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 
25 #include "avformat.h"
26 #include "internal.h"
27 
28 static int apc_probe(const AVProbeData *p)
29 {
30  if (!strncmp(p->buf, "CRYO_APC", 8))
31  return AVPROBE_SCORE_MAX;
32 
33  return 0;
34 }
35 
37 {
38  AVIOContext *pb = s->pb;
39  AVStream *st;
40  int ret;
41 
42  avio_rl32(pb); /* CRYO */
43  avio_rl32(pb); /* _APC */
44  avio_rl32(pb); /* 1.20 */
45 
46  st = avformat_new_stream(s, NULL);
47  if (!st)
48  return AVERROR(ENOMEM);
49 
52 
53  avio_rl32(pb); /* number of samples */
54  st->codecpar->sample_rate = avio_rl32(pb);
55 
56  /* initial predictor values for adpcm decoder */
57  if ((ret = ff_get_extradata(s, st->codecpar, pb, 2 * 4)) < 0)
58  return ret;
59 
60  if (avio_rl32(pb)) {
61  st->codecpar->channels = 2;
63  } else {
64  st->codecpar->channels = 1;
66  }
67 
70  * st->codecpar->sample_rate;
71  st->codecpar->block_align = 1;
72 
73  return 0;
74 }
75 
76 #define MAX_READ_SIZE 4096
77 
79 {
80  if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)
81  return AVERROR(EIO);
82  pkt->stream_index = 0;
83  return 0;
84 }
85 
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 };
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:724
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
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:469
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:90
apc_read_packet
static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: apc.c:78
ff_apc_demuxer
const AVInputFormat ff_apc_demuxer
Definition: apc.c:86
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:91
pkt
AVPacket * pkt
Definition: movenc.c:59
AVInputFormat
Definition: avformat.h:626
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:631
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AV_CODEC_ID_ADPCM_IMA_APC
@ AV_CODEC_ID_ADPCM_IMA_APC
Definition: codec_id.h:381
apc_probe
static int apc_probe(const AVProbeData *p)
Definition: apc.c:28
AVFormatContext
Format I/O context.
Definition: avformat.h:1097
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:992
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:742
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
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:117
apc_read_header
static int apc_read_header(AVFormatContext *s)
Definition: apc.c:36
AVCodecParameters::block_align
int block_align
Audio only.
Definition: codec_par.h:177
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:196
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:845
avformat.h
channel_layout.h
AVPacket::stream_index
int stream_index
Definition: packet.h:375
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:102
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecParameters::channel_layout
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:89
MAX_READ_SIZE
#define MAX_READ_SIZE
Definition: apc.c:76