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avr.c
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1 /*
2  * AVR demuxer
3  * Copyright (c) 2012 Paul B Mahol
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 "avformat.h"
24 #include "internal.h"
25 #include "pcm.h"
26 
27 static int avr_probe(AVProbeData *p)
28 {
29  if (AV_RL32(p->buf) != MKTAG('2', 'B', 'I', 'T'))
30  return 0;
31 
32  if (!AV_RB16(p->buf+12) || AV_RB16(p->buf+12) > 256) // channels
33  return AVPROBE_SCORE_EXTENSION/2;
34  if (AV_RB16(p->buf+14) > 256) // bps
35  return AVPROBE_SCORE_EXTENSION/2;
36 
38 }
39 
41 {
42  uint16_t chan, sign, bps;
43  AVStream *st;
44 
45  st = avformat_new_stream(s, NULL);
46  if (!st)
47  return AVERROR(ENOMEM);
48 
50 
51  avio_skip(s->pb, 4); // magic
52  avio_skip(s->pb, 8); // sample_name
53 
54  chan = avio_rb16(s->pb);
55  if (!chan) {
56  st->codecpar->channels = 1;
57  } else if (chan == 0xFFFFu) {
58  st->codecpar->channels = 2;
59  } else {
60  avpriv_request_sample(s, "chan %d", chan);
61  return AVERROR_PATCHWELCOME;
62  }
63 
64  st->codecpar->bits_per_coded_sample = bps = avio_rb16(s->pb);
65 
66  sign = avio_rb16(s->pb);
67 
68  avio_skip(s->pb, 2); // loop
69  avio_skip(s->pb, 2); // midi
70  avio_skip(s->pb, 1); // replay speed
71 
72  st->codecpar->sample_rate = avio_rb24(s->pb);
73  avio_skip(s->pb, 4 * 3);
74  avio_skip(s->pb, 2 * 3);
75  avio_skip(s->pb, 20);
76  avio_skip(s->pb, 64);
77 
78  st->codecpar->codec_id = ff_get_pcm_codec_id(bps, 0, 1, sign);
79  if (st->codecpar->codec_id == AV_CODEC_ID_NONE) {
80  avpriv_request_sample(s, "Bps %d and sign %d", bps, sign);
81  return AVERROR_PATCHWELCOME;
82  }
83 
84  st->codecpar->block_align = bps * st->codecpar->channels / 8;
85 
86  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
87  return 0;
88 }
89 
91  .name = "avr",
92  .long_name = NULL_IF_CONFIG_SMALL("AVR (Audio Visual Research)"),
93  .read_probe = avr_probe,
94  .read_header = avr_read_header,
95  .read_packet = ff_pcm_read_packet,
96  .read_seek = ff_pcm_read_seek,
97  .extensions = "avr",
98  .flags = AVFMT_GENERIC_INDEX,
99 };
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:631
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4399
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3911
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:287
unsigned int avio_rb16(AVIOContext *s)
Definition: aviobuf.c:688
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:87
Format I/O context.
Definition: avformat.h:1319
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4037
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3907
static int avr_probe(AVProbeData *p)
Definition: avr.c:27
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:461
int block_align
Audio only.
Definition: avcodec.h:4028
unsigned int avio_rb24(AVIOContext *s)
Definition: aviobuf.c:696
int ff_pcm_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: pcm.c:45
Stream structure.
Definition: avformat.h:876
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
int ff_pcm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: pcm.c:29
AVIOContext * pb
I/O context.
Definition: avformat.h:1361
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:485
enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags)
Select a PCM codec based on the given parameters.
Definition: utils.c:2953
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:469
This structure contains the data a format has to probe a file.
Definition: avformat.h:459
int sample_rate
Audio only.
Definition: avcodec.h:4021
Main libavformat public API header.
unsigned bps
Definition: movenc.c:1354
static int avr_read_header(AVFormatContext *s)
Definition: avr.c:40
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:3953
int channels
Audio only.
Definition: avcodec.h:4017
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:660
AVCodecParameters * codecpar
Definition: avformat.h:1006
AVInputFormat ff_avr_demuxer
Definition: avr.c:90
#define MKTAG(a, b, c, d)
Definition: common.h:342
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87