libavformat/vocdec.c

   1 /*
   2  * Creative Voice File demuxer.
   3  * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>
   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 "libavutil/intreadwrite.h"
  23 #include "voc.h"
  24
  25
  26 static int voc_probe(AVProbeData *p)
  27 {
  28     int version, check;
  29
  30     if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))
  31         return 0;
  32     version = AV_RL16(p->buf + 22);
  33     check = AV_RL16(p->buf + 24);
  34     if (~version + 0x1234 != check)
  35         return 10;
  36
  37     return AVPROBE_SCORE_MAX;
  38 }
  39
  40 static int voc_read_header(AVFormatContext *s, AVFormatParameters *ap)
  41 {
  42     VocDecContext *voc = s->priv_data;
  43     ByteIOContext *pb = s->pb;
  44     int header_size;
  45     AVStream *st;
  46
  47     url_fskip(pb, 20);
  48     header_size = get_le16(pb) - 22;
  49     if (header_size != 4) {
  50         av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);
  51         return AVERROR(ENOSYS);
  52     }
  53     url_fskip(pb, header_size);
  54     st = av_new_stream(s, 0);
  55     if (!st)
  56         return AVERROR(ENOMEM);
  57     st->codec->codec_type = CODEC_TYPE_AUDIO;
  58
  59     voc->remaining_size = 0;
  60     return 0;
  61 }
  62
  63 int
  64 voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
  65 {
  66     VocDecContext *voc = s->priv_data;
  67     AVCodecContext *dec = st->codec;
  68     ByteIOContext *pb = s->pb;
  69     VocType type;
  70     int size;
  71     int sample_rate = 0;
  72     int channels = 1;
  73
  74     while (!voc->remaining_size) {
  75         type = get_byte(pb);
  76         if (type == VOC_TYPE_EOF)
  77             return AVERROR(EIO);
  78         voc->remaining_size = get_le24(pb);
  79         max_size -= 4;
  80
  81         switch (type) {
  82         case VOC_TYPE_VOICE_DATA:
  83             dec->sample_rate = 1000000 / (256 - get_byte(pb));
  84             if (sample_rate)
  85                 dec->sample_rate = sample_rate;
  86             dec->channels = channels;
  87             dec->codec_id = ff_codec_get_id(ff_voc_codec_tags, get_byte(pb));
  88             dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id);
  89             voc->remaining_size -= 2;
  90             max_size -= 2;
  91             channels = 1;
  92             break;
  93
  94         case VOC_TYPE_VOICE_DATA_CONT:
  95             break;
  96
  97         case VOC_TYPE_EXTENDED:
  98             sample_rate = get_le16(pb);
  99             get_byte(pb);
 100             channels = get_byte(pb) + 1;
 101             sample_rate = 256000000 / (channels * (65536 - sample_rate));
 102             voc->remaining_size = 0;
 103             max_size -= 4;
 104             break;
 105
 106         case VOC_TYPE_NEW_VOICE_DATA:
 107             dec->sample_rate = get_le32(pb);
 108             dec->bits_per_coded_sample = get_byte(pb);
 109             dec->channels = get_byte(pb);
 110             dec->codec_id = ff_codec_get_id(ff_voc_codec_tags, get_le16(pb));
 111             url_fskip(pb, 4);
 112             voc->remaining_size -= 12;
 113             max_size -= 12;
 114             break;
 115
 116         default:
 117             url_fskip(pb, voc->remaining_size);
 118             max_size -= voc->remaining_size;
 119             voc->remaining_size = 0;
 120             break;
 121         }
 122     }
 123
 124     dec->bit_rate = dec->sample_rate * dec->bits_per_coded_sample;
 125
 126     if (max_size <= 0)
 127         max_size = 2048;
 128     size = FFMIN(voc->remaining_size, max_size);
 129     voc->remaining_size -= size;
 130     return av_get_packet(pb, pkt, size);
 131 }
 132
 133 static int voc_read_packet(AVFormatContext *s, AVPacket *pkt)
 134 {
 135     return voc_get_packet(s, pkt, s->streams[0], 0);
 136 }
 137
 138 AVInputFormat voc_demuxer = {
 139     "voc",
 140     NULL_IF_CONFIG_SMALL("Creative Voice file format"),
 141     sizeof(VocDecContext),
 142     voc_probe,
 143     voc_read_header,
 144     voc_read_packet,
 145     .codec_tag=(const AVCodecTag* const []){ff_voc_codec_tags, 0},
 146 };