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  1. /*
  2.  * Xiph CELT parser for Ogg
  3.  * Copyright (c) 2011 Nicolas George
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg 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.  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include <string.h>
  23.  
  24. #include "libavutil/intreadwrite.h"
  25. #include "avformat.h"
  26. #include "internal.h"
  27. #include "oggdec.h"
  28.  
  29. struct oggcelt_private {
  30.     int extra_headers_left;
  31. };
  32.  
  33. static int celt_header(AVFormatContext *s, int idx)
  34. {
  35.     struct ogg *ogg = s->priv_data;
  36.     struct ogg_stream *os = ogg->streams + idx;
  37.     AVStream *st = s->streams[idx];
  38.     struct oggcelt_private *priv = os->private;
  39.     uint8_t *p = os->buf + os->pstart;
  40.  
  41.     if (os->psize == 60 &&
  42.         !memcmp(p, ff_celt_codec.magic, ff_celt_codec.magicsize)) {
  43.         /* Main header */
  44.  
  45.         uint32_t version, sample_rate, nb_channels, frame_size;
  46.         uint32_t overlap, extra_headers;
  47.  
  48.         priv = av_malloc(sizeof(struct oggcelt_private));
  49.         if (!priv)
  50.             return AVERROR(ENOMEM);
  51.         if (ff_alloc_extradata(st->codec, 2 * sizeof(uint32_t)) < 0)
  52.             return AVERROR(ENOMEM);
  53.         version          = AV_RL32(p + 28);
  54.         /* unused header size field skipped */
  55.         sample_rate      = AV_RL32(p + 36);
  56.         nb_channels      = AV_RL32(p + 40);
  57.         frame_size       = AV_RL32(p + 44);
  58.         overlap          = AV_RL32(p + 48);
  59.         /* unused bytes per packet field skipped */
  60.         extra_headers    = AV_RL32(p + 56);
  61.         st->codec->codec_type     = AVMEDIA_TYPE_AUDIO;
  62.         st->codec->codec_id       = AV_CODEC_ID_CELT;
  63.         st->codec->sample_rate    = sample_rate;
  64.         st->codec->channels       = nb_channels;
  65.         st->codec->frame_size     = frame_size;
  66.         if (sample_rate)
  67.             avpriv_set_pts_info(st, 64, 1, sample_rate);
  68.         priv->extra_headers_left  = 1 + extra_headers;
  69.         av_free(os->private);
  70.         os->private = priv;
  71.         AV_WL32(st->codec->extradata + 0, overlap);
  72.         AV_WL32(st->codec->extradata + 4, version);
  73.         return 1;
  74.     } else if (priv && priv->extra_headers_left) {
  75.         /* Extra headers (vorbiscomment) */
  76.  
  77.         ff_vorbis_comment(s, &st->metadata, p, os->psize);
  78.         priv->extra_headers_left--;
  79.         return 1;
  80.     } else {
  81.         return 0;
  82.     }
  83. }
  84.  
  85. const struct ogg_codec ff_celt_codec = {
  86.     .magic     = "CELT    ",
  87.     .magicsize = 8,
  88.     .header    = celt_header,
  89.     .nb_header = 2,
  90. };
  91.