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  st = ff_stream_clone(oc, ost);
95  if (!st)
96  return AVERROR(ENOMEM);
97 
98  if (wc->http_method)
99  if ((ret = av_dict_set(&dict, "method", wc->http_method, 0)) < 0)
100  return ret;
101  ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &dict);
102  av_dict_free(&dict);
103  if (ret < 0)
104  return ret;
105  oc->pb->seekable = 0;
106 
107  if ((ret = av_dict_set_int(&dict, "dash", 1, 0)) < 0 ||
108  (ret = av_dict_set_int(&dict, "cluster_time_limit",
109  wc->chunk_duration, 0)) < 0 ||
110  (ret = av_dict_set_int(&dict, "live", 1, 0)) < 0)
111  goto fail;
112 
113  ret = avformat_init_output(oc, &dict);
114 fail:
115  av_dict_free(&dict);
116  if (ret < 0)
117  return ret;
118 
119  // Copy the timing info back to the original stream
120  // so that the timestamps of the packets are directly usable
122  st->time_base.den);
123 
124  // This ensures that the timestamps will already be properly shifted
125  // when the packets arrive here, so we don't need to shift again.
126  s->avoid_negative_ts = oc->avoid_negative_ts;
130  ffformatcontext(oc)->avoid_negative_ts_status = AVOID_NEGATIVE_TS_DISABLED;
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  AVStream *st = s->streams[0], *ost = oc->streams[0];
154  int ret;
155 
157  ff_format_io_close(s, &oc->pb);
160  wc->header_written = 1;
161  if (ret < 0)
162  return ret;
163  return 0;
164 }
165 
167 {
168  WebMChunkContext *wc = s->priv_data;
169  AVFormatContext *oc = wc->avf;
170  int ret;
171 
172  ret = avio_open_dyn_buf(&oc->pb);
173  if (ret < 0)
174  return ret;
175  wc->chunk_index++;
176  return 0;
177 }
178 
179 static int chunk_end(AVFormatContext *s, int flush)
180 {
181  WebMChunkContext *wc = s->priv_data;
182  AVFormatContext *oc = wc->avf;
183  int ret;
184  int buffer_size;
185  uint8_t *buffer;
186  AVIOContext *pb;
187  char filename[MAX_FILENAME_SIZE];
189 
190  if (!oc->pb)
191  return 0;
192 
193  if (flush)
194  // Flush the cluster in WebM muxer.
195  av_write_frame(oc, NULL);
196  buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
197  oc->pb = NULL;
198  ret = get_chunk_filename(s, filename);
199  if (ret < 0)
200  goto fail;
201  if (wc->http_method)
202  if ((ret = av_dict_set(&options, "method", wc->http_method, 0)) < 0)
203  goto fail;
204  ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
206  if (ret < 0)
207  goto fail;
208  avio_write(pb, buffer, buffer_size);
209  ff_format_io_close(s, &pb);
210 fail:
211  av_free(buffer);
212  return (ret < 0) ? ret : 0;
213 }
214 
216 {
217  WebMChunkContext *wc = s->priv_data;
218  AVFormatContext *oc = wc->avf;
219  AVStream *st = s->streams[pkt->stream_index];
220  int ret;
221 
222  if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
223  if (wc->prev_pts != AV_NOPTS_VALUE)
225  st->time_base,
226  (AVRational) {1, 1000});
227  wc->prev_pts = pkt->pts;
228  }
229 
230  // For video, a new chunk is started only on key frames. For audio, a new
231  // chunk is started based on chunk_duration. Also, a new chunk is started
232  // unconditionally if there is no currently open chunk.
233  if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
234  (pkt->flags & AV_PKT_FLAG_KEY)) ||
236  wc->duration_written >= wc->chunk_duration)) {
237  wc->duration_written = 0;
238  if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
239  return ret;
240  }
241  }
242 
243  // We only have one stream, so use the non-interleaving av_write_frame.
244  return av_write_frame(oc, pkt);
245 }
246 
248 {
249  WebMChunkContext *wc = s->priv_data;
250  AVFormatContext *oc = wc->avf;
251  int ret;
252 
253  if (!oc->pb) {
254  ret = chunk_start(s);
255  if (ret < 0)
256  return ret;
257  }
258  ret = av_write_trailer(oc);
259  if (ret < 0)
260  return ret;
261  return chunk_end(s, 0);
262 }
263 
265 {
266  WebMChunkContext *wc = s->priv_data;
267 
268  if (!wc->avf)
269  return;
270 
271  if (wc->header_written)
272  ffio_free_dyn_buf(&wc->avf->pb);
273  else
274  ff_format_io_close(s, &wc->avf->pb);
276  wc->avf = NULL;
277 }
278 
279 #define OFFSET(x) offsetof(WebMChunkContext, x)
280 static const AVOption options[] = {
281  { "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 },
282  { "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 },
283  { "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 },
284  { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
285  { NULL },
286 };
287 
288 static const AVClass webm_chunk_class = {
289  .class_name = "WebM Chunk Muxer",
290  .item_name = av_default_item_name,
291  .option = options,
292  .version = LIBAVUTIL_VERSION_INT,
293 };
294 
296  .name = "webm_chunk",
297  .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
298  .mime_type = "video/webm",
299  .extensions = "chk",
302  .priv_data_size = sizeof(WebMChunkContext),
308  .priv_class = &webm_chunk_class,
309 };
webm_chunk_class
static const AVClass webm_chunk_class
Definition: webm_chunk.c:288
chunk_start
static int chunk_start(AVFormatContext *s)
Definition: webm_chunk.c:166
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:58
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:43
ffformatcontext
static av_always_inline FFFormatContext * ffformatcontext(AVFormatContext *s)
Definition: internal.h:191
WebMChunkContext::prev_pts
int64_t prev_pts
Definition: webm_chunk.c:46
WebMChunkContext::http_method
char * http_method
Definition: webm_chunk.c:44
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1284
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:1513
AVOption
AVOption.
Definition: opt.h:251
mathematics.h
AVDictionary
Definition: dict.c:32
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:429
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:135
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:429
AVFormatContext::interrupt_callback
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1483
webm_chunk_write_trailer
static int webm_chunk_write_trailer(AVFormatContext *s)
Definition: webm_chunk.c:247
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:763
AVFormatContext::flush_packets
int flush_packets
Flush the I/O context after each packet.
Definition: avformat.h:1633
ffstream
static av_always_inline FFStream * ffstream(AVStream *st)
Definition: internal.h:413
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:1530
chunk_end
static int chunk_end(AVFormatContext *s, int flush)
Definition: webm_chunk.c:179
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:1445
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:1485
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:1334
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:363
AVIO_FLAG_WRITE
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:634
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:215
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:450
AVFMT_NEEDNUMBER
#define AVFMT_NEEDNUMBER
Needs 'd' in filename.
Definition: avformat.h:471
FFFormatContext::avoid_negative_ts_status
enum FFFormatContext::@281 avoid_negative_ts_status
Whether the timestamp shift offset has already been determined.
AVFormatContext
Format I/O context.
Definition: avformat.h:1216
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:1550
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
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:1258
av_write_frame
int av_write_frame(AVFormatContext *s, AVPacket *pkt)
Write a packet to an output media file.
Definition: mux.c:1192
webm_chunk_init
static int webm_chunk_init(AVFormatContext *s)
Definition: webm_chunk.c:51
options
static const AVOption options[]
Definition: webm_chunk.c:280
AVIOContext
Bytestream IO Context.
Definition: avio.h:166
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:115
AVIOContext::seekable
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:267
AVFormatContext::url
char * url
input or output URL.
Definition: avformat.h:1299
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:845
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:223
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:1254
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:1548
AVFormatContext::max_delay
int max_delay
Definition: avformat.h:1328
write_packet
static int write_packet(Muxer *mux, OutputStream *ost, AVPacket *pkt)
Definition: ffmpeg_mux.c:61
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:1558
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:167
webm_chunk_deinit
static void webm_chunk_deinit(AVFormatContext *s)
Definition: webm_chunk.c:264
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
flush
void(* flush)(AVBSFContext *ctx)
Definition: dts2pts_bsf.c:365
MAX_FILENAME_SIZE
#define MAX_FILENAME_SIZE
Definition: webm_chunk.c:37
av_free
#define av_free(p)
Definition: tableprint_vlc.h:33
ff_stream_clone
AVStream * ff_stream_clone(AVFormatContext *dst_ctx, const AVStream *src)
Create a new stream and copy to it all parameters from a source stream, with the exception of the ind...
Definition: avformat.c:286
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:86
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:237
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:295
AVFMT_FLAG_FLUSH_PACKETS
#define AVFMT_FLAG_FLUSH_PACKETS
Flush the AVIOContext every packet.
Definition: avformat.h:1344
OFFSET
#define OFFSET(x)
Definition: webm_chunk.c:279
WebMChunkContext::avf
AVFormatContext * avf
Definition: webm_chunk.c:47
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: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:838
FFStream::lowest_ts_allowed
int64_t lowest_ts_allowed
This is the lowest ts allowed in this track; it may be set by the muxer during init or write_header a...
Definition: internal.h:317
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:153