2 * Copyright (c) 2015, Vignesh Venkatasubramanian
4 * This file is part of FFmpeg.
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.
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.
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
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.
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"
41 #include "libavutil/time_internal.h"
42 #include "libavutil/timestamp.h"
44 #define MAX_FILENAME_SIZE 1024
46 typedef struct WebMChunkContext {
48 int chunk_start_index;
49 char *header_filename;
52 uint64_t duration_written;
54 AVOutputFormat *oformat;
58 static int chunk_mux_init(AVFormatContext *s)
60 WebMChunkContext *wc = s->priv_data;
64 ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
69 oc->interrupt_callback = s->interrupt_callback;
70 oc->max_delay = s->max_delay;
71 av_dict_copy(&oc->metadata, s->metadata, 0);
73 *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
74 av_opt_set_defaults(oc->priv_data);
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);
79 oc->streams = s->streams;
80 oc->nb_streams = s->nb_streams;
85 static int get_chunk_filename(AVFormatContext *s, int is_header, char *filename)
87 WebMChunkContext *wc = s->priv_data;
88 AVFormatContext *oc = wc->avf;
90 return AVERROR(EINVAL);
93 if (!wc->header_filename) {
94 return AVERROR(EINVAL);
96 av_strlcpy(filename, wc->header_filename, strlen(wc->header_filename) + 1);
98 if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
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);
107 static int webm_chunk_write_header(AVFormatContext *s)
109 WebMChunkContext *wc = s->priv_data;
110 AVFormatContext *oc = NULL;
113 // DASH Streams can only have either one track per file.
114 if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
116 wc->chunk_index = wc->chunk_start_index;
117 wc->oformat = av_guess_format("webm", s->filename, "video/webm");
119 return AVERROR_MUXER_NOT_FOUND;
121 ret = chunk_mux_init(s);
125 ret = get_chunk_filename(s, 1, oc->filename);
128 ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
129 &s->interrupt_callback, NULL);
133 oc->pb->seekable = 0;
134 ret = oc->oformat->write_header(oc);
141 static int chunk_start(AVFormatContext *s)
143 WebMChunkContext *wc = s->priv_data;
144 AVFormatContext *oc = wc->avf;
147 ret = avio_open_dyn_buf(&oc->pb);
154 static int chunk_end(AVFormatContext *s)
156 WebMChunkContext *wc = s->priv_data;
157 AVFormatContext *oc = wc->avf;
162 char filename[MAX_FILENAME_SIZE];
164 if (wc->chunk_start_index == wc->chunk_index)
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);
172 ret = avio_open2(&pb, filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
175 avio_write(pb, buffer, buffer_size);
176 ret = avio_close(pb);
182 return (ret < 0) ? ret : 0;
185 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
187 WebMChunkContext *wc = s->priv_data;
188 AVFormatContext *oc = wc->avf;
189 AVStream *st = s->streams[pkt->stream_index];
192 if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
193 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
195 (AVRational) {1, 1000});
196 wc->prev_pts = pkt->pts;
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) {
211 ret = oc->oformat->write_packet(oc, pkt);
219 avformat_free_context(oc);
225 static int webm_chunk_write_trailer(AVFormatContext *s)
227 WebMChunkContext *wc = s->priv_data;
228 AVFormatContext *oc = wc->avf;
229 oc->oformat->write_trailer(oc);
233 avformat_free_context(oc);
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 },
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,
250 .version = LIBAVUTIL_VERSION_INT,
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",
258 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
260 .priv_data_size = sizeof(WebMChunkContext),
261 .write_header = webm_chunk_write_header,
262 .write_packet = webm_chunk_write_packet,
263 .write_trailer = webm_chunk_write_trailer,
264 .priv_class = &webm_chunk_class,