vocdec.c
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1 /*
2  * Creative Voice File demuxer.
3  * Copyright (c) 2006 Aurelien Jacobs <aurel@gnuage.org>
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 #include "libavutil/intreadwrite.h"
23 #include "voc.h"
24 #include "internal.h"
25 
26 
27 static int voc_probe(AVProbeData *p)
28 {
29  int version, check;
30 
31  if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))
32  return 0;
33  version = AV_RL16(p->buf + 22);
34  check = AV_RL16(p->buf + 24);
35  if (~version + 0x1234 != check)
36  return 10;
37 
38  return AVPROBE_SCORE_MAX;
39 }
40 
42 {
43  VocDecContext *voc = s->priv_data;
44  AVIOContext *pb = s->pb;
45  int header_size;
46  AVStream *st;
47 
48  avio_skip(pb, 20);
49  header_size = avio_rl16(pb) - 22;
50  if (header_size != 4) {
51  av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);
52  return AVERROR(ENOSYS);
53  }
54  avio_skip(pb, header_size);
55  st = avformat_new_stream(s, NULL);
56  if (!st)
57  return AVERROR(ENOMEM);
59 
60  voc->remaining_size = 0;
61  return 0;
62 }
63 
64 int
65 voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
66 {
67  VocDecContext *voc = s->priv_data;
68  AVCodecContext *dec = st->codec;
69  AVIOContext *pb = s->pb;
70  VocType type;
71  int size, tmp_codec=-1;
72  int sample_rate = 0;
73  int channels = 1;
74 
75  while (!voc->remaining_size) {
76  type = avio_r8(pb);
77  if (type == VOC_TYPE_EOF)
78  return AVERROR(EIO);
79  voc->remaining_size = avio_rl24(pb);
80  if (!voc->remaining_size) {
81  if (!s->pb->seekable)
82  return AVERROR(EIO);
83  voc->remaining_size = avio_size(pb) - avio_tell(pb);
84  }
85  max_size -= 4;
86 
87  switch (type) {
89  dec->sample_rate = 1000000 / (256 - avio_r8(pb));
90  if (sample_rate)
91  dec->sample_rate = sample_rate;
92  dec->channels = channels;
93  tmp_codec = avio_r8(pb);
95  voc->remaining_size -= 2;
96  max_size -= 2;
97  channels = 1;
98  break;
99 
101  break;
102 
103  case VOC_TYPE_EXTENDED:
104  sample_rate = avio_rl16(pb);
105  avio_r8(pb);
106  channels = avio_r8(pb) + 1;
107  sample_rate = 256000000 / (channels * (65536 - sample_rate));
108  voc->remaining_size = 0;
109  max_size -= 4;
110  break;
111 
113  dec->sample_rate = avio_rl32(pb);
114  dec->bits_per_coded_sample = avio_r8(pb);
115  dec->channels = avio_r8(pb);
116  tmp_codec = avio_rl16(pb);
117  avio_skip(pb, 4);
118  voc->remaining_size -= 12;
119  max_size -= 12;
120  break;
121 
122  default:
123  avio_skip(pb, voc->remaining_size);
124  max_size -= voc->remaining_size;
125  voc->remaining_size = 0;
126  break;
127  }
128  }
129 
130  if (tmp_codec >= 0) {
131  tmp_codec = ff_codec_get_id(ff_voc_codec_tags, tmp_codec);
132  if (dec->codec_id == CODEC_ID_NONE)
133  dec->codec_id = tmp_codec;
134  else if (dec->codec_id != tmp_codec)
135  av_log(s, AV_LOG_WARNING, "Ignoring mid-stream change in audio codec\n");
136  if (dec->codec_id == CODEC_ID_NONE) {
137  if (s->audio_codec_id == CODEC_ID_NONE) {
138  av_log(s, AV_LOG_ERROR, "unknown codec tag\n");
139  return AVERROR(EINVAL);
140  }
141  av_log(s, AV_LOG_WARNING, "unknown codec tag\n");
142  }
143  }
144 
145  dec->bit_rate = dec->sample_rate * dec->bits_per_coded_sample;
146 
147  if (max_size <= 0)
148  max_size = 2048;
149  size = FFMIN(voc->remaining_size, max_size);
150  voc->remaining_size -= size;
151  return av_get_packet(pb, pkt, size);
152 }
153 
155 {
156  return voc_get_packet(s, pkt, s->streams[0], 0);
157 }
158 
160  .name = "voc",
161  .long_name = NULL_IF_CONFIG_SMALL("Creative Voice file format"),
162  .priv_data_size = sizeof(VocDecContext),
166  .codec_tag=(const AVCodecTag* const []){ff_voc_codec_tags, 0},
167 };