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1/*
2 * Copyright (c) 2015, Vignesh Venkatasubramanian
3 *
4 * This file is part of FFmpeg.
5 *
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.
10 *
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.
15 *
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
19 */
20
21/**
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.
25 */
26
27#include <float.h>
28#include <time.h>
29
30#include "avformat.h"
31#include "avio.h"
32#include "avio_internal.h"
33#include "internal.h"
34
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"
44
45#define MAX_FILENAME_SIZE 1024
46
47typedef struct WebMChunkContext {
48 const AVClass *class;
49 int chunk_start_index;
50 char *header_filename;
51 int chunk_duration;
52 int chunk_index;
53 char *http_method;
54 uint64_t duration_written;
55 int prev_pts;
56 AVOutputFormat *oformat;
57 AVFormatContext *avf;
58} WebMChunkContext;
59
60static int chunk_mux_init(AVFormatContext *s)
61{
62 WebMChunkContext *wc = s->priv_data;
63 AVFormatContext *oc;
64 int ret;
65
66 ret = avformat_alloc_output_context2(&wc->avf, wc->oformat, NULL, NULL);
67 if (ret < 0)
68 return ret;
69 oc = wc->avf;
70
71 oc->interrupt_callback = s->interrupt_callback;
72 oc->max_delay = s->max_delay;
73 av_dict_copy(&oc->metadata, s->metadata, 0);
74
75 *(const AVClass**)oc->priv_data = oc->oformat->priv_class;
76 av_opt_set_defaults(oc->priv_data);
77 av_opt_set_int(oc->priv_data, "dash", 1, 0);
78 av_opt_set_int(oc->priv_data, "cluster_time_limit", wc->chunk_duration, 0);
79 av_opt_set_int(oc->priv_data, "live", 1, 0);
80
81 oc->streams = s->streams;
82 oc->nb_streams = s->nb_streams;
83
84 return 0;
85}
86
87static int get_chunk_filename(AVFormatContext *s, int is_header, char *filename)
88{
89 WebMChunkContext *wc = s->priv_data;
90 AVFormatContext *oc = wc->avf;
91 if (!filename) {
92 return AVERROR(EINVAL);
93 }
94 if (is_header) {
95 if (!wc->header_filename) {
96 av_log(oc, AV_LOG_ERROR, "No header filename provided\n");
97 return AVERROR(EINVAL);
98 }
99 av_strlcpy(filename, wc->header_filename, strlen(wc->header_filename) + 1);
100 } else {
101 if (av_get_frame_filename(filename, MAX_FILENAME_SIZE,
102 s->filename, wc->chunk_index - 1) < 0) {
103 av_log(oc, AV_LOG_ERROR, "Invalid chunk filename template '%s'\n", s->filename);
104 return AVERROR(EINVAL);
105 }
106 }
107 return 0;
108}
109
110static int webm_chunk_write_header(AVFormatContext *s)
111{
112 WebMChunkContext *wc = s->priv_data;
113 AVFormatContext *oc = NULL;
114 int ret;
115 int i;
116 AVDictionary *options = NULL;
117
118 // DASH Streams can only have either one track per file.
119 if (s->nb_streams != 1) { return AVERROR_INVALIDDATA; }
120
121 wc->chunk_index = wc->chunk_start_index;
122 wc->oformat = av_guess_format("webm", s->filename, "video/webm");
123 if (!wc->oformat)
124 return AVERROR_MUXER_NOT_FOUND;
125
126 ret = chunk_mux_init(s);
127 if (ret < 0)
128 return ret;
129 oc = wc->avf;
130 ret = get_chunk_filename(s, 1, oc->filename);
131 if (ret < 0)
132 return ret;
133 if (wc->http_method)
134 av_dict_set(&options, "method", wc->http_method, 0);
135 ret = s->io_open(s, &oc->pb, oc->filename, AVIO_FLAG_WRITE, &options);
136 av_dict_free(&options);
137 if (ret < 0)
138 return ret;
139
140 oc->pb->seekable = 0;
141 ret = oc->oformat->write_header(oc);
142 if (ret < 0)
143 return ret;
144 ff_format_io_close(s, &oc->pb);
145 for (i = 0; i < s->nb_streams; i++) {
146 // ms precision is the de-facto standard timescale for mkv files.
147 avpriv_set_pts_info(s->streams[i], 64, 1, 1000);
148 }
149 return 0;
150}
151
152static int chunk_start(AVFormatContext *s)
153{
154 WebMChunkContext *wc = s->priv_data;
155 AVFormatContext *oc = wc->avf;
156 int ret;
157
158 ret = avio_open_dyn_buf(&oc->pb);
159 if (ret < 0)
160 return ret;
161 wc->chunk_index++;
162 return 0;
163}
164
165static int chunk_end(AVFormatContext *s)
166{
167 WebMChunkContext *wc = s->priv_data;
168 AVFormatContext *oc = wc->avf;
169 int ret;
170 int buffer_size;
171 uint8_t *buffer;
172 AVIOContext *pb;
173 char filename[MAX_FILENAME_SIZE];
174 AVDictionary *options = NULL;
175
176 if (wc->chunk_start_index == wc->chunk_index)
177 return 0;
178 // Flush the cluster in WebM muxer.
179 oc->oformat->write_packet(oc, NULL);
180 buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
181 ret = get_chunk_filename(s, 0, filename);
182 if (ret < 0)
183 goto fail;
184 if (wc->http_method)
185 av_dict_set(&options, "method", wc->http_method, 0);
186 ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
187 if (ret < 0)
188 goto fail;
189 avio_write(pb, buffer, buffer_size);
190 ff_format_io_close(s, &pb);
191 oc->pb = NULL;
192fail:
193 av_dict_free(&options);
194 av_free(buffer);
195 return (ret < 0) ? ret : 0;
196}
197
198static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
199{
200 WebMChunkContext *wc = s->priv_data;
201 AVFormatContext *oc = wc->avf;
202 AVStream *st = s->streams[pkt->stream_index];
203 int ret;
204
205 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
206 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
207 st->time_base,
208 (AVRational) {1, 1000});
209 wc->prev_pts = pkt->pts;
210 }
211
212 // For video, a new chunk is started only on key frames. For audio, a new
213 // chunk is started based on chunk_duration.
214 if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
215 (pkt->flags & AV_PKT_FLAG_KEY)) ||
216 (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
217 (pkt->pts == 0 || wc->duration_written >= wc->chunk_duration))) {
218 wc->duration_written = 0;
219 if ((ret = chunk_end(s)) < 0 || (ret = chunk_start(s)) < 0) {
220 goto fail;
221 }
222 }
223
224 ret = oc->oformat->write_packet(oc, pkt);
225 if (ret < 0)
226 goto fail;
227
228fail:
229 if (ret < 0) {
230 oc->streams = NULL;
231 oc->nb_streams = 0;
232 avformat_free_context(oc);
233 }
234
235 return ret;
236}
237
238static int webm_chunk_write_trailer(AVFormatContext *s)
239{
240 WebMChunkContext *wc = s->priv_data;
241 AVFormatContext *oc = wc->avf;
242 oc->oformat->write_trailer(oc);
243 chunk_end(s);
244 oc->streams = NULL;
245 oc->nb_streams = 0;
246 avformat_free_context(oc);
247 return 0;
248}
249
250#define OFFSET(x) offsetof(WebMChunkContext, x)
251static const AVOption options[] = {
252 { "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 },
253 { "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 },
254 { "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 },
255 { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
256 { NULL },
257};
258
259#if CONFIG_WEBM_CHUNK_MUXER
260static const AVClass webm_chunk_class = {
261 .class_name = "WebM Chunk Muxer",
262 .item_name = av_default_item_name,
263 .option = options,
264 .version = LIBAVUTIL_VERSION_INT,
265};
266
267AVOutputFormat ff_webm_chunk_muxer = {
268 .name = "webm_chunk",
269 .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
270 .mime_type = "video/webm",
271 .extensions = "chk",
272 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
273 AVFMT_TS_NONSTRICT,
274 .priv_data_size = sizeof(WebMChunkContext),
275 .write_header = webm_chunk_write_header,
276 .write_packet = webm_chunk_write_packet,
277 .write_trailer = webm_chunk_write_trailer,
278 .priv_class = &webm_chunk_class,
279};
280#endif
281
generated by cgit at 2024-05-17 03:40:26 (GMT)