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  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
  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.     if (iss->packet_size <= 0) {
  92.         av_log(s, AV_LOG_ERROR, "packet_size %d is invalid\n", iss->packet_size);
  93.         return AVERROR_INVALIDDATA;
  94.     }
  95.  
  96.     iss->sample_start_pos = avio_tell(pb);
  97.  
  98.     st = avformat_new_stream(s, NULL);
  99.     if (!st)
  100.         return AVERROR(ENOMEM);
  101.     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
  102.     st->codec->codec_id = AV_CODEC_ID_ADPCM_IMA_ISS;
  103.     if (stereo) {
  104.         st->codec->channels       = 2;
  105.         st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
  106.     } else {
  107.         st->codec->channels       = 1;
  108.         st->codec->channel_layout = AV_CH_LAYOUT_MONO;
  109.     }
  110.     st->codec->sample_rate = 44100;
  111.     if(rate_divisor > 0)
  112.          st->codec->sample_rate /= rate_divisor;
  113.     st->codec->bits_per_coded_sample = 4;
  114.     st->codec->bit_rate = st->codec->channels * st->codec->sample_rate
  115.                                       * st->codec->bits_per_coded_sample;
  116.     st->codec->block_align = iss->packet_size;
  117.     avpriv_set_pts_info(st, 32, 1, st->codec->sample_rate);
  118.  
  119.     return 0;
  120. }
  121.  
  122. static int iss_read_packet(AVFormatContext *s, AVPacket *pkt)
  123. {
  124.     IssDemuxContext *iss = s->priv_data;
  125.     int ret = av_get_packet(s->pb, pkt, iss->packet_size);
  126.  
  127.     if(ret != iss->packet_size)
  128.         return AVERROR(EIO);
  129.  
  130.     pkt->stream_index = 0;
  131.     pkt->pts = avio_tell(s->pb) - iss->sample_start_pos;
  132.     if(s->streams[0]->codec->channels > 0)
  133.         pkt->pts /= s->streams[0]->codec->channels*2;
  134.     return 0;
  135. }
  136.  
  137. AVInputFormat ff_iss_demuxer = {
  138.     .name           = "iss",
  139.     .long_name      = NULL_IF_CONFIG_SMALL("Funcom ISS"),
  140.     .priv_data_size = sizeof(IssDemuxContext),
  141.     .read_probe     = iss_probe,
  142.     .read_header    = iss_read_header,
  143.     .read_packet    = iss_read_packet,
  144. };
  145.