FFmpeg
adp.c
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1 /*
2  * ADP demuxer
3  * Copyright (c) 2013 James Almer
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 
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26 
27 static int adp_probe(const AVProbeData *p)
28 {
29  int i, changes = 0;
30  uint8_t last = 0;
31 
32  if (p->buf_size < 32)
33  return 0;
34 
35  for (i = 0; i < p->buf_size - 3; i+=32) {
36  if (p->buf[i] != p->buf[i+2] || p->buf[i+1] != p->buf[i+3])
37  return 0;
38  if (p->buf[i] != last)
39  changes++;
40  last = p->buf[i];
41  }
42  if (changes <= 1)
43  return 0;
44 
45  return p->buf_size < 260 ? 1 : AVPROBE_SCORE_MAX / 4;
46 }
47 
49 {
50  AVStream *st;
51 
52  st = avformat_new_stream(s, NULL);
53  if (!st)
54  return AVERROR(ENOMEM);
55 
59  st->codecpar->channels = 2;
60  st->codecpar->sample_rate = 48000;
61  st->start_time = 0;
62  if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
64 
65  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
66 
67  return 0;
68 }
69 
71 {
72  int ret, size = 1024;
73 
74  if (avio_feof(s->pb))
75  return AVERROR_EOF;
76 
77  ret = av_get_packet(s->pb, pkt, size);
78  if (ret < 0)
79  return ret;
80 
81  pkt->stream_index = 0;
82 
83  return ret;
84 }
85 
87  .name = "adp",
88  .long_name = NULL_IF_CONFIG_SMALL("ADP"),
89  .read_probe = adp_probe,
90  .read_header = adp_read_header,
91  .read_packet = adp_read_packet,
92  .extensions = "adp,dtk",
93 };
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
AV_CODEC_ID_ADPCM_DTK
@ AV_CODEC_ID_ADPCM_DTK
Definition: codec_id.h:385
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
avio_size
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:338
av_get_audio_frame_duration2
int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes)
This function is the same as av_get_audio_frame_duration(), except it works with AVCodecParameters in...
Definition: utils.c:826
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
adp_probe
static int adp_probe(const AVProbeData *p)
Definition: adp.c:27
ff_adp_demuxer
const AVInputFormat ff_adp_demuxer
Definition: adp.c:86
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:888
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
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:631
changes
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is which means that it is highly recommended that you submit your filters to the FFmpeg development mailing list and make sure that they are applied your filters are likely to have a very short lifetime due to more or less regular internal API changes
Definition: writing_filters.txt:8
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
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
adp_read_packet
static int adp_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: adp.c:70
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
size
int size
Definition: twinvq_data.h:10344
adp_read_header
static int adp_read_header(AVFormatContext *s)
Definition: adp.c:48
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
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
AVIO_SEEKABLE_NORMAL
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
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:1146
AVPacket::stream_index
int stream_index
Definition: packet.h:375
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
AVStream::start_time
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base.
Definition: avformat.h:878
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:360