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;
54 uint64_t duration_written;
56 ff_const59 AVOutputFormat *oformat;
60 static int chunk_mux_init(AVFormatContext *s)
62 WebMChunkContext *wc = s->priv_data;
64 AVStream *st, *ost = s->streams[0];
65 AVDictionary *dict = NULL;
68 ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
73 oc->interrupt_callback = s->interrupt_callback;
74 oc->max_delay = s->max_delay;
76 oc->strict_std_compliance = s->strict_std_compliance;
77 oc->avoid_negative_ts = s->avoid_negative_ts;
79 av_dict_copy(&oc->metadata, s->metadata, 0);
81 if (!(st = avformat_new_stream(oc, NULL)))
82 return AVERROR(ENOMEM);
84 if ((ret = avcodec_parameters_copy(st->codecpar, ost->codecpar)) < 0 ||
85 (ret = av_dict_copy(&st->metadata, ost->metadata, 0)) < 0)
88 st->sample_aspect_ratio = ost->sample_aspect_ratio;
89 st->disposition = ost->disposition;
90 avpriv_set_pts_info(st, ost->pts_wrap_bits, ost->time_base.num,
93 av_dict_set_int(&dict, "dash", 1, 0);
94 av_dict_set_int(&dict, "cluster_time_limit", wc->chunk_duration, 0);
95 av_dict_set_int(&dict, "live", 1, 0);
97 ret = avformat_init_output(oc, &dict);
102 // Copy the timing info back to the original stream
103 // so that the timestamps of the packets are directly usable
104 avpriv_set_pts_info(ost, st->pts_wrap_bits, st->time_base.num,
107 // This ensures that the timestamps will already be properly shifted
108 // when the packets arrive here, so we don't need to shift again.
109 s->avoid_negative_ts = oc->avoid_negative_ts;
110 s->internal->avoid_negative_ts_use_pts =
111 oc->internal->avoid_negative_ts_use_pts;
112 oc->avoid_negative_ts = 0;
117 static int get_chunk_filename(AVFormatContext *s, int is_header, char filename[MAX_FILENAME_SIZE])
119 WebMChunkContext *wc = s->priv_data;
121 return AVERROR(EINVAL);
125 if (!wc->header_filename) {
126 av_log(s, AV_LOG_ERROR, "No header filename provided\n");
127 return AVERROR(EINVAL);
129 len = av_strlcpy(filename, wc->header_filename, MAX_FILENAME_SIZE);
130 if (len >= MAX_FILENAME_SIZE) {
131 av_log(s, AV_LOG_ERROR, "Header filename too long\n");
132 return AVERROR(EINVAL);
135 if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
136 s->url, wc->chunk_index - 1) < 0) {
137 av_log(s, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->url);
138 return AVERROR(EINVAL);
144 static int webm_chunk_write_header(AVFormatContext *s)
146 WebMChunkContext *wc = s->priv_data;
147 AVFormatContext *oc = NULL;
149 AVDictionary *options = NULL;
150 char oc_filename[MAX_FILENAME_SIZE];
153 // DASH Streams can only have either one track per file.
154 if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
156 wc->chunk_index = wc->chunk_start_index;
157 wc->oformat = av_guess_format("webm", s->url, "video/webm");
159 return AVERROR_MUXER_NOT_FOUND;
160 wc->prev_pts = AV_NOPTS_VALUE;
162 ret = chunk_mux_init(s);
166 ret = get_chunk_filename(s, 1, oc_filename);
169 oc_url = av_strdup(oc_filename);
171 return AVERROR(ENOMEM);
172 ff_format_set_url(oc, oc_url);
174 av_dict_set(&options, "method", wc->http_method, 0);
175 ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &options);
176 av_dict_free(&options);
180 oc->pb->seekable = 0;
181 ret = avformat_write_header(oc, NULL);
182 ff_format_io_close(s, &oc->pb);
188 static int chunk_start(AVFormatContext *s)
190 WebMChunkContext *wc = s->priv_data;
191 AVFormatContext *oc = wc->avf;
194 ret = avio_open_dyn_buf(&oc->pb);
201 static int chunk_end(AVFormatContext *s, int flush)
203 WebMChunkContext *wc = s->priv_data;
204 AVFormatContext *oc = wc->avf;
209 char filename[MAX_FILENAME_SIZE];
210 AVDictionary *options = NULL;
216 // Flush the cluster in WebM muxer.
217 av_write_frame(oc, NULL);
218 buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
220 ret = get_chunk_filename(s, 0, filename);
224 av_dict_set(&options, "method", wc->http_method, 0);
225 ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
228 avio_write(pb, buffer, buffer_size);
229 ff_format_io_close(s, &pb);
231 av_dict_free(&options);
233 return (ret < 0) ? ret : 0;
236 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
238 WebMChunkContext *wc = s->priv_data;
239 AVFormatContext *oc = wc->avf;
240 AVStream *st = s->streams[pkt->stream_index];
243 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
244 if (wc->prev_pts != AV_NOPTS_VALUE)
245 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
247 (AVRational) {1, 1000});
248 wc->prev_pts = pkt->pts;
251 // For video, a new chunk is started only on key frames. For audio, a new
252 // chunk is started based on chunk_duration. Also, a new chunk is started
253 // unconditionally if there is no currently open chunk.
254 if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
255 (pkt->flags & AV_PKT_FLAG_KEY)) ||
256 (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
257 wc->duration_written >= wc->chunk_duration)) {
258 wc->duration_written = 0;
259 if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
264 // We only have one stream, so use the non-interleaving av_write_frame.
265 return av_write_frame(oc, pkt);
268 static int webm_chunk_write_trailer(AVFormatContext *s)
270 WebMChunkContext *wc = s->priv_data;
271 AVFormatContext *oc = wc->avf;
275 ret = chunk_start(s);
279 av_write_trailer(oc);
280 ret = chunk_end(s, 0);
282 avformat_free_context(oc);
286 #define OFFSET(x) offsetof(WebMChunkContext, x)
287 static const AVOption options[] = {
288 { "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 },
289 { "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 },
290 { "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 },
291 { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
295 #if CONFIG_WEBM_CHUNK_MUXER
296 static const AVClass webm_chunk_class = {
297 .class_name = "WebM Chunk Muxer",
298 .item_name = av_default_item_name,
300 .version = LIBAVUTIL_VERSION_INT,
303 AVOutputFormat ff_webm_chunk_muxer = {
304 .name = "webm_chunk",
305 .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
306 .mime_type = "video/webm",
308 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
310 .priv_data_size = sizeof(WebMChunkContext),
311 .write_header = webm_chunk_write_header,
312 .write_packet = webm_chunk_write_packet,
313 .write_trailer = webm_chunk_write_trailer,
314 .priv_class = &webm_chunk_class,