FFmpeg
derf.c
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1 /*
2  * DERF demuxer
3  * Copyright (c) 2020 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/channel_layout.h"
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "pcm.h"
27 
28 static int derf_probe(const AVProbeData *p)
29 {
30  if (AV_RL32(p->buf) != MKTAG('D','E','R','F'))
31  return 0;
32  if (AV_RL32(p->buf+4) != 1 && AV_RL32(p->buf+4) != 2)
33  return 0;
34 
35  return AVPROBE_SCORE_MAX / 3 * 2;
36 }
37 
38 static int derf_read_header(AVFormatContext *s)
39 {
40  unsigned data_size;
41  AVIOContext *pb = s->pb;
42  AVCodecParameters *par;
43  AVStream *st;
44 
45  avio_skip(pb, 4);
46 
47  st = avformat_new_stream(s, NULL);
48  if (!st)
49  return AVERROR(ENOMEM);
50 
51  par = st->codecpar;
52  par->codec_type = AVMEDIA_TYPE_AUDIO;
53  par->codec_id = AV_CODEC_ID_DERF_DPCM;
54  par->format = AV_SAMPLE_FMT_S16;
55  par->channels = avio_rl32(pb);
56  if (par->channels != 1 && par->channels != 2)
57  return AVERROR_INVALIDDATA;
58  if (par->channels == 1)
59  par->channel_layout = AV_CH_LAYOUT_MONO;
60  else if (par->channels == 2)
61  par->channel_layout = AV_CH_LAYOUT_STEREO;
62  data_size = avio_rl32(pb);
63  st->duration = data_size / par->channels;
64  par->sample_rate = 22050;
65  par->block_align = 1;
66 
67  avpriv_set_pts_info(st, 64, 1, par->sample_rate);
68 
69  return 0;
70 }
71 
72 const AVInputFormat ff_derf_demuxer = {
73  .name = "derf",
74  .long_name = NULL_IF_CONFIG_SMALL("Xilam DERF"),
75  .read_probe = derf_probe,
76  .read_header = derf_read_header,
77  .read_packet = ff_pcm_read_packet,
78  .read_seek = ff_pcm_read_seek,
79  .extensions = "adp",
80 };
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:768
pcm.h
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
AVCodecParameters
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:90
derf_read_header
static int derf_read_header(AVFormatContext *s)
Definition: derf.c:38
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:459
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:985
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:91
AVInputFormat
Definition: avformat.h:650
intreadwrite.h
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:655
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:449
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AV_CODEC_ID_DERF_DPCM
@ AV_CODEC_ID_DERF_DPCM
Definition: codec_id.h:420
AVFormatContext
Format I/O context.
Definition: avformat.h:1200
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1095
NULL
#define NULL
Definition: coverity.c:32
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:447
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
ff_derf_demuxer
const AVInputFormat ff_derf_demuxer
Definition: derf.c:72
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
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
derf_probe
static int derf_probe(const AVProbeData *p)
Definition: derf.c:28
AVCodecParameters::block_align
int block_align
Audio only.
Definition: codec_par.h:177
AV_SAMPLE_FMT_S16
@ AV_SAMPLE_FMT_S16
signed 16 bits
Definition: samplefmt.h:61
ff_pcm_read_packet
int ff_pcm_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: pcm.c:29
AVStream
Stream structure.
Definition: avformat.h:935
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
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, 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:1196
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
AVCodecParameters::format
int format
Definition: codec_par.h:84
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVCodecParameters::channel_layout
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
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