FFmpeg
aea.c
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1 /*
2  * MD STUDIO audio demuxer
3  *
4  * Copyright (c) 2009 Benjamin Larsson
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
24 #include "libavutil/intreadwrite.h"
25 #include "avformat.h"
26 #include "demux.h"
27 #include "pcm.h"
28 
29 #define AT1_SU_SIZE 212
30 
31 static int aea_read_probe(const AVProbeData *p)
32 {
33  if (p->buf_size <= 2048+AT1_SU_SIZE)
34  return 0;
35 
36  /* Magic is '00 08 00 00' in little-endian*/
37  if (AV_RL32(p->buf)==0x800) {
38  int ch, block_size, score = 0;
39  ch = p->buf[264];
40 
41  if (ch != 1 && ch != 2)
42  return 0;
43 
44  block_size = ch * AT1_SU_SIZE;
45  /* Check so that the redundant bsm bytes and info bytes are valid
46  * the block size mode bytes have to be the same
47  * the info bytes have to be the same
48  */
49  for (int i = 2048 + block_size; i + block_size <= p->buf_size; i += block_size) {
50  if (AV_RN16(p->buf+i) != AV_RN16(p->buf+i+AT1_SU_SIZE))
51  return 0;
52  score++;
53  }
54  return FFMIN(AVPROBE_SCORE_MAX / 4 + score, AVPROBE_SCORE_MAX);
55  }
56  return 0;
57 }
58 
60 {
62  int channels;
63  if (!st)
64  return AVERROR(ENOMEM);
65 
66  /* Parse the amount of channels and skip to pos 2048(0x800) */
67  avio_skip(s->pb, 264);
68  channels = avio_r8(s->pb);
69  avio_skip(s->pb, 1783);
70 
71 
74  st->codecpar->sample_rate = 44100;
75  st->codecpar->bit_rate = 146000 * channels;
76 
77  if (channels != 1 && channels != 2) {
78  av_log(s, AV_LOG_ERROR, "Channels %d not supported!\n", channels);
79  return AVERROR_INVALIDDATA;
80  }
81 
83 
85  return 0;
86 }
87 
89 {
90  return av_get_packet(s->pb, pkt, s->streams[0]->codecpar->block_align);
91 }
92 
94  .p.name = "aea",
95  .p.long_name = NULL_IF_CONFIG_SMALL("MD STUDIO audio"),
96  .p.flags = AVFMT_GENERIC_INDEX,
97  .p.extensions = "aea",
98  .read_probe = aea_read_probe,
99  .read_header = aea_read_header,
100  .read_packet = aea_read_packet,
101  .read_seek = ff_pcm_read_seek,
102 };
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
pcm.h
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AV_RN16
#define AV_RN16(p)
Definition: intreadwrite.h:358
aea_read_probe
static int aea_read_probe(const AVProbeData *p)
Definition: aea.c:31
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:454
AVChannelLayout::nb_channels
int nb_channels
Number of channels in this layout.
Definition: channel_layout.h:313
AT1_SU_SIZE
#define AT1_SU_SIZE
Definition: aea.c:29
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:463
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:480
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
channels
channels
Definition: aptx.h:31
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
AVCodecParameters::ch_layout
AVChannelLayout ch_layout
Audio only.
Definition: codec_par.h:180
aea_read_packet
static int aea_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: aea.c:88
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:184
aea_read_header
static int aea_read_header(AVFormatContext *s)
Definition: aea.c:59
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:106
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:35
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:602
av_channel_layout_default
void av_channel_layout_default(AVChannelLayout *ch_layout, int nb_channels)
Get the default channel layout for a given number of channels.
Definition: channel_layout.c:841
AV_CODEC_ID_ATRAC1
@ AV_CODEC_ID_ATRAC1
Definition: codec_id.h:486
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
AVCodecParameters::block_align
int block_align
Audio only.
Definition: codec_par.h:191
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
demux.h
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:103
AVStream
Stream structure.
Definition: avformat.h:743
ff_pcm_read_seek
int ff_pcm_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: pcm.c:56
avformat.h
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
channel_layout.h
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:317
ff_aea_demuxer
const FFInputFormat ff_aea_demuxer
Definition: aea.c:93
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:499
FFInputFormat
Definition: demux.h:31
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:97
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61