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 "avformat.h"
28 #include "avio.h"
29 #include "avio_internal.h"
30 #include "internal.h"
31 #include "mux.h"
32
33 #include "libavutil/log.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/mathematics.h"
36
37 #define MAX_FILENAME_SIZE 1024
38
39 typedef struct WebMChunkContext {
40 const AVClass *class;
41 char *header_filename;
42 int chunk_duration;
43 int chunk_index;
44 char *http_method;
45 uint64_t duration_written;
46 int64_t prev_pts;
47 AVFormatContext *avf;
48 int header_written;
49 } WebMChunkContext;
50
webm_chunk_init(AVFormatContext * s)51 static int webm_chunk_init(AVFormatContext *s)
52 {
53 WebMChunkContext *wc = s->priv_data;
54 const AVOutputFormat *oformat;
55 AVFormatContext *oc;
56 AVStream *st, *ost = s->streams[0];
57 AVDictionary *dict = NULL;
58 int ret;
59
60 // DASH Streams can only have one track per file.
61 if (s->nb_streams != 1)
62 return AVERROR(EINVAL);
63
64 if (!wc->header_filename) {
65 av_log(s, AV_LOG_ERROR, "No header filename provided\n");
66 return AVERROR(EINVAL);
67 }
68
69 wc->prev_pts = AV_NOPTS_VALUE;
70
71 oformat = av_guess_format("webm", s->url, "video/webm");
72 if (!oformat)
73 return AVERROR_MUXER_NOT_FOUND;
74
75 ret = avformat_alloc_output_context2(&wc->avf, oformat, NULL, NULL);
76 if (ret < 0)
77 return ret;
78 oc = wc->avf;
79
80 ff_format_set_url(oc, wc->header_filename);
81 wc->header_filename = NULL;
82
83 oc->interrupt_callback = s->interrupt_callback;
84 oc->max_delay = s->max_delay;
85 oc->flags = s->flags & ~AVFMT_FLAG_FLUSH_PACKETS;
86 oc->strict_std_compliance = s->strict_std_compliance;
87 oc->avoid_negative_ts = s->avoid_negative_ts;
88
89 oc->flush_packets = 0;
90
91 if ((ret = av_dict_copy(&oc->metadata, s->metadata, 0)) < 0)
92 return ret;
93
94 if (!(st = avformat_new_stream(oc, NULL)))
95 return AVERROR(ENOMEM);
96
97 if ((ret = ff_stream_encode_params_copy(st, ost)) < 0)
98 return ret;
99
100 if (wc->http_method)
101 if ((ret = av_dict_set(&dict, "method", wc->http_method, 0)) < 0)
102 return ret;
103 ret = s->io_open(s, &oc->pb, oc->url, AVIO_FLAG_WRITE, &dict);
104 av_dict_free(&dict);
105 if (ret < 0)
106 return ret;
107 oc->pb->seekable = 0;
108
109 if ((ret = av_dict_set_int(&dict, "dash", 1, 0)) < 0 ||
110 (ret = av_dict_set_int(&dict, "cluster_time_limit",
111 wc->chunk_duration, 0)) < 0 ||
112 (ret = av_dict_set_int(&dict, "live", 1, 0)) < 0)
113 goto fail;
114
115 ret = avformat_init_output(oc, &dict);
116 fail:
117 av_dict_free(&dict);
118 if (ret < 0)
119 return ret;
120
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,
124 st->time_base.den);
125
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 ffformatcontext(s)->avoid_negative_ts_use_pts =
130 ffformatcontext(oc)->avoid_negative_ts_use_pts;
131 oc->avoid_negative_ts = AVFMT_AVOID_NEG_TS_DISABLED;
132
133 return 0;
134 }
135
get_chunk_filename(AVFormatContext * s,char filename[MAX_FILENAME_SIZE])136 static int get_chunk_filename(AVFormatContext *s, char filename[MAX_FILENAME_SIZE])
137 {
138 WebMChunkContext *wc = s->priv_data;
139 if (!filename) {
140 return AVERROR(EINVAL);
141 }
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);
146 }
147 return 0;
148 }
149
webm_chunk_write_header(AVFormatContext * s)150 static int webm_chunk_write_header(AVFormatContext *s)
151 {
152 WebMChunkContext *wc = s->priv_data;
153 AVFormatContext *oc = wc->avf;
154 int ret;
155
156 ret = avformat_write_header(oc, NULL);
157 ff_format_io_close(s, &oc->pb);
158 wc->header_written = 1;
159 if (ret < 0)
160 return ret;
161 return 0;
162 }
163
chunk_start(AVFormatContext * s)164 static int chunk_start(AVFormatContext *s)
165 {
166 WebMChunkContext *wc = s->priv_data;
167 AVFormatContext *oc = wc->avf;
168 int ret;
169
170 ret = avio_open_dyn_buf(&oc->pb);
171 if (ret < 0)
172 return ret;
173 wc->chunk_index++;
174 return 0;
175 }
176
chunk_end(AVFormatContext * s,int flush)177 static int chunk_end(AVFormatContext *s, int flush)
178 {
179 WebMChunkContext *wc = s->priv_data;
180 AVFormatContext *oc = wc->avf;
181 int ret;
182 int buffer_size;
183 uint8_t *buffer;
184 AVIOContext *pb;
185 char filename[MAX_FILENAME_SIZE];
186 AVDictionary *options = NULL;
187
188 if (!oc->pb)
189 return 0;
190
191 if (flush)
192 // Flush the cluster in WebM muxer.
193 av_write_frame(oc, NULL);
194 buffer_size = avio_close_dyn_buf(oc->pb, &buffer);
195 oc->pb = NULL;
196 ret = get_chunk_filename(s, filename);
197 if (ret < 0)
198 goto fail;
199 if (wc->http_method)
200 if ((ret = av_dict_set(&options, "method", wc->http_method, 0)) < 0)
201 goto fail;
202 ret = s->io_open(s, &pb, filename, AVIO_FLAG_WRITE, &options);
203 av_dict_free(&options);
204 if (ret < 0)
205 goto fail;
206 avio_write(pb, buffer, buffer_size);
207 ff_format_io_close(s, &pb);
208 fail:
209 av_free(buffer);
210 return (ret < 0) ? ret : 0;
211 }
212
webm_chunk_write_packet(AVFormatContext * s,AVPacket * pkt)213 static int webm_chunk_write_packet(AVFormatContext *s, AVPacket *pkt)
214 {
215 WebMChunkContext *wc = s->priv_data;
216 AVFormatContext *oc = wc->avf;
217 AVStream *st = s->streams[pkt->stream_index];
218 int ret;
219
220 if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
221 if (wc->prev_pts != AV_NOPTS_VALUE)
222 wc->duration_written += av_rescale_q(pkt->pts - wc->prev_pts,
223 st->time_base,
224 (AVRational) {1, 1000});
225 wc->prev_pts = pkt->pts;
226 }
227
228 // For video, a new chunk is started only on key frames. For audio, a new
229 // chunk is started based on chunk_duration. Also, a new chunk is started
230 // unconditionally if there is no currently open chunk.
231 if (!oc->pb || (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
232 (pkt->flags & AV_PKT_FLAG_KEY)) ||
233 (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
234 wc->duration_written >= wc->chunk_duration)) {
235 wc->duration_written = 0;
236 if ((ret = chunk_end(s, 1)) < 0 || (ret = chunk_start(s)) < 0) {
237 return ret;
238 }
239 }
240
241 // We only have one stream, so use the non-interleaving av_write_frame.
242 return av_write_frame(oc, pkt);
243 }
244
webm_chunk_write_trailer(AVFormatContext * s)245 static int webm_chunk_write_trailer(AVFormatContext *s)
246 {
247 WebMChunkContext *wc = s->priv_data;
248 AVFormatContext *oc = wc->avf;
249 int ret;
250
251 if (!oc->pb) {
252 ret = chunk_start(s);
253 if (ret < 0)
254 return ret;
255 }
256 ret = av_write_trailer(oc);
257 if (ret < 0)
258 return ret;
259 return chunk_end(s, 0);
260 }
261
webm_chunk_deinit(AVFormatContext * s)262 static void webm_chunk_deinit(AVFormatContext *s)
263 {
264 WebMChunkContext *wc = s->priv_data;
265
266 if (!wc->avf)
267 return;
268
269 if (wc->header_written)
270 ffio_free_dyn_buf(&wc->avf->pb);
271 else
272 ff_format_io_close(s, &wc->avf->pb);
273 avformat_free_context(wc->avf);
274 wc->avf = NULL;
275 }
276
277 #define OFFSET(x) offsetof(WebMChunkContext, x)
278 static const AVOption options[] = {
279 { "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 },
280 { "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 },
281 { "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 },
282 { "method", "set the HTTP method", OFFSET(http_method), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
283 { NULL },
284 };
285
286 static const AVClass webm_chunk_class = {
287 .class_name = "WebM Chunk Muxer",
288 .item_name = av_default_item_name,
289 .option = options,
290 .version = LIBAVUTIL_VERSION_INT,
291 };
292
293 const AVOutputFormat ff_webm_chunk_muxer = {
294 .name = "webm_chunk",
295 .long_name = NULL_IF_CONFIG_SMALL("WebM Chunk Muxer"),
296 .mime_type = "video/webm",
297 .extensions = "chk",
298 .flags = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NEEDNUMBER |
299 AVFMT_TS_NONSTRICT,
300 .priv_data_size = sizeof(WebMChunkContext),
301 .init = webm_chunk_init,
302 .write_header = webm_chunk_write_header,
303 .write_packet = webm_chunk_write_packet,
304 .write_trailer = webm_chunk_write_trailer,
305 .deinit = webm_chunk_deinit,
306 .priv_class = &webm_chunk_class,
307 };
308