priv_data;
153  AVFormatContext *oc = wc->avf;
154  int ret;
155 
157  ff_format_io_close(s, &oc->pb);
158  wc->header_written = 1;
159  if (ret < 0)
160  return ret;
161  return 0;
162 }
163 
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];
187 
188  if (!oc->pb)
189  return 0;
190 
191  if (flush)
192  // Flush the cluster in WebM muxer.
193  av_write_frame(oc, NULL);
194  buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
195  oc->pb = NULL;
196  ret = get_chunk_filename(s, filename);
197  if (ret < 0)
198  goto fail;
199  if (wc->http_method)
200  if ((ret = av_dict_set(&options, "method", wc->http_method, 0)) < 0)
201  goto fail;
202  ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
204  if (ret < 0)
205  goto fail;
206  avio_write(pb, buffer, buffer_size);
207  ff_format_io_close(s, &pb);
208 fail:
209  av_free(buffer);
210  return (ret < 0) ? ret : 0;
211 }
212 
214 {
215  WebMChunkContext *wc = s->priv_data;
216  AVFormatContext *oc = wc->avf;
217  AVStream *st = s->streams[pkt->stream_index];
218  int ret;
219 
220  if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
221  if (wc->prev_pts != AV_NOPTS_VALUE)
223  st->time_base,
224  (AVRational) {1, 1000});
225  wc->prev_pts = pkt->pts;
226  }
227 
228  // For video, a new chunk is started only on key frames. For audio, a new
229  // chunk is started based on chunk_duration. Also, a new chunk is started
230  // unconditionally if there is no currently open chunk.
231  if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
232  (pkt->flags & AV_PKT_FLAG_KEY)) ||
234  wc->duration_written >= wc->chunk_duration)) {
235  wc->duration_written = 0;
236  if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
237  return ret;
238  }
239  }
240 
241  // We only have one stream, so use the non-interleaving av_write_frame.
242  return av_write_frame(oc, pkt);
243 }
244 
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  return ret;
255  }
256  ret = av_write_trailer(oc);
257  if (ret < 0)
258  return ret;
259  return chunk_end(s, 0);
260 }
261 
263 {
264  WebMChunkContext *wc = s->priv_data;
265 
266  if (!wc->avf)
267  return;
268 
269  if (wc->header_written)
270  ffio_free_dyn_buf(&wc->avf->pb);
271  else
272  ff_format_io_close(s, &wc->avf->pb);
274  wc->avf = NULL;
275 }
276 
277 #define OFFSET(x) offsetof(WebMChunkContext, x)
278 static const AVOption options[] = {
279  { "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 },
280  { "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 },
281  { "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 },
282  { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
283  { NULL },
284 };
285 
286 static const AVClass webm_chunk_class = {
287  .class_name = "WebM Chunk Muxer",
288  .item_name = av_default_item_name,
289  .option = options,
290  .version = LIBAVUTIL_VERSION_INT,
291 };
292 
294  .name = "webm_chunk",
295  .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
296  .mime_type = "video/webm",
297  .extensions = "chk",
300  .priv_data_size = sizeof(WebMChunkContext),
306  .priv_class = &webm_chunk_class,
307 };
webm_chunk_class
static const AVClass webm_chunk_class
Definition: webm_chunk.c:286
chunk_start
static int chunk_start(AVFormatContext *s)
Definition: webm_chunk.c:164
AVOutputFormat::name
const char * name
Definition: avformat.h:510
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: options.c:237
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:57
webm_chunk_write_header
static int webm_chunk_write_header(AVFormatContext *s)
Definition: webm_chunk.c:150
WebMChunkContext::chunk_index
int chunk_index
Definition: webm_chunk.c:43
ffformatcontext
static av_always_inline FFFormatContext * ffformatcontext(AVFormatContext *s)
Definition: internal.h:192
WebMChunkContext::prev_pts
int64_t prev_pts
Definition: webm_chunk.c:46
WebMChunkContext::http_method
char * http_method
Definition: webm_chunk.c:44
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: mux_utils.c:124
deinit
static void deinit(AVFormatContext *s)
Definition: chromaprint.c:49
AVFormatContext::strict_std_compliance
int strict_std_compliance
Allow non-standard and experimental extension.
Definition: avformat.h:1510
AVOption
AVOption.
Definition: opt.h:251
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:428
av_get_frame_filename
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Definition: utils.c:352
WebMChunkContext
Definition: webm_chunk.c:39
ost
static AVStream * ost
Definition: vaapi_transcode.c:45
get_chunk_filename
static int get_chunk_filename(AVFormatContext *s, char filename[MAX_FILENAME_SIZE])
Definition: webm_chunk.c:136
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:429
init
static int init
Definition: av_tx.c:47
AVFormatContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1480
webm_chunk_write_trailer
static int webm_chunk_write_trailer(AVFormatContext *s)
Definition: webm_chunk.c:245
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:697
AVFormatContext::flush_packets
int flush_packets
Flush the I/O context after each packet.
Definition: avformat.h:1630
fail
#define fail()
Definition: checkasm.h:130
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:1516
chunk_end
static int chunk_end(AVFormatContext *s, int flush)
Definition: webm_chunk.c:177
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:180
AVFormatContext::metadata
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1442
WebMChunkContext::header_filename
char * header_filename
Definition: webm_chunk.c:41
avio_open_dyn_buf
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1471
s
#define s(width, name)
Definition: cbs_vp9.c:256
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:281
AVFormatContext::flags
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1331
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:623
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:213
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:449
AVFMT_NEEDNUMBER
#define AVFMT_NEEDNUMBER
Needs 'd' in filename.
Definition: avformat.h:471
AVFormatContext
Format I/O context.
Definition: avformat.h:1213
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1108
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
AVFMT_AVOID_NEG_TS_DISABLED
#define AVFMT_AVOID_NEG_TS_DISABLED
Do not shift timestamps even when they are negative.
Definition: avformat.h:1547
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:978
flush
static void flush(AVCodecContext *avctx)
Definition: aacdec_template.c:606
NULL
#define NULL
Definition: coverity.c:32
write_trailer
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:100
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:237
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1255
av_write_frame
int av_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file.
Definition: mux.c:1188
webm_chunk_init
static int webm_chunk_init(AVFormatContext *s)
Definition: webm_chunk.c:51
options
static const AVOption options[]
Definition: webm_chunk.c:278
AVIOContext
Bytestream IO Context.
Definition: avio.h:162
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:116
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:263
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1296
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:470
ff_format_io_close
int ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
Definition: avformat.c:779
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:232
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:380
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
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:1250
log.h
AVFMT_GLOBALHEADER
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:480
AVOutputFormat
Definition: avformat.h:509
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:367
avio_internal.h
AVERROR_MUXER_NOT_FOUND
#define AVERROR_MUXER_NOT_FOUND
Muxer not found.
Definition: error.h:62
AVFormatContext::avoid_negative_ts
int avoid_negative_ts
Avoid negative timestamps during muxing.
Definition: avformat.h:1545
AVFormatContext::max_delay
int max_delay
Definition: avformat.h:1325
AVFMT_TS_NONSTRICT
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:491
ffio_free_dyn_buf
void ffio_free_dyn_buf(AVIOContext **s)
Free a dynamic buffer.
Definition: aviobuf.c:1544
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:948
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:71
avformat.h
WebMChunkContext::header_written
int header_written
Definition: webm_chunk.c:48
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: avformat.c:95
AVPacket::stream_index
int stream_index
Definition: packet.h:376
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
webm_chunk_deinit
static void webm_chunk_deinit(AVFormatContext *s)
Definition: webm_chunk.c:262
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:53
MAX_FILENAME_SIZE
#define MAX_FILENAME_SIZE
Definition: webm_chunk.c:37
av_free
#define av_free(p)
Definition: tableprint_vlc.h:33
AVPacket
This structure stores compressed data.
Definition: packet.h:351
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:27
ff_webm_chunk_muxer
const AVOutputFormat ff_webm_chunk_muxer
Definition: webm_chunk.c:293
AVFMT_FLAG_FLUSH_PACKETS
#define AVFMT_FLAG_FLUSH_PACKETS
Flush the AVIOContext every packet.
Definition: avformat.h:1341
OFFSET
#define OFFSET(x)
Definition: webm_chunk.c:277
WebMChunkContext::avf
AVFormatContext * avf
Definition: webm_chunk.c:47
write_packet
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:92
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:229
write_header
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:347
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:91
AVStream::pts_wrap_bits
int pts_wrap_bits
Number of bits in timestamps.
Definition: avformat.h:1117
ff_format_set_url
void ff_format_set_url(AVFormatContext *s, char *url)
Set AVFormatContext url field to the provided pointer.
Definition: avformat.c:772
WebMChunkContext::duration_written
uint64_t duration_written
Definition: webm_chunk.c:45
WebMChunkContext::chunk_duration
int chunk_duration
Definition: webm_chunk.c:42
mux.h
FFFormatContext::avoid_negative_ts_use_pts
int avoid_negative_ts_use_pts
Definition: internal.h:154