Libav
apc.c
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1 /*
2  * CRYO APC audio format demuxer
3  * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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 <string.h>
23 
25 #include "avformat.h"
26 
27 static int apc_probe(AVProbeData *p)
28 {
29  if (!strncmp(p->buf, "CRYO_APC", 8))
30  return AVPROBE_SCORE_MAX;
31 
32  return 0;
33 }
34 
36 {
37  AVIOContext *pb = s->pb;
38  AVStream *st;
39 
40  avio_rl32(pb); /* CRYO */
41  avio_rl32(pb); /* _APC */
42  avio_rl32(pb); /* 1.20 */
43 
44  st = avformat_new_stream(s, NULL);
45  if (!st)
46  return AVERROR(ENOMEM);
47 
50 
51  avio_rl32(pb); /* number of samples */
52  st->codec->sample_rate = avio_rl32(pb);
53 
54  st->codec->extradata_size = 2 * 4;
57  if (!st->codec->extradata)
58  return AVERROR(ENOMEM);
59 
60  /* initial predictor values for adpcm decoder */
61  avio_read(pb, st->codec->extradata, 2 * 4);
62 
63  if (avio_rl32(pb)) {
64  st->codec->channels = 2;
66  } else {
67  st->codec->channels = 1;
69  }
70 
73  * st->codec->sample_rate;
74  st->codec->block_align = 1;
75 
76  return 0;
77 }
78 
79 #define MAX_READ_SIZE 4096
80 
82 {
83  if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)
84  return AVERROR(EIO);
85  pkt->stream_index = 0;
86  return 0;
87 }
88 
90  .name = "apc",
91  .long_name = NULL_IF_CONFIG_SMALL("CRYO APC"),
92  .read_probe = apc_probe,
93  .read_header = apc_read_header,
94  .read_packet = apc_read_packet,
95 };
void * av_malloc(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:62
Bytestream IO Context.
Definition: avio.h:68
#define AV_CH_LAYOUT_STEREO
int block_align
number of bytes per packet if constant and known or 0 Used by some WAV based audio codecs...
Definition: avcodec.h:1816
Format I/O context.
Definition: avformat.h:871
static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: apc.c:81
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1162
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:118
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:2481
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:446
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:558
#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:142
AVStream * avformat_new_stream(AVFormatContext *s, AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:2662
AVInputFormat ff_apc_demuxer
Definition: apc.c:89
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:1840
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:702
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:390
#define FF_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:509
#define MAX_READ_SIZE
Definition: apc.c:79
int bit_rate
the average bitrate
Definition: avcodec.h:1112
audio channel layout utility functions
Stream structure.
Definition: avformat.h:683
NULL
Definition: eval.c:55
enum AVMediaType codec_type
Definition: avcodec.h:1062
enum AVCodecID codec_id
Definition: avcodec.h:1065
int sample_rate
samples per second
Definition: avcodec.h:1779
AVIOContext * pb
I/O context.
Definition: avformat.h:913
int extradata_size
Definition: avcodec.h:1163
This structure contains the data a format has to probe a file.
Definition: avformat.h:388
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:395
static int apc_read_header(AVFormatContext *s)
Definition: apc.c:35
Main libavformat public API header.
int channels
number of audio channels
Definition: avcodec.h:1780
static int apc_probe(AVProbeData *p)
Definition: apc.c:27
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:516
int stream_index
Definition: avcodec.h:975
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:950