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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 "internal.h"
33 
34 #include "libavutil/avassert.h"
35 #include "libavutil/log.h"
36 #include "libavutil/opt.h"
37 #include "libavutil/avstring.h"
38 #include "libavutil/parseutils.h"
39 #include "libavutil/mathematics.h"
40 #include "libavutil/time.h"
42 #include "libavutil/timestamp.h"
43 
44 #define MAX_FILENAME_SIZE 1024
45 
46 typedef struct WebMChunkContext {
47  const AVClass *class;
52  uint64_t duration_written;
53  int prev_pts;
57 
59 {
60  WebMChunkContext *wc = s->priv_data;
61  AVFormatContext *oc;
62  int ret;
63 
65  if (ret < 0)
66  return ret;
67  oc = wc->avf;
68 
70  oc->max_delay = s->max_delay;
71  av_dict_copy(&oc->metadata, s->metadata, 0);
72 
73  *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
75  av_opt_set_int(oc->priv_data, "dash", 1, 0);
76  av_opt_set_int(oc->priv_data, "cluster_time_limit", wc->chunk_duration, 0);
77  av_opt_set_int(oc->priv_data, "live", 1, 0);
78 
79  oc->streams = s->streams;
80  oc->nb_streams = s->nb_streams;
81 
82  return 0;
83 }
84 
85 static int get_chunk_filename(AVFormatContext *s, int is_header, char *filename)
86 {
87  WebMChunkContext *wc = s->priv_data;
88  AVFormatContext *oc = wc->avf;
89  if (!filename) {
90  return AVERROR(EINVAL);
91  }
92  if (is_header) {
93  if (!wc->header_filename) {
94  return AVERROR(EINVAL);
95  }
96  av_strlcpy(filename, wc->header_filename, strlen(wc->header_filename) + 1);
97  } else {
99  s->filename, wc->chunk_index - 1) < 0) {
100  av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->filename);
101  return AVERROR(EINVAL);
102  }
103  }
104  return 0;
105 }
106 
108 {
109  WebMChunkContext *wc = s->priv_data;
110  AVFormatContext *oc = NULL;
111  int ret;
112 
113  // DASH Streams can only have either one track per file.
114  if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
115 
116  wc->chunk_index = wc->chunk_start_index;
117  wc->oformat = av_guess_format("webm", s->filename, "video/webm");
118  if (!wc->oformat)
120 
121  ret = chunk_mux_init(s);
122  if (ret < 0)
123  return ret;
124  oc = wc->avf;
125  ret = get_chunk_filename(s, 1, oc->filename);
126  if (ret < 0)
127  return ret;
128  ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
129  &s->interrupt_callback, NULL);
130  if (ret < 0)
131  return ret;
132 
133  oc->pb->seekable = 0;
134  ret = oc->oformat->write_header(oc);
135  if (ret < 0)
136  return ret;
137  avio_close(oc->pb);
138  return 0;
139 }
140 
142 {
143  WebMChunkContext *wc = s->priv_data;
144  AVFormatContext *oc = wc->avf;
145  int ret;
146 
147  ret = avio_open_dyn_buf(&oc->pb);
148  if (ret < 0)
149  return ret;
150  wc->chunk_index++;
151  return 0;
152 }
153 
155 {
156  WebMChunkContext *wc = s->priv_data;
157  AVFormatContext *oc = wc->avf;
158  int ret;
159  int buffer_size;
160  uint8_t *buffer;
161  AVIOContext *pb;
162  char filename[MAX_FILENAME_SIZE];
163 
164  if (wc->chunk_start_index == wc->chunk_index)
165  return 0;
166  // Flush the cluster in WebM muxer.
167  oc->oformat->write_packet(oc, NULL);
168  buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
169  ret = get_chunk_filename(s, 0, filename);
170  if (ret < 0)
171  goto fail;
172  ret = avio_open2(&pb, filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
173  if (ret < 0)
174  goto fail;
175  avio_write(pb, buffer, buffer_size);
176  ret = avio_close(pb);
177  if (ret < 0)
178  goto fail;
179  oc->pb = NULL;
180 fail:
181  av_free(buffer);
182  return (ret < 0) ? ret : 0;
183 }
184 
186 {
187  WebMChunkContext *wc = s->priv_data;
188  AVFormatContext *oc = wc->avf;
189  AVStream *st = s->streams[pkt->stream_index];
190  int ret;
191 
192  if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
193  wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
194  st->time_base,
195  (AVRational) {1, 1000});
196  wc->prev_pts = pkt->pts;
197  }
198 
199  // For video, a new chunk is started only on key frames. For audio, a new
200  // chunk is started based on chunk_duration.
201  if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
202  (pkt->flags & AV_PKT_FLAG_KEY)) ||
203  (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
204  (pkt->pts == 0 || wc->duration_written >= wc->chunk_duration))) {
205  wc->duration_written = 0;
206  if ((ret = chunk_end(s)) < 0 || (ret = chunk_start(s)) < 0) {
207  goto fail;
208  }
209  }
210 
211  ret = oc->oformat->write_packet(oc, pkt);
212  if (ret < 0)
213  goto fail;
214 
215 fail:
216  if (ret < 0) {
217  oc->streams = NULL;
218  oc->nb_streams = 0;
220  }
221 
222  return ret;
223 }
224 
226 {
227  WebMChunkContext *wc = s->priv_data;
228  AVFormatContext *oc = wc->avf;
229  oc->oformat->write_trailer(oc);
230  chunk_end(s);
231  oc->streams = NULL;
232  oc->nb_streams = 0;
234  return 0;
235 }
236 
237 #define OFFSET(x) offsetof(WebMChunkContext, x)
238 static const AVOption options[] = {
239  { "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 },
240  { "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 },
241  { "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 },
242  { NULL },
243 };
244 
245 #if CONFIG_WEBM_CHUNK_MUXER
246 static const AVClass webm_chunk_class = {
247  .class_name = "WebM Chunk Muxer",
248  .item_name = av_default_item_name,
249  .option = options,
250  .version = LIBAVUTIL_VERSION_INT,
251 };
252 
253 AVOutputFormat ff_webm_chunk_muxer = {
254  .name = "webm_chunk",
255  .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
256  .mime_type = "video/webm",
257  .extensions = "chk",
260  .priv_data_size = sizeof(WebMChunkContext),
264  .priv_class = &webm_chunk_class,
265 };
266 #endif
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
Bytestream IO Context.
Definition: avio.h:111
#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:1520
int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
Return the written size and a pointer to the buffer.
Definition: aviobuf.c:1125
AVOption.
Definition: opt.h:255
static int chunk_start(AVFormatContext *s)
Definition: webm_chunk.c:141
#define LIBAVUTIL_VERSION_INT
Definition: version.h:62
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1178
AVFormatContext * avf
Definition: webm_chunk.c:55
uint64_t duration_written
Definition: webm_chunk.c:52
#define AVIO_FLAG_WRITE
write-only
Definition: avio.h:461
int(* write_packet)(struct AVFormatContext *, AVPacket *pkt)
Write a packet.
Definition: avformat.h:564
static AVPacket pkt
int avio_open_dyn_buf(AVIOContext **s)
Open a write only memory stream.
Definition: aviobuf.c:1113
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:483
Format I/O context.
Definition: avformat.h:1272
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
uint8_t
AVOptions.
timestamp utils, mostly useful for debugging/logging purposes
#define MAX_FILENAME_SIZE
Definition: webm_chunk.c:44
static int get_chunk_filename(AVFormatContext *s, int is_header, char *filename)
Definition: webm_chunk.c:85
char * header_filename
Definition: webm_chunk.c:49
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1340
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:177
AVOutputFormat * oformat
Definition: webm_chunk.c:54
void av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags)
Copy entries from one AVDictionary struct into another.
Definition: dict.c:213
#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:285
struct AVOutputFormat * oformat
The output container format.
Definition: avformat.h:1291
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1208
int avformat_alloc_output_context2(AVFormatContext **ctx, AVOutputFormat *oformat, const char *format_name, const char *filename)
Allocate an AVFormatContext for an output format.
Definition: mux.c:148
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
Definition: mathematics.c:140
#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:1482
av_default_item_name
#define AVERROR(e)
Definition: error.h:43
static const AVOption options[]
Definition: webm_chunk.c:238
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
int(* write_header)(struct AVFormatContext *)
Definition: avformat.h:556
int avio_close(AVIOContext *s)
Close the resource accessed by the AVIOContext s and free it.
Definition: aviobuf.c:937
int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
Definition: opt.c:491
static int chunk_mux_init(AVFormatContext *s)
Definition: webm_chunk.c:58
simple assert() macros that are a bit more flexible than ISO C assert().
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
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1168
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1328
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:160
char filename[1024]
input or output filename
Definition: avformat.h:1348
ret
Definition: avfilter.c:974
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:94
#define AVFMT_GLOBALHEADER
Format wants global header.
Definition: avformat.h:471
const char * name
Definition: avformat.h:513
#define OFFSET(x)
Definition: webm_chunk.c:237
static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: webm_chunk.c:185
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:94
const AVClass * priv_class
AVClass for the private context.
Definition: avformat.h:541
int av_get_frame_filename(char *buf, int buf_size, const char *path, int number)
Return in 'buf' the path with 'd' replaced by a number.
Definition: utils.c:3831
Stream structure.
Definition: avformat.h:842
enum AVMediaType codec_type
Definition: avcodec.h:1249
AVIOContext * pb
I/O context.
Definition: avformat.h:1314
static int webm_chunk_write_header(AVFormatContext *s)
Definition: webm_chunk.c:107
Describe the class of an AVClass context structure.
Definition: log.h:67
rational number numerator/denominator
Definition: rational.h:43
int avio_open2(AVIOContext **s, const char *url, int flags, const AVIOInterruptCB *int_cb, AVDictionary **options)
Create and initialize a AVIOContext for accessing the resource indicated by url.
Definition: aviobuf.c:914
void avformat_free_context(AVFormatContext *s)
Free an AVFormatContext and all its streams.
Definition: utils.c:3609
misc parsing utilities
static int chunk_end(AVFormatContext *s)
Definition: webm_chunk.c:154
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:465
static int webm_chunk_write_trailer(AVFormatContext *s)
Definition: webm_chunk.c:225
#define av_free(p)
void * priv_data
Format private data.
Definition: avformat.h:1300
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:493
#define AVERROR_MUXER_NOT_FOUND
Muxer not found.
Definition: error.h:60
int stream_index
Definition: avcodec.h:1164
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:884
This structure stores compressed data.
Definition: avcodec.h:1139
int(* write_trailer)(struct AVFormatContext *)
Definition: avformat.h:565
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:86
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1155
GLuint buffer
Definition: opengl_enc.c:102
#define AVFMT_NEEDNUMBER
Needs 'd' in filename.
Definition: avformat.h:466