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 char *header_filename;
53 uint64_t duration_written;
58 static int webm_chunk_init(AVFormatContext *s)
60 WebMChunkContext *wc = s->priv_data;
61 ff_const59 AVOutputFormat *oformat;
63 AVStream *st, *ost = s->streams[0];
64 AVDictionary *dict = NULL;
67 // DASH Streams can only have one track per file.
68 if (s->nb_streams != 1)
69 return AVERROR(EINVAL);
71 if (!wc->header_filename) {
72 av_log(s, AV_LOG_ERROR, "No header filename provided\n");
73 return AVERROR(EINVAL);
76 wc->prev_pts = AV_NOPTS_VALUE;
78 oformat = av_guess_format("webm", s->url, "video/webm");
80 return AVERROR_MUXER_NOT_FOUND;
82 ret = avformat_alloc_output_context2(&wc->avf, oformat, NULL, NULL);
87 ff_format_set_url(oc, wc->header_filename);
88 wc->header_filename = NULL;
90 oc->interrupt_callback = s->interrupt_callback;
91 oc->max_delay = s->max_delay;
92 oc->flags = s->flags & ~AVFMT_FLAG_FLUSH_PACKETS;
93 oc->strict_std_compliance = s->strict_std_compliance;
94 oc->avoid_negative_ts = s->avoid_negative_ts;
96 oc->flush_packets = 0;
98 av_dict_copy(&oc->metadata, s->metadata, 0);
100 if (!(st = avformat_new_stream(oc, NULL)))
101 return AVERROR(ENOMEM);
103 if ((ret = avcodec_parameters_copy(st->codecpar, ost->codecpar)) < 0 ||
104 (ret = av_dict_copy(&st->metadata, ost->metadata, 0)) < 0)
107 st->sample_aspect_ratio = ost->sample_aspect_ratio;
108 st->disposition = ost->disposition;
109 avpriv_set_pts_info(st, ost->pts_wrap_bits, ost->time_base.num,
112 av_dict_set_int(&dict, "dash", 1, 0);
113 av_dict_set_int(&dict, "cluster_time_limit", wc->chunk_duration, 0);
114 av_dict_set_int(&dict, "live", 1, 0);
116 ret = avformat_init_output(oc, &dict);
121 // Copy the timing info back to the original stream
122 // so that the timestamps of the packets are directly usable
123 avpriv_set_pts_info(ost, st->pts_wrap_bits, st->time_base.num,
126 // This ensures that the timestamps will already be properly shifted
127 // when the packets arrive here, so we don't need to shift again.
128 s->avoid_negative_ts = oc->avoid_negative_ts;
129 s->internal->avoid_negative_ts_use_pts =
130 oc->internal->avoid_negative_ts_use_pts;
131 oc->avoid_negative_ts = 0;
136 static int get_chunk_filename(AVFormatContext *s, char filename[MAX_FILENAME_SIZE])
138 WebMChunkContext *wc = s->priv_data;
140 return AVERROR(EINVAL);
142 if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
143 s->url, wc->chunk_index - 1) < 0) {
144 av_log(s, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
145 return AVERROR(EINVAL);
150 static int webm_chunk_write_header(AVFormatContext *s)
152 WebMChunkContext *wc = s->priv_data;
153 AVFormatContext *oc = wc->avf;
155 AVDictionary *options = NULL;
158 av_dict_set(&options, "method", wc->http_method, 0);
159 ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &options);
160 av_dict_free(&options);
164 oc->pb->seekable = 0;
165 ret = avformat_write_header(oc, NULL);
166 ff_format_io_close(s, &oc->pb);
172 static int chunk_start(AVFormatContext *s)
174 WebMChunkContext *wc = s->priv_data;
175 AVFormatContext *oc = wc->avf;
178 ret = avio_open_dyn_buf(&oc->pb);
185 static int chunk_end(AVFormatContext *s, int flush)
187 WebMChunkContext *wc = s->priv_data;
188 AVFormatContext *oc = wc->avf;
193 char filename[MAX_FILENAME_SIZE];
194 AVDictionary *options = NULL;
200 // Flush the cluster in WebM muxer.
201 av_write_frame(oc, NULL);
202 buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
204 ret = get_chunk_filename(s, filename);
208 av_dict_set(&options, "method", wc->http_method, 0);
209 ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
212 avio_write(pb, buffer, buffer_size);
213 ff_format_io_close(s, &pb);
215 av_dict_free(&options);
217 return (ret < 0) ? ret : 0;
220 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
222 WebMChunkContext *wc = s->priv_data;
223 AVFormatContext *oc = wc->avf;
224 AVStream *st = s->streams[pkt->stream_index];
227 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
228 if (wc->prev_pts != AV_NOPTS_VALUE)
229 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
231 (AVRational) {1, 1000});
232 wc->prev_pts = pkt->pts;
235 // For video, a new chunk is started only on key frames. For audio, a new
236 // chunk is started based on chunk_duration. Also, a new chunk is started
237 // unconditionally if there is no currently open chunk.
238 if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
239 (pkt->flags & AV_PKT_FLAG_KEY)) ||
240 (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
241 wc->duration_written >= wc->chunk_duration)) {
242 wc->duration_written = 0;
243 if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
248 // We only have one stream, so use the non-interleaving av_write_frame.
249 return av_write_frame(oc, pkt);
252 static int webm_chunk_write_trailer(AVFormatContext *s)
254 WebMChunkContext *wc = s->priv_data;
255 AVFormatContext *oc = wc->avf;
259 ret = chunk_start(s);
263 av_write_trailer(oc);
264 ret = chunk_end(s, 0);
266 avformat_free_context(oc);
270 #define OFFSET(x) offsetof(WebMChunkContext, x)
271 static const AVOption options[] = {
272 { "chunk_start_index", "start index of the chunk", OFFSET(chunk_index), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
273 { "header", "filename of the header where the initialization data will be written", OFFSET(header_filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
274 { "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 },
275 { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
279 #if CONFIG_WEBM_CHUNK_MUXER
280 static const AVClass webm_chunk_class = {
281 .class_name = "WebM Chunk Muxer",
282 .item_name = av_default_item_name,
284 .version = LIBAVUTIL_VERSION_INT,
287 AVOutputFormat ff_webm_chunk_muxer = {
288 .name = "webm_chunk",
289 .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
290 .mime_type = "video/webm",
292 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
294 .priv_data_size = sizeof(WebMChunkContext),
295 .init = webm_chunk_init,
296 .write_header = webm_chunk_write_header,
297 .write_packet = webm_chunk_write_packet,
298 .write_trailer = webm_chunk_write_trailer,
299 .priv_class = &webm_chunk_class,