text: /*
   * Ogg muxer
   * Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include "libavutil/crc.h"
  #include "libavutil/opt.h"
  #include "libavutil/mathematics.h"
  #include "libavutil/opt.h"
  #include "libavutil/random_seed.h"
  #include "libavcodec/xiph.h"
  #include "libavcodec/bytestream.h"
  #include "libavcodec/flac.h"
  #include "avformat.h"
  #include "avio_internal.h"
  #include "internal.h"
  #include "vorbiscomment.h"
  
  #define MAX_PAGE_SIZE 65025
  
  typedef struct {
      int64_t granule;
      int stream_index;
      uint8_t flags;
      uint8_t segments_count;
      uint8_t segments[255];
      uint8_t data[MAX_PAGE_SIZE];
      uint16_t size;
  } OGGPage;
  
  typedef struct {
      unsigned page_counter;
      uint8_t *header[3];
      int header_len[3];
      /** for theora granule */
      int kfgshift;
      int64_t last_kf_pts;
      int vrev;
      int eos;
      unsigned page_count; ///< number of page buffered
      OGGPage page; ///< current page
      unsigned serial_num; ///< serial number
      int64_t last_granule; ///< last packet granule
  } OGGStreamContext;
  
  typedef struct OGGPageList {
      OGGPage page;
      struct OGGPageList *next;
  } OGGPageList;
  
  typedef struct {
      const AVClass *class;
      OGGPageList *page_list;
      int pref_size; ///< preferred page size (0 => fill all segments)
  } OGGContext;
  
  #define OFFSET(x) offsetof(OGGContext, x)
  #define PARAM AV_OPT_FLAG_ENCODING_PARAM
  
  static const AVOption options[] = {
      { "oggpagesize", "Set preferred Ogg page size.",
        offsetof(OGGContext, pref_size), AV_OPT_TYPE_INT, {.dbl = 0}, 0, MAX_PAGE_SIZE, AV_OPT_FLAG_ENCODING_PARAM},
      { "pagesize", "preferred page size in bytes",
          OFFSET(pref_size), AV_OPT_TYPE_INT, { 0 }, 0, MAX_PAGE_SIZE, PARAM },
      { NULL },
  };
  
  static const AVClass ogg_muxer_class = {
      .class_name = "Ogg muxer",
      .item_name  = av_default_item_name,
      .option     = options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  
  static void ogg_update_checksum(AVFormatContext *s, AVIOContext *pb, int64_t crc_offset)
  {
      int64_t pos = avio_tell(pb);
      uint32_t checksum = ffio_get_checksum(pb);
      avio_seek(pb, crc_offset, SEEK_SET);
      avio_wb32(pb, checksum);
      avio_seek(pb, pos, SEEK_SET);
  }
  
  static int ogg_write_page(AVFormatContext *s, OGGPage *page, int extra_flags)
  {
      OGGStreamContext *oggstream = s->streams[page->stream_index]->priv_data;
      AVIOContext *pb;
      int64_t crc_offset;
      int ret, size;
      uint8_t *buf;
  
      ret = avio_open_dyn_buf(&pb);
      if (ret < 0)
          return ret;
      ffio_init_checksum(pb, ff_crc04C11DB7_update, 0);
      ffio_wfourcc(pb, "OggS");
      avio_w8(pb, 0);
      avio_w8(pb, page->flags | extra_flags);
      avio_wl64(pb, page->granule);
      avio_wl32(pb, oggstream->serial_num);
      avio_wl32(pb, oggstream->page_counter++);
      crc_offset = avio_tell(pb);
      avio_wl32(pb, 0); // crc
      avio_w8(pb, page->segments_count);
      avio_write(pb, page->segments, page->segments_count);
      avio_write(pb, page->data, page->size);
  
      ogg_update_checksum(s, pb, crc_offset);
      avio_flush(pb);
  
      size = avio_close_dyn_buf(pb, &buf);
      if (size < 0)
          return size;
  
      avio_write(s->pb, buf, size);
      avio_flush(s->pb);
      av_free(buf);
      oggstream->page_count--;
      return 0;
  }
  
  static int ogg_key_granule(OGGStreamContext *oggstream, int64_t granule)
  {
      return oggstream->kfgshift && !(granule & ((1<<oggstream->kfgshift)-1));
  }
  
  static int64_t ogg_granule_to_timestamp(OGGStreamContext *oggstream, int64_t granule)
  {
      if (oggstream->kfgshift)
          return (granule>>oggstream->kfgshift) +
              (granule & ((1<<oggstream->kfgshift)-1));
      else
          return granule;
  }
  
  static int ogg_compare_granule(AVFormatContext *s, OGGPage *next, OGGPage *page)
  {
      AVStream *st2 = s->streams[next->stream_index];
      AVStream *st  = s->streams[page->stream_index];
      int64_t next_granule, cur_granule;
  
      if (next->granule == -1 || page->granule == -1)
          return 0;
  
      next_granule = av_rescale_q(ogg_granule_to_timestamp(st2->priv_data, next->granule),
                                  st2->time_base, AV_TIME_BASE_Q);
      cur_granule  = av_rescale_q(ogg_granule_to_timestamp(st->priv_data, page->granule),
                                  st ->time_base, AV_TIME_BASE_Q);
      return next_granule > cur_granule;
  }
  
  static int ogg_reset_cur_page(OGGStreamContext *oggstream)
  {
      oggstream->page.granule = -1;
      oggstream->page.flags = 0;
      oggstream->page.segments_count = 0;
      oggstream->page.size = 0;
      return 0;
  }
  
  static int ogg_buffer_page(AVFormatContext *s, OGGStreamContext *oggstream)
  {
      OGGContext *ogg = s->priv_data;
      OGGPageList **p = &ogg->page_list;
      OGGPageList *l = av_mallocz(sizeof(*l));
  
      if (!l)
          return AVERROR(ENOMEM);
      l->page = oggstream->page;
  
      oggstream->page_count++;
      ogg_reset_cur_page(oggstream);
  
      while (*p) {
          if (ogg_compare_granule(s, &(*p)->page, &l->page))
              break;
          p = &(*p)->next;
      }
      l->next = *p;
      *p = l;
  
      return 0;
  }
  
  static int ogg_buffer_data(AVFormatContext *s, AVStream *st,
                             uint8_t *data, unsigned size, int64_t granule,
                             int header)
  {
      OGGStreamContext *oggstream = st->priv_data;
      OGGContext *ogg = s->priv_data;
      int total_segments = size / 255 + 1;
      uint8_t *p = data;
      int i, segments, len, flush = 0;
  
      // Handles VFR by flushing page because this frame needs to have a timestamp
      // For theora, keyframes also need to have a timestamp to correctly mark
      // them as such, otherwise seeking will not work correctly at the very
      // least with old libogg versions.
      // Do not try to flush header packets though, that will create broken files.
      if (st->codec->codec_id == CODEC_ID_THEORA && !header &&
          (ogg_granule_to_timestamp(oggstream, granule) >
           ogg_granule_to_timestamp(oggstream, oggstream->last_granule) + 1 ||
           ogg_key_granule(oggstream, granule))) {
          if (oggstream->page.granule != -1)
              ogg_buffer_page(s, oggstream);
          flush = 1;
      }
  
      for (i = 0; i < total_segments; ) {
          OGGPage *page = &oggstream->page;
  
          segments = FFMIN(total_segments - i, 255 - page->segments_count);
  
          if (i && !page->segments_count)
              page->flags |= 1; // continued packet
  
          memset(page->segments+page->segments_count, 255, segments - 1);
          page->segments_count += segments - 1;
  
          len = FFMIN(size, segments*255);
          page->segments[page->segments_count++] = len - (segments-1)*255;
          memcpy(page->data+page->size, p, len);
          p += len;
          size -= len;
          i += segments;
          page->size += len;
  
          if (i == total_segments)
              page->granule = granule;
  
          if (!header && (page->segments_count == 255 ||
              (ogg->pref_size > 0 && page->size >= ogg->pref_size))) {
             ogg_buffer_page(s, oggstream);
          }
      }
  
      if (flush && oggstream->page.granule != -1)
          ogg_buffer_page(s, oggstream);
  
      return 0;
  }
  
  static uint8_t *ogg_write_vorbiscomment(int offset, int bitexact,
                                          int *header_len, AVDictionary **m, int framing_bit)
  {
      const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
      int size;
      uint8_t *p, *p0;
      unsigned int count;
  
      ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
  
      size = offset + ff_vorbiscomment_length(*m, vendor, &count) + framing_bit;
      p = av_mallocz(size);
      if (!p)
          return NULL;
      p0 = p;
  
      p += offset;
      ff_vorbiscomment_write(&p, m, vendor, count);
      if (framing_bit)
          bytestream_put_byte(&p, 1);
  
      *header_len = size;
      return p0;
  }
  
  static int ogg_build_flac_headers(AVCodecContext *avctx,
                                    OGGStreamContext *oggstream, int bitexact,
                                    AVDictionary **m)
  {
      enum FLACExtradataFormat format;
      uint8_t *streaminfo;
      uint8_t *p;
  
      if (!avpriv_flac_is_extradata_valid(avctx, &format, &streaminfo))
          return -1;
  
      // first packet: STREAMINFO
      oggstream->header_len[0] = 51;
      oggstream->header[0] = av_mallocz(51); // per ogg flac specs
      p = oggstream->header[0];
      if (!p)
          return AVERROR(ENOMEM);
      bytestream_put_byte(&p, 0x7F);
      bytestream_put_buffer(&p, "FLAC", 4);
      bytestream_put_byte(&p, 1); // major version
      bytestream_put_byte(&p, 0); // minor version
      bytestream_put_be16(&p, 1); // headers packets without this one
      bytestream_put_buffer(&p, "fLaC", 4);
      bytestream_put_byte(&p, 0x00); // streaminfo
      bytestream_put_be24(&p, 34);
      bytestream_put_buffer(&p, streaminfo, FLAC_STREAMINFO_SIZE);
  
      // second packet: VorbisComment
      p = ogg_write_vorbiscomment(4, bitexact, &oggstream->header_len[1], m, 0);
      if (!p)
          return AVERROR(ENOMEM);
      oggstream->header[1] = p;
      bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment
      bytestream_put_be24(&p, oggstream->header_len[1] - 4);
  
      return 0;
  }
  
  #define SPEEX_HEADER_SIZE 80
  
  static int ogg_build_speex_headers(AVCodecContext *avctx,
                                     OGGStreamContext *oggstream, int bitexact,
                                     AVDictionary **m)
  {
      uint8_t *p;
  
      if (avctx->extradata_size < SPEEX_HEADER_SIZE)
          return -1;
  
      // first packet: Speex header
      p = av_mallocz(SPEEX_HEADER_SIZE);
      if (!p)
          return AVERROR(ENOMEM);
      oggstream->header[0] = p;
      oggstream->header_len[0] = SPEEX_HEADER_SIZE;
      bytestream_put_buffer(&p, avctx->extradata, SPEEX_HEADER_SIZE);
      AV_WL32(&oggstream->header[0][68], 0);  // set extra_headers to 0
  
      // second packet: VorbisComment
      p = ogg_write_vorbiscomment(0, bitexact, &oggstream->header_len[1], m, 0);
      if (!p)
          return AVERROR(ENOMEM);
      oggstream->header[1] = p;
  
      return 0;
  }
  
  static int ogg_write_header(AVFormatContext *s)
  {
      OGGStreamContext *oggstream;
      int i, j;
  
      for (i = 0; i < s->nb_streams; i++) {
          AVStream *st = s->streams[i];
          unsigned serial_num = i;
  
          if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
              avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
          else if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
              avpriv_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);
          if (st->codec->codec_id != CODEC_ID_VORBIS &&
              st->codec->codec_id != CODEC_ID_THEORA &&
              st->codec->codec_id != CODEC_ID_SPEEX  &&
              st->codec->codec_id != CODEC_ID_FLAC) {
              av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
              return -1;
          }
  
          if (!st->codec->extradata || !st->codec->extradata_size) {
              av_log(s, AV_LOG_ERROR, "No extradata present\n");
              return -1;
          }
          oggstream = av_mallocz(sizeof(*oggstream));
          oggstream->page.stream_index = i;
  
          if (!(st->codec->flags & CODEC_FLAG_BITEXACT))
              do {
                  serial_num = av_get_random_seed();
                  for (j = 0; j < i; j++) {
                      OGGStreamContext *sc = s->streams[j]->priv_data;
                      if (serial_num == sc->serial_num)
                          break;
                  }
              } while (j < i);
          oggstream->serial_num = serial_num;
  
          st->priv_data = oggstream;
          if (st->codec->codec_id == CODEC_ID_FLAC) {
              int err = ogg_build_flac_headers(st->codec, oggstream,
                                               st->codec->flags & CODEC_FLAG_BITEXACT,
                                               &s->metadata);
              if (err) {
                  av_log(s, AV_LOG_ERROR, "Error writing FLAC headers\n");
                  av_freep(&st->priv_data);
                  return err;
              }
          } else if (st->codec->codec_id == CODEC_ID_SPEEX) {
              int err = ogg_build_speex_headers(st->codec, oggstream,
                                                st->codec->flags & CODEC_FLAG_BITEXACT,
                                                &s->metadata);
              if (err) {
                  av_log(s, AV_LOG_ERROR, "Error writing Speex headers\n");
                  av_freep(&st->priv_data);
                  return err;
              }
          } else {
              uint8_t *p;
              const char *cstr = st->codec->codec_id == CODEC_ID_VORBIS ? "vorbis" : "theora";
              int header_type = st->codec->codec_id == CODEC_ID_VORBIS ? 3 : 0x81;
              int framing_bit = st->codec->codec_id == CODEC_ID_VORBIS ? 1 : 0;
  
              if (avpriv_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
                                        st->codec->codec_id == CODEC_ID_VORBIS ? 30 : 42,
                                        oggstream->header, oggstream->header_len) < 0) {
                  av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
                  av_freep(&st->priv_data);
                  return -1;
              }
  
              p = ogg_write_vorbiscomment(7, st->codec->flags & CODEC_FLAG_BITEXACT,
                                          &oggstream->header_len[1], &s->metadata,
                                          framing_bit);
              oggstream->header[1] = p;
              if (!p)
                  return AVERROR(ENOMEM);
  
              bytestream_put_byte(&p, header_type);
              bytestream_put_buffer(&p, cstr, 6);
  
              if (st->codec->codec_id == CODEC_ID_THEORA) {
                  /** KFGSHIFT is the width of the less significant section of the granule position
                      The less significant section is the frame count since the last keyframe */
                  oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
                  oggstream->vrev = oggstream->header[0][9];
                  av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",
                         oggstream->kfgshift, oggstream->vrev);
              }
          }
      }
  
      for (j = 0; j < s->nb_streams; j++) {
          OGGStreamContext *oggstream = s->streams[j]->priv_data;
          ogg_buffer_data(s, s->streams[j], oggstream->header[0],
                          oggstream->header_len[0], 0, 1);
          oggstream->page.flags |= 2; // bos
          ogg_buffer_page(s, oggstream);
      }
      for (j = 0; j < s->nb_streams; j++) {
          AVStream *st = s->streams[j];
          OGGStreamContext *oggstream = st->priv_data;
          for (i = 1; i < 3; i++) {
              if (oggstream && oggstream->header_len[i])
                  ogg_buffer_data(s, st, oggstream->header[i],
                                  oggstream->header_len[i], 0, 1);
          }
          ogg_buffer_page(s, oggstream);
      }
      return 0;
  }
  
  static void ogg_write_pages(AVFormatContext *s, int flush)
  {
      OGGContext *ogg = s->priv_data;
      OGGPageList *next, *p;
  
      if (!ogg->page_list)
          return;
  
      for (p = ogg->page_list; p; ) {
          OGGStreamContext *oggstream =
              s->streams[p->page.stream_index]->priv_data;
          if (oggstream->page_count < 2 && !flush)
              break;
          ogg_write_page(s, &p->page,
                         flush && oggstream->page_count == 1 ? 4 : 0); // eos
          next = p->next;
          av_freep(&p);
          p = next;
      }
      ogg->page_list = p;
  }
  
  static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
  {
      AVStream *st = s->streams[pkt->stream_index];
      OGGStreamContext *oggstream = st->priv_data;
      int ret;
      int64_t granule;
  
      if (st->codec->codec_id == CODEC_ID_THEORA) {
          int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
          int pframe_count;
          if (pkt->flags & AV_PKT_FLAG_KEY)
              oggstream->last_kf_pts = pts;
          pframe_count = pts - oggstream->last_kf_pts;
          // prevent frame count from overflow if key frame flag is not set
          if (pframe_count >= (1<<oggstream->kfgshift)) {
              oggstream->last_kf_pts += pframe_count;
              pframe_count = 0;
          }
          granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
      } else
          granule = pkt->pts + pkt->duration;
  
      ret = ogg_buffer_data(s, st, pkt->data, pkt->size, granule, 0);
      if (ret < 0)
          return ret;
  
      ogg_write_pages(s, 0);
  
      oggstream->last_granule = granule;
  
      return 0;
  }
  
  static int ogg_write_trailer(AVFormatContext *s)
  {
      int i;
  
      /* flush current page */
      for (i = 0; i < s->nb_streams; i++)
          ogg_buffer_page(s, s->streams[i]->priv_data);
  
      ogg_write_pages(s, 1);
  
      for (i = 0; i < s->nb_streams; i++) {
          AVStream *st = s->streams[i];
          OGGStreamContext *oggstream = st->priv_data;
          if (st->codec->codec_id == CODEC_ID_FLAC ||
              st->codec->codec_id == CODEC_ID_SPEEX) {
              av_freep(&oggstream->header[0]);
          }
          av_freep(&oggstream->header[1]);
          av_freep(&st->priv_data);
      }
      return 0;
  }
  
  AVOutputFormat ff_ogg_muxer = {
      .name              = "ogg",
      .long_name         = NULL_IF_CONFIG_SMALL("Ogg"),
      .mime_type         = "application/ogg",
      .extensions        = "ogg,ogv,spx",
      .priv_data_size    = sizeof(OGGContext),
      .audio_codec       = CODEC_ID_FLAC,
      .video_codec       = CODEC_ID_THEORA,
      .write_header      = ogg_write_header,
      .write_packet      = ogg_write_packet,
      .write_trailer     = ogg_write_trailer,
      .priv_class        = &ogg_muxer_class,
  };
  