FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
vocdec.c
Go to the documentation of this file.
1 /*
2  * Creative Voice File demuxer.
3  * Copyright (c) 2006 Aurelien Jacobs <aurel@gnuage.org>
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 #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
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_EOF;
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  if (!dec->sample_rate) {
90  dec->sample_rate = 1000000 / (256 - avio_r8(pb));
91  if (sample_rate)
92  dec->sample_rate = sample_rate;
93  avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
94  dec->channels = channels;
96  } else
97  avio_skip(pb, 1);
98  tmp_codec = avio_r8(pb);
99  voc->remaining_size -= 2;
100  max_size -= 2;
101  channels = 1;
102  break;
103 
105  break;
106 
107  case VOC_TYPE_EXTENDED:
108  sample_rate = avio_rl16(pb);
109  avio_r8(pb);
110  channels = avio_r8(pb) + 1;
111  sample_rate = 256000000 / (channels * (65536 - sample_rate));
112  voc->remaining_size = 0;
113  max_size -= 4;
114  break;
115 
117  if (!dec->sample_rate) {
118  dec->sample_rate = avio_rl32(pb);
119  avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
120  dec->bits_per_coded_sample = avio_r8(pb);
121  dec->channels = avio_r8(pb);
122  } else
123  avio_skip(pb, 6);
124  tmp_codec = avio_rl16(pb);
125  avio_skip(pb, 4);
126  voc->remaining_size -= 12;
127  max_size -= 12;
128  break;
129 
130  default:
131  avio_skip(pb, voc->remaining_size);
132  max_size -= voc->remaining_size;
133  voc->remaining_size = 0;
134  break;
135  }
136  }
137 
138  if (tmp_codec >= 0) {
139  tmp_codec = ff_codec_get_id(ff_voc_codec_tags, tmp_codec);
140  if (dec->codec_id == AV_CODEC_ID_NONE)
141  dec->codec_id = tmp_codec;
142  else if (dec->codec_id != tmp_codec)
143  av_log(s, AV_LOG_WARNING, "Ignoring mid-stream change in audio codec\n");
144  if (dec->codec_id == AV_CODEC_ID_NONE) {
145  if (s->audio_codec_id == AV_CODEC_ID_NONE) {
146  av_log(s, AV_LOG_ERROR, "unknown codec tag\n");
147  return AVERROR(EINVAL);
148  }
149  av_log(s, AV_LOG_WARNING, "unknown codec tag\n");
150  }
151  }
152 
153  dec->bit_rate = dec->sample_rate * dec->channels * dec->bits_per_coded_sample;
154 
155  if (max_size <= 0)
156  max_size = 2048;
157  size = FFMIN(voc->remaining_size, max_size);
158  voc->remaining_size -= size;
159  return av_get_packet(pb, pkt, size);
160 }
161 
163 {
164  return ff_voc_get_packet(s, pkt, s->streams[0], 0);
165 }
166 
168  .name = "voc",
169  .long_name = NULL_IF_CONFIG_SMALL("Creative Voice"),
170  .priv_data_size = sizeof(VocDecContext),
174  .codec_tag = (const AVCodecTag* const []){ ff_voc_codec_tags, 0 },
175 };