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 typedef struct WebMChunkContext {
46 int chunk_start_index;
47 char *header_filename;
51 uint64_t duration_written;
53 AVOutputFormat *oformat;
57 static int chunk_mux_init(AVFormatContext *s)
59 WebMChunkContext *wc = s->priv_data;
63 ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
68 oc->interrupt_callback = s->interrupt_callback;
69 oc->max_delay = s->max_delay;
70 av_dict_copy(&oc->metadata, s->metadata, 0);
72 oc->priv_data = av_mallocz(oc->oformat->priv_data_size);
75 return AVERROR(ENOMEM);
77 *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
78 av_opt_set_defaults(oc->priv_data);
79 av_opt_set_int(oc->priv_data, "dash", 1, 0);
80 av_opt_set_int(oc->priv_data, "cluster_time_limit", wc->chunk_duration, 0);
81 av_opt_set_int(oc->priv_data, "live", 1, 0);
83 oc->streams = s->streams;
84 oc->nb_streams = s->nb_streams;
89 static int set_chunk_filename(AVFormatContext *s, int is_header)
91 WebMChunkContext *wc = s->priv_data;
92 AVFormatContext *oc = wc->avf;
94 if (!wc->header_filename) {
95 return AVERROR(EINVAL);
97 av_strlcpy(oc->filename, wc->header_filename, strlen(wc->header_filename) + 1);
99 if (av_get_frame_filename(oc->filename, sizeof(oc->filename),
100 s->filename, wc->chunk_index) < 0) {
101 av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->filename);
102 return AVERROR(EINVAL);
108 static int webm_chunk_write_header(AVFormatContext *s)
110 WebMChunkContext *wc = s->priv_data;
111 AVFormatContext *oc = NULL;
114 // DASH Streams can only have either one track per file.
115 if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
118 wc->chunk_index = wc->chunk_start_index;
119 wc->oformat = av_guess_format("webm", s->filename, "video/webm");
121 return AVERROR_MUXER_NOT_FOUND;
123 ret = chunk_mux_init(s);
127 ret = set_chunk_filename(s, 1);
130 ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
131 &s->interrupt_callback, NULL);
135 oc->pb->seekable = 0;
136 ret = oc->oformat->write_header(oc);
143 static int chunk_start(AVFormatContext *s)
145 WebMChunkContext *wc = s->priv_data;
146 AVFormatContext *oc = wc->avf;
149 ret = set_chunk_filename(s, 0);
153 ret = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
154 &s->interrupt_callback, NULL);
157 oc->pb->seekable = 0;
161 static int chunk_end(AVFormatContext *s)
163 WebMChunkContext *wc = s->priv_data;
164 AVFormatContext *oc = wc->avf;
167 if (wc->chunk_start_index == wc->chunk_index)
169 // Flush the cluster in WebM muxer.
170 oc->oformat->write_packet(oc, NULL);
171 ret = avio_close(oc->pb);
178 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
180 WebMChunkContext *wc = s->priv_data;
181 AVFormatContext *oc = wc->avf;
182 AVStream *st = s->streams[pkt->stream_index];
185 if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
186 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
188 (AVRational) {1, 1000});
189 wc->prev_pts = pkt->pts;
192 // For video, a new chunk is started only on key frames. For audio, a new
193 // chunk is started based on chunk_duration.
194 if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
195 (pkt->flags & AV_PKT_FLAG_KEY)) ||
196 (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
197 (pkt->pts == 0 || wc->duration_written >= wc->chunk_duration))) {
198 wc->duration_written = 0;
199 if ((ret = chunk_end(s)) < 0 || (ret = chunk_start(s)) < 0) {
204 if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && pkt->pts == 0) {
207 ret = oc->oformat->write_packet(oc, pkt);
215 avformat_free_context(oc);
221 static int webm_chunk_write_trailer(AVFormatContext *s)
223 WebMChunkContext *wc = s->priv_data;
224 AVFormatContext *oc = wc->avf;
225 oc->oformat->write_trailer(oc);
229 avformat_free_context(oc);
233 #define OFFSET(x) offsetof(WebMChunkContext, x)
234 static const AVOption options[] = {
235 { "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 },
236 { "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 },
237 { "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 },
241 #if CONFIG_WEBM_CHUNK_MUXER
242 static const AVClass webm_chunk_class = {
243 .class_name = "WebM Chunk Muxer",
244 .item_name = av_default_item_name,
246 .version = LIBAVUTIL_VERSION_INT,
249 AVOutputFormat ff_webm_chunk_muxer = {
250 .name = "webm_chunk",
251 .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
252 .mime_type = "video/webm",
254 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
255 AVFMT_TS_NONSTRICT | AVFMT_ALLOW_FLUSH,
256 .priv_data_size = sizeof(WebMChunkContext),
257 .write_header = webm_chunk_write_header,
258 .write_packet = webm_chunk_write_packet,
259 .write_trailer = webm_chunk_write_trailer,
260 .priv_class = &webm_chunk_class,