libavformat/iss.c

   1 /*
   2  * ISS (.iss) file demuxer
   3  * Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net>
   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  * Funcom ISS file demuxer
  25  * @author Jaikrishnan Menon
  26  * @see http://wiki.multimedia.cx/index.php?title=FunCom_ISS
  27  */
  28
  29 #include "libavutil/channel_layout.h"
  30 #include "avformat.h"
  31 #include "internal.h"
  32 #include "libavutil/avstring.h"
  33
  34 #define ISS_SIG "IMA_ADPCM_Sound"
  35 #define ISS_SIG_LEN 15
  36 #define MAX_TOKEN_SIZE 20
  37
  38 typedef struct {
  39     int packet_size;
  40     int sample_start_pos;
  41 } IssDemuxContext;
  42
  43 static void get_token(AVIOContext *s, char *buf, int maxlen)
  44 {
  45     int i = 0;
  46     char c;
  47
  48     while ((c = avio_r8(s))) {
  49         if(c == ' ')
  50             break;
  51         if (i < maxlen-1)
  52             buf[i++] = c;
  53     }
  54
  55     if(!c)
  56         avio_r8(s);
  57
  58     buf[i] = 0; /* Ensure null terminated, but may be truncated */
  59 }
  60
  61 static int iss_probe(AVProbeData *p)
  62 {
  63     if (strncmp(p->buf, ISS_SIG, ISS_SIG_LEN))
  64         return 0;
  65
  66     return AVPROBE_SCORE_MAX;
  67 }
  68
  69 static av_cold int iss_read_header(AVFormatContext *s)
  70 {
  71     IssDemuxContext *iss = s->priv_data;
  72     AVIOContext *pb = s->pb;
  73     AVStream *st;
  74     char token[MAX_TOKEN_SIZE];
  75     int stereo, rate_divisor;
  76
  77     get_token(pb, token, sizeof(token)); //"IMA_ADPCM_Sound"
  78     get_token(pb, token, sizeof(token)); //packet size
  79     sscanf(token, "%d", &iss->packet_size);
  80     get_token(pb, token, sizeof(token)); //File ID
  81     get_token(pb, token, sizeof(token)); //out size
  82     get_token(pb, token, sizeof(token)); //stereo
  83     sscanf(token, "%d", &stereo);
  84     get_token(pb, token, sizeof(token)); //Unknown1
  85     get_token(pb, token, sizeof(token)); //RateDivisor
  86     sscanf(token, "%d", &rate_divisor);
  87     get_token(pb, token, sizeof(token)); //Unknown2
  88     get_token(pb, token, sizeof(token)); //Version ID
  89     get_token(pb, token, sizeof(token)); //Size
  90
  91     iss->sample_start_pos = avio_tell(pb);
  92
  93     st = avformat_new_stream(s, NULL);
  94     if (!st)
  95         return AVERROR(ENOMEM);
  96     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  97     st->codec->codec_id = AV_CODEC_ID_ADPCM_IMA_ISS;
  98     if (stereo) {
  99         st->codec->channels       = 2;
 100         st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
 101     } else {
 102         st->codec->channels       = 1;
 103         st->codec->channel_layout = AV_CH_LAYOUT_MONO;
 104     }
 105     st->codec->sample_rate = 44100;
 106     if(rate_divisor > 0)
 107          st->codec->sample_rate /= rate_divisor;
 108     st->codec->bits_per_coded_sample = 4;
 109     st->codec->bit_rate = st->codec->channels * st->codec->sample_rate
 110                                       * st->codec->bits_per_coded_sample;
 111     st->codec->block_align = iss->packet_size;
 112     avpriv_set_pts_info(st, 32, 1, st->codec->sample_rate);
 113
 114     return 0;
 115 }
 116
 117 static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)
 118 {
 119     IssDemuxContext *iss = s->priv_data;
 120     int ret = av_get_packet(s->pb, pkt, iss->packet_size);
 121
 122     if(ret != iss->packet_size)
 123         return AVERROR(EIO);
 124
 125     pkt->stream_index = 0;
 126     pkt->pts = avio_tell(s->pb) - iss->sample_start_pos;
 127     if(s->streams[0]->codec->channels > 0)
 128         pkt->pts /= s->streams[0]->codec->channels*2;
 129     return 0;
 130 }
 131
 132 AVInputFormat ff_iss_demuxer = {
 133     .name           = "iss",
 134     .long_name      = NULL_IF_CONFIG_SMALL("Funcom ISS"),
 135     .priv_data_size = sizeof(IssDemuxContext),
 136     .read_probe     = iss_probe,
 137     .read_header    = iss_read_header,
 138     .read_packet    = iss_read_packet,
 139 };