libavformat/oggparsecelt.c

   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 "libavutil/mem.h"
  26 #include "avformat.h"
  27 #include "internal.h"
  28 #include "oggdec.h"
  29
  30 struct oggcelt_private {
  31     int extra_headers_left;
  32 };
  33
  34 static int celt_header(AVFormatContext *s, int idx)
  35 {
  36     struct ogg *ogg = s->priv_data;
  37     struct ogg_stream *os = ogg->streams + idx;
  38     AVStream *st = s->streams[idx];
  39     struct oggcelt_private *priv = os->private;
  40     uint8_t *p = os->buf + os->pstart;
  41     int ret;
  42
  43     if (os->psize == 60 &&
  44         !memcmp(p, ff_celt_codec.magic, ff_celt_codec.magicsize)) {
  45         /* Main header */
  46
  47         uint32_t version, sample_rate, nb_channels;
  48         uint32_t overlap, extra_headers;
  49
  50         priv = av_malloc(sizeof(struct oggcelt_private));
  51         if (!priv)
  52             return AVERROR(ENOMEM);
  53         ret = ff_alloc_extradata(st->codecpar, 2 * sizeof(uint32_t));
  54         if (ret < 0) {
  55             av_free(priv);
  56             return ret;
  57         }
  58         version          = AV_RL32(p + 28);
  59         /* unused header size field skipped */
  60         sample_rate      = AV_RL32(p + 36);
  61         nb_channels      = AV_RL32(p + 40);
  62         overlap          = AV_RL32(p + 48);
  63         /* unused bytes per packet field skipped */
  64         extra_headers    = AV_RL32(p + 56);
  65         st->codecpar->codec_type     = AVMEDIA_TYPE_AUDIO;
  66         st->codecpar->codec_id       = AV_CODEC_ID_CELT;
  67         st->codecpar->sample_rate    = sample_rate;
  68         st->codecpar->ch_layout.nb_channels = nb_channels;
  69         if (sample_rate)
  70             avpriv_set_pts_info(st, 64, 1, sample_rate);
  71
  72         if (os->private) {
  73             av_free(priv);
  74             priv = os->private;
  75         }
  76         os->private = priv;
  77         priv->extra_headers_left  = 1 + extra_headers;
  78
  79         AV_WL32(st->codecpar->extradata + 0, overlap);
  80         AV_WL32(st->codecpar->extradata + 4, version);
  81         return 1;
  82     } else if (priv && priv->extra_headers_left) {
  83         /* Extra headers (vorbiscomment) */
  84
  85         ff_vorbis_stream_comment(s, st, p, os->psize);
  86         priv->extra_headers_left--;
  87         return 1;
  88     } else {
  89         return 0;
  90     }
  91 }
  92
  93 const struct ogg_codec ff_celt_codec = {
  94     .magic     = "CELT    ",
  95     .magicsize = 8,
  96     .header    = celt_header,
  97     .nb_header = 2,
  98 };