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adp.c
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1 /*
2  * ADP demuxer
3  * Copyright (c) 2013 James Almer
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 
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26 
27 static int adp_probe(AVProbeData *p)
28 {
29  int i, changes = 0;
30  char last = 0;
31 
32  if (p->buf_size < 32)
33  return 0;
34 
35  for (i = 0; i < p->buf_size - 3; i+=32) {
36  if (p->buf[i] != p->buf[i+2] || p->buf[i+1] != p->buf[i+3])
37  return 0;
38  if (p->buf[i] != last)
39  changes++;
40  last = p->buf[i];
41  }
42  if (changes <= 1)
43  return 0;
44 
45  return p->buf_size < 260 ? 1 : AVPROBE_SCORE_MAX / 4;
46 }
47 
49 {
50  AVStream *st;
51 
52  st = avformat_new_stream(s, NULL);
53  if (!st)
54  return AVERROR(ENOMEM);
55 
59  st->codec->channels = 2;
60  st->codec->sample_rate = 48000;
61  st->start_time = 0;
62  if (s->pb->seekable)
64 
65  avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
66 
67  return 0;
68 }
69 
71 {
72  int ret, size = 1024;
73 
74  if (url_feof(s->pb))
75  return AVERROR_EOF;
76 
77  ret = av_get_packet(s->pb, pkt, size);
78 
79  if (ret != size) {
80  if (ret < 0) {
81  av_free_packet(pkt);
82  return ret;
83  }
84  av_shrink_packet(pkt, ret);
85  }
86  pkt->stream_index = 0;
87 
88  return ret;
89 }
90 
92  .name = "adp",
93  .long_name = NULL_IF_CONFIG_SMALL("ADP"),
94  .read_probe = adp_probe,
95  .read_header = adp_read_header,
96  .read_packet = adp_read_packet,
97  .extensions = "adp,dtk",
98 };