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