FFmpeg: libavformat/apc.c Source File

FFmpeg
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 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 <string.h>
23 
24 #include "libavutil/channel_layout.h"
25 #include "avformat.h"
26 #include "internal.h"
27 
28  static int apc_probe(AVProbeData *p)
29 {
30  if (!strncmp(p->buf, "CRYO_APC", 8))
31  return AVPROBE_SCORE_MAX;
32 
33  return 0;
34 }
35 
36  static int apc_read_header(AVFormatContext *s)
37 {
38  AVIOContext *pb = s->pb;
39  AVStream *st;
40 
41  avio_rl32(pb); /* CRYO */
42  avio_rl32(pb); /* _APC */
43  avio_rl32(pb); /* 1.20 */
44 
45  st = avformat_new_stream(s, NULL);
46  if (!st)
47  return AVERROR(ENOMEM);
48 
49  st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
50  st->codecpar->codec_id = AV_CODEC_ID_ADPCM_IMA_APC;
51 
52  avio_rl32(pb); /* number of samples */
53  st->codecpar->sample_rate = avio_rl32(pb);
54 
55  /* initial predictor values for adpcm decoder */
56  if (ff_get_extradata(s, st->codecpar, pb, 2 * 4) < 0)
57  return AVERROR(ENOMEM);
58 
59  if (avio_rl32(pb)) {
60  st->codecpar->channels = 2;
61  st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
62  } else {
63  st->codecpar->channels = 1;
64  st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
65  }
66 
67  st->codecpar->bits_per_coded_sample = 4;
68  st->codecpar->bit_rate = (int64_t)st->codecpar->bits_per_coded_sample * st->codecpar->channels
69  * st->codecpar->sample_rate;
70  st->codecpar->block_align = 1;
71 
72  return 0;
73 }
74 
75  #define MAX_READ_SIZE 4096
76 
77  static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
78 {
79  if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)
80  return AVERROR(EIO);
81  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
82  pkt->stream_index = 0;
83  return 0;
84 }
85 
86  AVInputFormat ff_apc_demuxer = {
87  .name = "apc",
88  .long_name = NULL_IF_CONFIG_SMALL("CRYO APC"),
89  .read_probe = apc_probe,
90  .read_header = apc_read_header,
91  .read_packet = apc_read_packet,
92 };
NULL
#define NULL
Definition: coverity.c:32
s
const char * s
Definition: avisynth_c.h:768
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3884
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:86
AVFormatContext
Format I/O context.
Definition: avformat.h:1342
apc_read_packet
static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: apc.c:77
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4450
av_get_packet
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:310
AVCodecParameters::channel_layout
uint64_t channel_layout
Audio only.
Definition: avcodec.h:3986
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3913
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:770
AVERROR
#define AVERROR(e)
Definition: error.h:43
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3880
AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1436
ff_apc_demuxer
AVInputFormat ff_apc_demuxer
Definition: apc.c:86
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:450
MAX_READ_SIZE
#define MAX_READ_SIZE
Definition: apc.c:75
AVCodecParameters::block_align
int block_align
Audio only.
Definition: avcodec.h:4001
channel_layout.h
audio channel layout utility functions
AV_CODEC_ID_ADPCM_IMA_APC
Definition: avcodec.h:519
AVStream
Stream structure.
Definition: avformat.h:873
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1384
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:448
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: avcodec.h:3994
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:460
apc_read_header
static int apc_read_header(AVFormatContext *s)
Definition: apc.c:36
avformat.h
Main libavformat public API header.
ff_get_extradata
int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0 and f...
Definition: utils.c:3298
AV_PKT_FLAG_CORRUPT
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: avcodec.h:1463
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: avcodec.h:3926
AVCodecParameters::channels
int channels
Audio only.
Definition: avcodec.h:3990
apc_probe
static int apc_probe(AVProbeData *p)
Definition: apc.c:28
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:647
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1020
AVPacket::stream_index
int stream_index
Definition: avcodec.h:1432
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:85
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1407
Generated on Sun May 13 2018 02:04:04 for FFmpeg by   doxygen 1.8.6

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