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.
32 #include "avio_internal.h"
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"
42 #include "libavutil/time_internal.h"
43 #include "libavutil/timestamp.h"
45 #define MAX_FILENAME_SIZE 1024
47 typedef struct WebMChunkContext {
49 int chunk_start_index;
50 char *header_filename;
53 uint64_t duration_written;
55 AVOutputFormat *oformat;
59 static int chunk_mux_init(AVFormatContext *s)
61 WebMChunkContext *wc = s->priv_data;
65 ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
70 oc->interrupt_callback = s->interrupt_callback;
71 oc->max_delay = s->max_delay;
72 av_dict_copy(&oc->metadata, s->metadata, 0);
74 *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
75 av_opt_set_defaults(oc->priv_data);
76 av_opt_set_int(oc->priv_data, "dash", 1, 0);
77 av_opt_set_int(oc->priv_data, "cluster_time_limit", wc->chunk_duration, 0);
78 av_opt_set_int(oc->priv_data, "live", 1, 0);
80 oc->streams = s->streams;
81 oc->nb_streams = s->nb_streams;
86 static int get_chunk_filename(AVFormatContext *s, int is_header, char *filename)
88 WebMChunkContext *wc = s->priv_data;
89 AVFormatContext *oc = wc->avf;
91 return AVERROR(EINVAL);
94 if (!wc->header_filename) {
95 return AVERROR(EINVAL);
97 av_strlcpy(filename, wc->header_filename, strlen(wc->header_filename) + 1);
99 if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
100 s->filename, wc->chunk_index - 1) < 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; }
117 wc->chunk_index = wc->chunk_start_index;
118 wc->oformat = av_guess_format("webm", s->filename, "video/webm");
120 return AVERROR_MUXER_NOT_FOUND;
122 ret = chunk_mux_init(s);
126 ret = get_chunk_filename(s, 1, oc->filename);
129 ret = s->io_open(s, &oc->pb, oc->filename, AVIO_FLAG_WRITE, NULL);
133 oc->pb->seekable = 0;
134 ret = oc->oformat->write_header(oc);
137 ff_format_io_close(s, &oc->pb);
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 = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, NULL);
175 avio_write(pb, buffer, buffer_size);
176 ff_format_io_close(s, &pb);
180 return (ret < 0) ? ret : 0;
183 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
185 WebMChunkContext *wc = s->priv_data;
186 AVFormatContext *oc = wc->avf;
187 AVStream *st = s->streams[pkt->stream_index];
190 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
191 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
193 (AVRational) {1, 1000});
194 wc->prev_pts = pkt->pts;
197 // For video, a new chunk is started only on key frames. For audio, a new
198 // chunk is started based on chunk_duration.
199 if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
200 (pkt->flags & AV_PKT_FLAG_KEY)) ||
201 (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
202 (pkt->pts == 0 || wc->duration_written >= wc->chunk_duration))) {
203 wc->duration_written = 0;
204 if ((ret = chunk_end(s)) < 0 || (ret = chunk_start(s)) < 0) {
209 ret = oc->oformat->write_packet(oc, pkt);
217 avformat_free_context(oc);
223 static int webm_chunk_write_trailer(AVFormatContext *s)
225 WebMChunkContext *wc = s->priv_data;
226 AVFormatContext *oc = wc->avf;
227 oc->oformat->write_trailer(oc);
231 avformat_free_context(oc);
235 #define OFFSET(x) offsetof(WebMChunkContext, x)
236 static const AVOption options[] = {
237 { "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 },
238 { "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 },
239 { "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 },
243 #if CONFIG_WEBM_CHUNK_MUXER
244 static const AVClass webm_chunk_class = {
245 .class_name = "WebM Chunk Muxer",
246 .item_name = av_default_item_name,
248 .version = LIBAVUTIL_VERSION_INT,
251 AVOutputFormat ff_webm_chunk_muxer = {
252 .name = "webm_chunk",
253 .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
254 .mime_type = "video/webm",
256 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
258 .priv_data_size = sizeof(WebMChunkContext),
259 .write_header = webm_chunk_write_header,
260 .write_packet = webm_chunk_write_packet,
261 .write_trailer = webm_chunk_write_trailer,
262 .priv_class = &webm_chunk_class,