FFmpeg  4.2.1
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"
43 #include "libavutil/timestamp.h"
44 
45 #define MAX_FILENAME_SIZE 1024
46 
47 typedef struct WebMChunkContext {
48  const AVClass *class;
53  char *http_method;
54  uint64_t duration_written;
55  int64_t prev_pts;
59 
61 {
62  WebMChunkContext *wc = s->priv_data;
63  AVFormatContext *oc;
64  int ret;
65 
67  if (ret < 0)
68  return ret;
69  oc = wc->avf;
70 
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;
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 
116 {
117  WebMChunkContext *wc = s->priv_data;
118  AVFormatContext *oc = NULL;
119  int ret;
120  int i;
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)
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  if (ret < 0)
155  return ret;
156  ff_format_io_close(s, &oc->pb);
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 
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  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 
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)) ||
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 
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;
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 
283  .name = "webm_chunk",
284  .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
285  .mime_type = "video/webm",
286  .extensions = "chk",
289  .priv_data_size = sizeof(WebMChunkContext),
293  .priv_class = &webm_chunk_class,
294 };
295 #endif
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:689
int(* io_open)(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags, AVDictionary **options)
A callback for opening new IO streams.
Definition: avformat.h:1940
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
Buffered I/O operations.
AVIOInterruptCB interrupt_callback
Custom interrupt callbacks for the I/O layer.
Definition: avformat.h:1636
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1413
AVOption.
Definition: opt.h:246
static void flush(AVCodecContext *avctx)
static int chunk_start(AVFormatContext *s)
Definition: webm_chunk.c:164
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
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:4886
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1305
AVFormatContext * avf
Definition: webm_chunk.c:57
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
uint64_t duration_written
Definition: webm_chunk.c:54
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:655
int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
Definition: dict.c:217
static AVPacket pkt
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1384
char * http_method
Definition: webm_chunk.c:53
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:477
Format I/O context.
Definition: avformat.h:1358
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
static char buffer[20]
Definition: seek.c:32
uint8_t
AVOptions.
timestamp utils, mostly useful for debugging/logging purposes
void ff_format_io_close(AVFormatContext *s, AVIOContext **pb)
Definition: utils.c:5641
#define MAX_FILENAME_SIZE
Definition: webm_chunk.c:45
char * header_filename
Definition: webm_chunk.c:50
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:218
#define av_log(a,...)
#define AV_OPT_FLAG_ENCODING_PARAM
a generic parameter which can be set by the user for muxing or encoding
Definition: opt.h:276
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1509
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
#define ff_const59
The ff_const59 define is not part of the public API and will be removed without further warning...
Definition: avformat.h:549
static int get_chunk_filename(AVFormatContext *s, int is_header, char filename[MAX_FILENAME_SIZE])
Definition: webm_chunk.c:87
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVDictionary * metadata
Metadata that applies to the whole file.
Definition: avformat.h:1598
#define AVERROR(e)
Definition: error.h:43
static const AVOption options[]
Definition: webm_chunk.c:266
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
char * url
input or output URL.
Definition: avformat.h:1454
void av_dict_free(AVDictionary **pm)
Free all the memory allocated for an AVDictionary struct and all keys and values. ...
Definition: dict.c:203
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:568
static int chunk_mux_init(AVFormatContext *s)
Definition: webm_chunk.c:60
simple assert() macros that are a bit more flexible than ISO C assert().
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
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
#define fail()
Definition: checkasm.h:120
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1483
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1414
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
int(* write_header)(struct AVFormatContext *)
Definition: avformat.h:557
ff_const59 AVOutputFormat * oformat
Definition: webm_chunk.c:56
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:94
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:466
const char * name
Definition: avformat.h:505
#define OFFSET(x)
Definition: webm_chunk.c:265
#define s(width, name)
Definition: cbs_vp9.c:257
static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: webm_chunk.c:212
void ff_format_set_url(AVFormatContext *s, char *url)
Set AVFormatContext url field to the provided pointer.
Definition: utils.c:5801
const AVClass * priv_class
AVClass for the private context.
Definition: avformat.h:533
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Definition: utils.c:4727
ff_const59 struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1377
Stream structure.
Definition: avformat.h:881
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
static int webm_chunk_write_header(AVFormatContext *s)
Definition: webm_chunk.c:115
int(* write_trailer)(struct AVFormatContext *)
Definition: avformat.h:566
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
Describe the class of an AVClass context structure.
Definition: log.h:67
AVOutputFormat ff_webm_chunk_muxer
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
Rational number (pair of numerator and denominator).
Definition: rational.h:58
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:4393
misc parsing utilities
Main libavformat public API header.
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:463
static int webm_chunk_write_trailer(AVFormatContext *s)
Definition: webm_chunk.c:245
#define av_free(p)
int len
void * priv_data
Format private data.
Definition: avformat.h:1386
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:337
int(* write_packet)(struct AVFormatContext *, AVPacket *pkt)
Write a packet.
Definition: avformat.h:565
static int chunk_end(AVFormatContext *s, int flush)
Definition: webm_chunk.c:177
int64_t prev_pts
Definition: webm_chunk.c:55
#define AVERROR_MUXER_NOT_FOUND
Muxer not found.
Definition: error.h:60
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
int stream_index
Definition: avcodec.h:1479
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:910
This structure stores compressed data.
Definition: avcodec.h:1454
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
#define AVFMT_NEEDNUMBER
Needs &#39;d&#39; in filename.
Definition: avformat.h:464