iss.c
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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 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 
29 #include "avformat.h"
30 #include "internal.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 {
41 
42 static void get_token(AVIOContext *s, char *buf, int maxlen)
43 {
44  int i = 0;
45  char c;
46 
47  while ((c = avio_r8(s))) {
48  if(c == ' ')
49  break;
50  if (i < maxlen-1)
51  buf[i++] = c;
52  }
53 
54  if(!c)
55  avio_r8(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 
69 {
70  IssDemuxContext *iss = s->priv_data;
71  AVIOContext *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 = avio_tell(pb);
91 
92  st = avformat_new_stream(s, NULL);
93  if (!st)
94  return AVERROR(ENOMEM);
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
104  st->codec->block_align = iss->packet_size;
105  avpriv_set_pts_info(st, 32, 1, st->codec->sample_rate);
106 
107  return 0;
108 }
109 
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 = avio_tell(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 
126  .name = "ISS",
127  .long_name = NULL_IF_CONFIG_SMALL("Funcom ISS format"),
128  .priv_data_size = sizeof(IssDemuxContext),
132 };
133