FFmpeg
g723_1.c
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1 /*
2  * G.723.1 demuxer
3  * Copyright (c) 2010 Mohamed Naufal Basheer
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 /**
23  * @file
24  * G.723.1 demuxer
25  */
26 
27 #include "libavutil/attributes.h"
29 #include "avformat.h"
30 #include "internal.h"
31 
32 static const uint8_t frame_size[4] = { 24, 20, 4, 1 };
33 
35 {
36  AVStream *st;
37 
38  st = avformat_new_stream(s, NULL);
39  if (!st)
40  return AVERROR(ENOMEM);
41 
45  st->codecpar->channels = 1;
46  st->codecpar->sample_rate = 8000;
47 
48  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
49  st->start_time = 0;
50 
51  return 0;
52 }
53 
55 {
56  int size, byte, ret;
57 
58  pkt->pos = avio_tell(s->pb);
59  byte = avio_r8(s->pb);
60  size = frame_size[byte & 3];
61 
63  if (ret < 0)
64  return ret;
65 
66  pkt->data[0] = byte;
67  pkt->duration = 240;
68  pkt->stream_index = 0;
69 
70  ret = avio_read(s->pb, pkt->data + 1, size - 1);
71  if (ret < size - 1) {
72  return ret < 0 ? ret : AVERROR_EOF;
73  }
74 
75  return pkt->size;
76 }
77 
79  .name = "g723_1",
80  .long_name = NULL_IF_CONFIG_SMALL("G.723.1"),
81  .read_header = g723_1_init,
82  .read_packet = g723_1_read_packet,
83  .extensions = "tco,rco,g723_1",
84  .flags = AVFMT_GENERIC_INDEX
85 };
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
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:90
AVPacket::data
uint8_t * data
Definition: packet.h:373
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:391
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:486
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
pkt
AVPacket * pkt
Definition: movenc.c:59
AVInputFormat
Definition: avformat.h:626
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:257
av_new_packet
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:99
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:631
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
g723_1_init
static av_cold int g723_1_init(AVFormatContext *s)
Definition: g723_1.c:34
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
AV_CODEC_ID_G723_1
@ AV_CODEC_ID_G723_1
Definition: codec_id.h:474
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
AVPacket::size
int size
Definition: packet.h:374
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
byte
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_WB16 unsigned int_TMPL byte
Definition: bytestream.h:99
ff_g723_1_demuxer
const AVInputFormat ff_g723_1_demuxer
Definition: g723_1.c:78
size
int size
Definition: twinvq_data.h:10344
g723_1_read_packet
static int g723_1_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: g723_1.c:54
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:616
attributes.h
frame_size
static const uint8_t frame_size[4]
Definition: g723_1.c:32
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:845
avformat.h
channel_layout.h
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:625
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
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:393
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