git.sesse.net Git - ffmpeg/blob - libavformat/oggenc.c

   1 /*
   2  * Ogg muxer
   3  * Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <stdint.h>
  23
  24 #include "libavutil/crc.h"
  25 #include "libavutil/mathematics.h"
  26 #include "libavutil/opt.h"
  27 #include "libavutil/random_seed.h"
  28 #include "libavcodec/xiph.h"
  29 #include "libavcodec/bytestream.h"
  30 #include "libavcodec/flac.h"
  31 #include "avformat.h"
  32 #include "avio_internal.h"
  33 #include "internal.h"
  34 #include "vorbiscomment.h"
  35
  36 #define MAX_PAGE_SIZE 65025
  37
  38 typedef struct {
  39     int64_t start_granule;
  40     int64_t granule;
  41     int stream_index;
  42     uint8_t flags;
  43     uint8_t segments_count;
  44     uint8_t segments[255];
  45     uint8_t data[MAX_PAGE_SIZE];
  46     uint16_t size;
  47 } OGGPage;
  48
  49 typedef struct {
  50     unsigned page_counter;
  51     uint8_t *header[3];
  52     int header_len[3];
  53     /** for theora granule */
  54     int kfgshift;
  55     int64_t last_kf_pts;
  56     int vrev;
  57     int eos;
  58     unsigned page_count; ///< number of page buffered
  59     OGGPage page; ///< current page
  60     unsigned serial_num; ///< serial number
  61     int64_t last_granule; ///< last packet granule
  62 } OGGStreamContext;
  63
  64 typedef struct OGGPageList {
  65     OGGPage page;
  66     struct OGGPageList *next;
  67 } OGGPageList;
  68
  69 typedef struct {
  70     const AVClass *class;
  71     OGGPageList *page_list;
  72     int pref_size; ///< preferred page size (0 => fill all segments)
  73     int64_t pref_duration;      ///< preferred page duration (0 => fill all segments)
  74 } OGGContext;
  75
  76 #define OFFSET(x) offsetof(OGGContext, x)
  77 #define PARAM AV_OPT_FLAG_ENCODING_PARAM
  78
  79 static const AVOption options[] = {
  80     { "pagesize", "preferred page size in bytes (deprecated)",
  81         OFFSET(pref_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, MAX_PAGE_SIZE, PARAM },
  82     { "page_duration", "preferred page duration, in microseconds",
  83         OFFSET(pref_duration), AV_OPT_TYPE_INT64, { .i64 = 1000000 }, 0, INT64_MAX, PARAM },
  84     { NULL },
  85 };
  86
  87 static const AVClass ogg_muxer_class = {
  88     .class_name = "Ogg muxer",
  89     .item_name  = av_default_item_name,
  90     .option     = options,
  91     .version    = LIBAVUTIL_VERSION_INT,
  92 };
  93
  94
  95 static void ogg_update_checksum(AVFormatContext *s, AVIOContext *pb, int64_t crc_offset)
  96 {
  97     int64_t pos = avio_tell(pb);
  98     uint32_t checksum = ffio_get_checksum(pb);
  99     avio_seek(pb, crc_offset, SEEK_SET);
 100     avio_wb32(pb, checksum);
 101     avio_seek(pb, pos, SEEK_SET);
 102 }
 103
 104 static int ogg_write_page(AVFormatContext *s, OGGPage *page, int extra_flags)
 105 {
 106     OGGStreamContext *oggstream = s->streams[page->stream_index]->priv_data;
 107     AVIOContext *pb;
 108     int64_t crc_offset;
 109     int ret, size;
 110     uint8_t *buf;
 111
 112     ret = avio_open_dyn_buf(&pb);
 113     if (ret < 0)
 114         return ret;
 115     ffio_init_checksum(pb, ff_crc04C11DB7_update, 0);
 116     ffio_wfourcc(pb, "OggS");
 117     avio_w8(pb, 0);
 118     avio_w8(pb, page->flags | extra_flags);
 119     avio_wl64(pb, page->granule);
 120     avio_wl32(pb, oggstream->serial_num);
 121     avio_wl32(pb, oggstream->page_counter++);
 122     crc_offset = avio_tell(pb);
 123     avio_wl32(pb, 0); // crc
 124     avio_w8(pb, page->segments_count);
 125     avio_write(pb, page->segments, page->segments_count);
 126     avio_write(pb, page->data, page->size);
 127
 128     ogg_update_checksum(s, pb, crc_offset);
 129     avio_flush(pb);
 130
 131     size = avio_close_dyn_buf(pb, &buf);
 132     if (size < 0)
 133         return size;
 134
 135     avio_write(s->pb, buf, size);
 136     avio_flush(s->pb);
 137     av_free(buf);
 138     oggstream->page_count--;
 139     return 0;
 140 }
 141
 142 static int64_t ogg_granule_to_timestamp(OGGStreamContext *oggstream, int64_t granule)
 143 {
 144     if (oggstream->kfgshift)
 145         return (granule>>oggstream->kfgshift) +
 146             (granule & ((1<<oggstream->kfgshift)-1));
 147     else
 148         return granule;
 149 }
 150
 151 static int ogg_compare_granule(AVFormatContext *s, OGGPage *next, OGGPage *page)
 152 {
 153     AVStream *st2 = s->streams[next->stream_index];
 154     AVStream *st  = s->streams[page->stream_index];
 155     int64_t next_granule, cur_granule;
 156
 157     if (next->granule == -1 || page->granule == -1)
 158         return 0;
 159
 160     next_granule = av_rescale_q(ogg_granule_to_timestamp(st2->priv_data, next->granule),
 161                                 st2->time_base, AV_TIME_BASE_Q);
 162     cur_granule  = av_rescale_q(ogg_granule_to_timestamp(st->priv_data, page->granule),
 163                                 st ->time_base, AV_TIME_BASE_Q);
 164     return next_granule > cur_granule;
 165 }
 166
 167 static int ogg_reset_cur_page(OGGStreamContext *oggstream)
 168 {
 169     oggstream->page.granule = -1;
 170     oggstream->page.flags = 0;
 171     oggstream->page.segments_count = 0;
 172     oggstream->page.size = 0;
 173     return 0;
 174 }
 175
 176 static int ogg_buffer_page(AVFormatContext *s, OGGStreamContext *oggstream)
 177 {
 178     OGGContext *ogg = s->priv_data;
 179     OGGPageList **p = &ogg->page_list;
 180     OGGPageList *l = av_mallocz(sizeof(*l));
 181
 182     if (!l)
 183         return AVERROR(ENOMEM);
 184     l->page = oggstream->page;
 185
 186     oggstream->page.start_granule = oggstream->page.granule;
 187     oggstream->page_count++;
 188     ogg_reset_cur_page(oggstream);
 189
 190     while (*p) {
 191         if (ogg_compare_granule(s, &(*p)->page, &l->page))
 192             break;
 193         p = &(*p)->next;
 194     }
 195     l->next = *p;
 196     *p = l;
 197
 198     return 0;
 199 }
 200
 201 static int ogg_buffer_data(AVFormatContext *s, AVStream *st,
 202                            uint8_t *data, unsigned size, int64_t granule,
 203                            int header)
 204 {
 205     OGGStreamContext *oggstream = st->priv_data;
 206     OGGContext *ogg = s->priv_data;
 207     int total_segments = size / 255 + 1;
 208     uint8_t *p = data;
 209     int i, segments, len, flush = 0;
 210
 211     // Handles VFR by flushing page because this frame needs to have a timestamp
 212     if (st->codec->codec_id == AV_CODEC_ID_THEORA && !header &&
 213         ogg_granule_to_timestamp(oggstream, granule) >
 214         ogg_granule_to_timestamp(oggstream, oggstream->last_granule) + 1) {
 215         if (oggstream->page.granule != -1)
 216             ogg_buffer_page(s, oggstream);
 217         flush = 1;
 218     }
 219
 220     // avoid a continued page
 221     if (!header && oggstream->page.size > 0 &&
 222         MAX_PAGE_SIZE - oggstream->page.size < size) {
 223         ogg_buffer_page(s, oggstream);
 224     }
 225
 226     for (i = 0; i < total_segments; ) {
 227         OGGPage *page = &oggstream->page;
 228
 229         segments = FFMIN(total_segments - i, 255 - page->segments_count);
 230
 231         if (i && !page->segments_count)
 232             page->flags |= 1; // continued packet
 233
 234         memset(page->segments+page->segments_count, 255, segments - 1);
 235         page->segments_count += segments - 1;
 236
 237         len = FFMIN(size, segments*255);
 238         page->segments[page->segments_count++] = len - (segments-1)*255;
 239         memcpy(page->data+page->size, p, len);
 240         p += len;
 241         size -= len;
 242         i += segments;
 243         page->size += len;
 244
 245         if (i == total_segments)
 246             page->granule = granule;
 247
 248         if (!header) {
 249             AVStream *st = s->streams[page->stream_index];
 250
 251             int64_t start = av_rescale_q(page->start_granule, st->time_base,
 252                                          AV_TIME_BASE_Q);
 253             int64_t next  = av_rescale_q(page->granule, st->time_base,
 254                                          AV_TIME_BASE_Q);
 255
 256             if (page->segments_count == 255 ||
 257                 (ogg->pref_size     > 0 && page->size   >= ogg->pref_size) ||
 258                 (ogg->pref_duration > 0 && next - start >= ogg->pref_duration)) {
 259                 ogg_buffer_page(s, oggstream);
 260             }
 261         }
 262     }
 263
 264     if (flush && oggstream->page.granule != -1)
 265         ogg_buffer_page(s, oggstream);
 266
 267     return 0;
 268 }
 269
 270 static uint8_t *ogg_write_vorbiscomment(int offset, int bitexact,
 271                                         int *header_len, AVDictionary **m, int framing_bit)
 272 {
 273     const char *vendor = bitexact ? "Libav" : LIBAVFORMAT_IDENT;
 274     int size;
 275     uint8_t *p, *p0;
 276
 277     ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
 278
 279     size = offset + ff_vorbiscomment_length(*m, vendor) + framing_bit;
 280     p = av_mallocz(size);
 281     if (!p)
 282         return NULL;
 283     p0 = p;
 284
 285     p += offset;
 286     ff_vorbiscomment_write(&p, m, vendor);
 287     if (framing_bit)
 288         bytestream_put_byte(&p, 1);
 289
 290     *header_len = size;
 291     return p0;
 292 }
 293
 294 static int ogg_build_flac_headers(AVCodecContext *avctx,
 295                                   OGGStreamContext *oggstream, int bitexact,
 296                                   AVDictionary **m)
 297 {
 298     enum FLACExtradataFormat format;
 299     uint8_t *streaminfo;
 300     uint8_t *p;
 301
 302     if (!avpriv_flac_is_extradata_valid(avctx, &format, &streaminfo))
 303         return -1;
 304
 305     // first packet: STREAMINFO
 306     oggstream->header_len[0] = 51;
 307     oggstream->header[0] = av_mallocz(51); // per ogg flac specs
 308     p = oggstream->header[0];
 309     if (!p)
 310         return AVERROR(ENOMEM);
 311     bytestream_put_byte(&p, 0x7F);
 312     bytestream_put_buffer(&p, "FLAC", 4);
 313     bytestream_put_byte(&p, 1); // major version
 314     bytestream_put_byte(&p, 0); // minor version
 315     bytestream_put_be16(&p, 1); // headers packets without this one
 316     bytestream_put_buffer(&p, "fLaC", 4);
 317     bytestream_put_byte(&p, 0x00); // streaminfo
 318     bytestream_put_be24(&p, 34);
 319     bytestream_put_buffer(&p, streaminfo, FLAC_STREAMINFO_SIZE);
 320
 321     // second packet: VorbisComment
 322     p = ogg_write_vorbiscomment(4, bitexact, &oggstream->header_len[1], m, 0);
 323     if (!p)
 324         return AVERROR(ENOMEM);
 325     oggstream->header[1] = p;
 326     bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment
 327     bytestream_put_be24(&p, oggstream->header_len[1] - 4);
 328
 329     return 0;
 330 }
 331
 332 #define SPEEX_HEADER_SIZE 80
 333
 334 static int ogg_build_speex_headers(AVCodecContext *avctx,
 335                                    OGGStreamContext *oggstream, int bitexact,
 336                                    AVDictionary **m)
 337 {
 338     uint8_t *p;
 339
 340     if (avctx->extradata_size < SPEEX_HEADER_SIZE)
 341         return -1;
 342
 343     // first packet: Speex header
 344     p = av_mallocz(SPEEX_HEADER_SIZE);
 345     if (!p)
 346         return AVERROR(ENOMEM);
 347     oggstream->header[0] = p;
 348     oggstream->header_len[0] = SPEEX_HEADER_SIZE;
 349     bytestream_put_buffer(&p, avctx->extradata, SPEEX_HEADER_SIZE);
 350     AV_WL32(&oggstream->header[0][68], 0);  // set extra_headers to 0
 351
 352     // second packet: VorbisComment
 353     p = ogg_write_vorbiscomment(0, bitexact, &oggstream->header_len[1], m, 0);
 354     if (!p)
 355         return AVERROR(ENOMEM);
 356     oggstream->header[1] = p;
 357
 358     return 0;
 359 }
 360
 361 #define OPUS_HEADER_SIZE 19
 362
 363 static int ogg_build_opus_headers(AVCodecContext *avctx,
 364                                   OGGStreamContext *oggstream, int bitexact,
 365                                   AVDictionary **m)
 366 {
 367     uint8_t *p;
 368
 369     if (avctx->extradata_size < OPUS_HEADER_SIZE)
 370         return -1;
 371
 372     /* first packet: Opus header */
 373     p = av_mallocz(avctx->extradata_size);
 374     if (!p)
 375         return AVERROR(ENOMEM);
 376     oggstream->header[0] = p;
 377     oggstream->header_len[0] = avctx->extradata_size;
 378     bytestream_put_buffer(&p, avctx->extradata, avctx->extradata_size);
 379
 380     /* second packet: VorbisComment */
 381     p = ogg_write_vorbiscomment(8, bitexact, &oggstream->header_len[1], m, 0);
 382     if (!p)
 383         return AVERROR(ENOMEM);
 384     oggstream->header[1] = p;
 385     bytestream_put_buffer(&p, "OpusTags", 8);
 386
 387     return 0;
 388 }
 389
 390 static void ogg_write_pages(AVFormatContext *s, int flush)
 391 {
 392     OGGContext *ogg = s->priv_data;
 393     OGGPageList *next, *p;
 394
 395     if (!ogg->page_list)
 396         return;
 397
 398     for (p = ogg->page_list; p; ) {
 399         OGGStreamContext *oggstream =
 400             s->streams[p->page.stream_index]->priv_data;
 401         if (oggstream->page_count < 2 && !flush)
 402             break;
 403         ogg_write_page(s, &p->page,
 404                        flush == 1 && oggstream->page_count == 1 ? 4 : 0); // eos
 405         next = p->next;
 406         av_freep(&p);
 407         p = next;
 408     }
 409     ogg->page_list = p;
 410 }
 411
 412 static int ogg_write_header(AVFormatContext *s)
 413 {
 414     OGGContext *ogg = s->priv_data;
 415     OGGStreamContext *oggstream;
 416     int i, j;
 417
 418     if (ogg->pref_size)
 419         av_log(s, AV_LOG_WARNING, "The pagesize option is deprecated\n");
 420
 421     for (i = 0; i < s->nb_streams; i++) {
 422         AVStream *st = s->streams[i];
 423         unsigned serial_num = i;
 424
 425         if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
 426             if (st->codec->codec_id == AV_CODEC_ID_OPUS)
 427                 /* Opus requires a fixed 48kHz clock */
 428                 avpriv_set_pts_info(st, 64, 1, 48000);
 429             else
 430                 avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
 431         else if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
 432             avpriv_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);
 433         if (st->codec->codec_id != AV_CODEC_ID_VORBIS &&
 434             st->codec->codec_id != AV_CODEC_ID_THEORA &&
 435             st->codec->codec_id != AV_CODEC_ID_SPEEX  &&
 436             st->codec->codec_id != AV_CODEC_ID_FLAC   &&
 437             st->codec->codec_id != AV_CODEC_ID_OPUS) {
 438             av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
 439             return -1;
 440         }
 441
 442         if (!st->codec->extradata || !st->codec->extradata_size) {
 443             av_log(s, AV_LOG_ERROR, "No extradata present\n");
 444             return -1;
 445         }
 446         oggstream = av_mallocz(sizeof(*oggstream));
 447         oggstream->page.stream_index = i;
 448
 449         if (!(s->flags & AVFMT_FLAG_BITEXACT))
 450             do {
 451                 serial_num = av_get_random_seed();
 452                 for (j = 0; j < i; j++) {
 453                     OGGStreamContext *sc = s->streams[j]->priv_data;
 454                     if (serial_num == sc->serial_num)
 455                         break;
 456                 }
 457             } while (j < i);
 458         oggstream->serial_num = serial_num;
 459
 460         st->priv_data = oggstream;
 461         if (st->codec->codec_id == AV_CODEC_ID_FLAC) {
 462             int err = ogg_build_flac_headers(st->codec, oggstream,
 463                                              s->flags & AVFMT_FLAG_BITEXACT,
 464                                              &s->metadata);
 465             if (err) {
 466                 av_log(s, AV_LOG_ERROR, "Error writing FLAC headers\n");
 467                 av_freep(&st->priv_data);
 468                 return err;
 469             }
 470         } else if (st->codec->codec_id == AV_CODEC_ID_SPEEX) {
 471             int err = ogg_build_speex_headers(st->codec, oggstream,
 472                                               s->flags & AVFMT_FLAG_BITEXACT,
 473                                               &s->metadata);
 474             if (err) {
 475                 av_log(s, AV_LOG_ERROR, "Error writing Speex headers\n");
 476                 av_freep(&st->priv_data);
 477                 return err;
 478             }
 479         } else if (st->codec->codec_id == AV_CODEC_ID_OPUS) {
 480             int err = ogg_build_opus_headers(st->codec, oggstream,
 481                                              s->flags & AVFMT_FLAG_BITEXACT,
 482                                              &s->metadata);
 483             if (err) {
 484                 av_log(s, AV_LOG_ERROR, "Error writing Opus headers\n");
 485                 av_freep(&st->priv_data);
 486                 return err;
 487             }
 488         } else {
 489             uint8_t *p;
 490             const char *cstr = st->codec->codec_id == AV_CODEC_ID_VORBIS ? "vorbis" : "theora";
 491             int header_type = st->codec->codec_id == AV_CODEC_ID_VORBIS ? 3 : 0x81;
 492             int framing_bit = st->codec->codec_id == AV_CODEC_ID_VORBIS ? 1 : 0;
 493
 494             if (avpriv_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
 495                                       st->codec->codec_id == AV_CODEC_ID_VORBIS ? 30 : 42,
 496                                       oggstream->header, oggstream->header_len) < 0) {
 497                 av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
 498                 av_freep(&st->priv_data);
 499                 return -1;
 500             }
 501
 502             p = ogg_write_vorbiscomment(7, s->flags & AVFMT_FLAG_BITEXACT,
 503                                         &oggstream->header_len[1], &s->metadata,
 504                                         framing_bit);
 505             oggstream->header[1] = p;
 506             if (!p)
 507                 return AVERROR(ENOMEM);
 508
 509             bytestream_put_byte(&p, header_type);
 510             bytestream_put_buffer(&p, cstr, 6);
 511
 512             if (st->codec->codec_id == AV_CODEC_ID_THEORA) {
 513                 /** KFGSHIFT is the width of the less significant section of the granule position
 514                     The less significant section is the frame count since the last keyframe */
 515                 oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
 516                 oggstream->vrev = oggstream->header[0][9];
 517                 av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",
 518                        oggstream->kfgshift, oggstream->vrev);
 519             }
 520         }
 521     }
 522
 523     for (j = 0; j < s->nb_streams; j++) {
 524         OGGStreamContext *oggstream = s->streams[j]->priv_data;
 525         ogg_buffer_data(s, s->streams[j], oggstream->header[0],
 526                         oggstream->header_len[0], 0, 1);
 527         oggstream->page.flags |= 2; // bos
 528         ogg_buffer_page(s, oggstream);
 529     }
 530     for (j = 0; j < s->nb_streams; j++) {
 531         AVStream *st = s->streams[j];
 532         OGGStreamContext *oggstream = st->priv_data;
 533         for (i = 1; i < 3; i++) {
 534             if (oggstream && oggstream->header_len[i])
 535                 ogg_buffer_data(s, st, oggstream->header[i],
 536                                 oggstream->header_len[i], 0, 1);
 537         }
 538         ogg_buffer_page(s, oggstream);
 539     }
 540
 541     oggstream->page.start_granule = AV_NOPTS_VALUE;
 542
 543     ogg_write_pages(s, 2);
 544
 545     return 0;
 546 }
 547
 548 static int ogg_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
 549 {
 550     AVStream *st = s->streams[pkt->stream_index];
 551     OGGStreamContext *oggstream = st->priv_data;
 552     int ret;
 553     int64_t granule;
 554
 555     if (st->codec->codec_id == AV_CODEC_ID_THEORA) {
 556         int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
 557         int pframe_count;
 558         if (pkt->flags & AV_PKT_FLAG_KEY)
 559             oggstream->last_kf_pts = pts;
 560         pframe_count = pts - oggstream->last_kf_pts;
 561         // prevent frame count from overflow if key frame flag is not set
 562         if (pframe_count >= (1<<oggstream->kfgshift)) {
 563             oggstream->last_kf_pts += pframe_count;
 564             pframe_count = 0;
 565         }
 566         granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
 567     } else if (st->codec->codec_id == AV_CODEC_ID_OPUS)
 568         granule = pkt->pts + pkt->duration + av_rescale_q(st->codec->delay, (AVRational){ 1, st->codec->sample_rate }, st->time_base);
 569     else
 570         granule = pkt->pts + pkt->duration;
 571
 572     if (oggstream->page.start_granule == AV_NOPTS_VALUE)
 573         oggstream->page.start_granule = pkt->pts;
 574
 575     ret = ogg_buffer_data(s, st, pkt->data, pkt->size, granule, 0);
 576     if (ret < 0)
 577         return ret;
 578
 579     ogg_write_pages(s, 0);
 580
 581     oggstream->last_granule = granule;
 582
 583     return 0;
 584 }
 585
 586 static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
 587 {
 588     int i;
 589
 590     if (pkt)
 591         return ogg_write_packet_internal(s, pkt);
 592
 593     for (i = 0; i < s->nb_streams; i++) {
 594         OGGStreamContext *oggstream = s->streams[i]->priv_data;
 595         if (oggstream->page.segments_count)
 596             ogg_buffer_page(s, oggstream);
 597     }
 598
 599     ogg_write_pages(s, 2);
 600     return 0;
 601 }
 602
 603 static int ogg_write_trailer(AVFormatContext *s)
 604 {
 605     int i;
 606
 607     /* flush current page if needed */
 608     for (i = 0; i < s->nb_streams; i++) {
 609         OGGStreamContext *oggstream = s->streams[i]->priv_data;
 610
 611         if (oggstream->page.size > 0)
 612             ogg_buffer_page(s, oggstream);
 613     }
 614
 615     ogg_write_pages(s, 1);
 616
 617     for (i = 0; i < s->nb_streams; i++) {
 618         AVStream *st = s->streams[i];
 619         OGGStreamContext *oggstream = st->priv_data;
 620         if (st->codec->codec_id == AV_CODEC_ID_FLAC ||
 621             st->codec->codec_id == AV_CODEC_ID_SPEEX ||
 622             st->codec->codec_id == AV_CODEC_ID_OPUS) {
 623             av_free(oggstream->header[0]);
 624         }
 625         av_freep(&oggstream->header[1]);
 626         av_freep(&st->priv_data);
 627     }
 628     return 0;
 629 }
 630
 631 AVOutputFormat ff_ogg_muxer = {
 632     .name              = "ogg",
 633     .long_name         = NULL_IF_CONFIG_SMALL("Ogg"),
 634     .mime_type         = "application/ogg",
 635     .extensions        = "ogg,ogv,spx,opus",
 636     .priv_data_size    = sizeof(OGGContext),
 637     .audio_codec       = CONFIG_LIBVORBIS_ENCODER ?
 638                          AV_CODEC_ID_VORBIS : AV_CODEC_ID_FLAC,
 639     .video_codec       = AV_CODEC_ID_THEORA,
 640     .write_header      = ogg_write_header,
 641     .write_packet      = ogg_write_packet,
 642     .write_trailer     = ogg_write_trailer,
 643     .flags             = AVFMT_TS_NEGATIVE | AVFMT_ALLOW_FLUSH,
 644     .priv_class        = &ogg_muxer_class,
 645 };