libavformat/eacdata.c

   1 /*
   2  * Electronic Arts .cdata file Demuxer
   3  * Copyright (c) 2007 Peter Ross
   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 /**
  23  * @file
  24  * Electronic Arts cdata Format Demuxer
  25  * by Peter Ross (pross@xvid.org)
  26  *
  27  * Technical details here:
  28  *  http://wiki.multimedia.cx/index.php?title=EA_Command_And_Conquer_3_Audio_Codec
  29  */
  30
  31 #include "avformat.h"
  32 #include "internal.h"
  33
  34 typedef struct {
  35   unsigned int channels;
  36   unsigned int audio_pts;
  37 } CdataDemuxContext;
  38
  39 static int cdata_probe(AVProbeData *p)
  40 {
  41     const uint8_t *b = p->buf;
  42
  43     if (b[0] == 0x04 && (b[1] == 0x00 || b[1] == 0x04 || b[1] == 0x0C))
  44         return AVPROBE_SCORE_MAX/8;
  45     return 0;
  46 }
  47
  48 static int cdata_read_header(AVFormatContext *s)
  49 {
  50     CdataDemuxContext *cdata = s->priv_data;
  51     AVIOContext *pb = s->pb;
  52     unsigned int sample_rate, header;
  53     AVStream *st;
  54
  55     header = avio_rb16(pb);
  56     switch (header) {
  57         case 0x0400: cdata->channels = 1; break;
  58         case 0x0404: cdata->channels = 2; break;
  59         case 0x040C: cdata->channels = 4; break;
  60         default:
  61             av_log(s, AV_LOG_INFO, "unknown header 0x%04x\n", header);
  62             return -1;
  63     };
  64
  65     sample_rate = avio_rb16(pb);
  66     avio_skip(pb, 12);
  67
  68     st = avformat_new_stream(s, NULL);
  69     if (!st)
  70         return AVERROR(ENOMEM);
  71     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  72     st->codec->codec_tag = 0; /* no fourcc */
  73     st->codec->codec_id = AV_CODEC_ID_ADPCM_EA_XAS;
  74     st->codec->channels = cdata->channels;
  75     st->codec->sample_rate = sample_rate;
  76     avpriv_set_pts_info(st, 64, 1, sample_rate);
  77
  78     cdata->audio_pts = 0;
  79     return 0;
  80 }
  81
  82 static int cdata_read_packet(AVFormatContext *s, AVPacket *pkt)
  83 {
  84     CdataDemuxContext *cdata = s->priv_data;
  85     int packet_size = 76*cdata->channels;
  86
  87     int ret = av_get_packet(s->pb, pkt, packet_size);
  88     if (ret < 0)
  89         return ret;
  90     pkt->pts = cdata->audio_pts++;
  91     return 0;
  92 }
  93
  94 AVInputFormat ff_ea_cdata_demuxer = {
  95     .name           = "ea_cdata",
  96     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts cdata"),
  97     .priv_data_size = sizeof(CdataDemuxContext),
  98     .read_probe     = cdata_probe,
  99     .read_header    = cdata_read_header,
 100     .read_packet    = cdata_read_packet,
 101     .extensions = "cdata",
 102 };