FFmpeg
bit.c
Go to the documentation of this file.
1 /*
2  * G.729 bit format muxer and demuxer
3  * Copyright (c) 2007-2008 Vladimir Voroshilov
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 #include "avformat.h"
22 #include "internal.h"
23 #include "libavcodec/get_bits.h"
24 #include "libavcodec/put_bits.h"
25 
26 #define MAX_FRAME_SIZE 10
27 
28 #define SYNC_WORD 0x6b21
29 #define BIT_0 0x7f
30 #define BIT_1 0x81
31 
32 #if CONFIG_BIT_DEMUXER
33 static int probe(const AVProbeData *p)
34 {
35  int i = 0, j, valid = 0;
36 
37  while (2 * i + 3 < p->buf_size){
38  if (AV_RL16(&p->buf[2 * i++]) != SYNC_WORD)
39  return 0;
40  j = AV_RL16(&p->buf[2 * i++]);
41  if (j != 0 && j != 0x10 && j != 0x40 && j != 0x50 && j != 0x76)
42  return 0;
43  if (j)
44  valid++;
45  i += j;
46  }
47  if (valid > 10)
48  return AVPROBE_SCORE_MAX;
49  if (valid > 2)
50  return AVPROBE_SCORE_EXTENSION - 1;
51  return 0;
52 }
53 
54 static int read_header(AVFormatContext *s)
55 {
56  AVStream* st;
57 
59  if (!st)
60  return AVERROR(ENOMEM);
61 
64  st->codecpar->sample_rate=8000;
65  st->codecpar->block_align = 16;
66  st->codecpar->channels=1;
67 
68  avpriv_set_pts_info(st, 64, 1, 100);
69  return 0;
70 }
71 
72 static int read_packet(AVFormatContext *s,
73  AVPacket *pkt)
74 {
75  AVIOContext *pb = s->pb;
76  PutBitContext pbo;
77  uint16_t buf[8 * MAX_FRAME_SIZE + 2];
78  int packet_size;
79  uint16_t* src=buf;
80  int i, j, ret;
81  int64_t pos= avio_tell(pb);
82 
83  if(avio_feof(pb))
84  return AVERROR_EOF;
85 
86  avio_rl16(pb); // sync word
87  packet_size = avio_rl16(pb) / 8;
88  if(packet_size > MAX_FRAME_SIZE)
89  return AVERROR_INVALIDDATA;
90 
91  ret = avio_read(pb, (uint8_t*)buf, (8 * packet_size) * sizeof(uint16_t));
92  if(ret<0)
93  return ret;
94  if(ret != 8 * packet_size * sizeof(uint16_t))
95  return AVERROR(EIO);
96 
97  if ((ret = av_new_packet(pkt, packet_size)) < 0)
98  return ret;
99 
100  init_put_bits(&pbo, pkt->data, packet_size);
101  for(j=0; j < packet_size; j++)
102  for(i=0; i<8;i++)
103  put_bits(&pbo,1, AV_RL16(src++) == BIT_1 ? 1 : 0);
104 
105  flush_put_bits(&pbo);
106 
107  pkt->duration=1;
108  pkt->pos = pos;
109  return 0;
110 }
111 
113  .name = "bit",
114  .long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
115  .read_probe = probe,
116  .read_header = read_header,
117  .read_packet = read_packet,
118  .extensions = "bit",
119 };
120 #endif
121 
122 #if CONFIG_BIT_MUXER
123 static int write_header(AVFormatContext *s)
124 {
125  AVCodecParameters *par = s->streams[0]->codecpar;
126 
127  if ((par->codec_id != AV_CODEC_ID_G729) || par->channels != 1) {
129  "only codec g729 with 1 channel is supported by this format\n");
130  return AVERROR(EINVAL);
131  }
132 
133  par->bits_per_coded_sample = 16;
134  par->block_align = (par->bits_per_coded_sample * par->channels) >> 3;
135 
136  return 0;
137 }
138 
140 {
141  AVIOContext *pb = s->pb;
142  GetBitContext gb;
143  int i;
144 
145  if (pkt->size != 10)
146  return AVERROR(EINVAL);
147 
148  avio_wl16(pb, SYNC_WORD);
149  avio_wl16(pb, 8 * pkt->size);
150 
151  init_get_bits(&gb, pkt->data, 8 * pkt->size);
152  for (i = 0; i < 8 * pkt->size; i++)
153  avio_wl16(pb, get_bits1(&gb) ? BIT_1 : BIT_0);
154 
155  return 0;
156 }
157 
159  .name = "bit",
160  .long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
161  .mime_type = "audio/bit",
162  .extensions = "bit",
163  .audio_codec = AV_CODEC_ID_G729,
164  .video_codec = AV_CODEC_ID_NONE,
165  .write_header = write_header,
166  .write_packet = write_packet,
167 };
168 #endif
AVOutputFormat::name
const char * name
Definition: avformat.h:496
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
ff_bit_muxer
const AVOutputFormat ff_bit_muxer
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
AVCodecParameters
This struct describes the properties of an encoded stream.
Definition: codec_par.h:52
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
init_put_bits
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:61
put_bits
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:220
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
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
init_get_bits
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:660
avio_wl16
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:451
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
BIT_1
#define BIT_1
Definition: bit.c:30
GetBitContext
Definition: get_bits.h:62
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:486
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:726
MAX_FRAME_SIZE
#define MAX_FRAME_SIZE
Definition: bit.c:26
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
AVInputFormat
Definition: avformat.h:626
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
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
get_bits.h
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
PutBitContext
Definition: put_bits.h:49
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
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
NULL
#define NULL
Definition: coverity.c:32
get_bits1
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:499
src
#define src
Definition: vp8dsp.c:255
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
SYNC_WORD
#define SYNC_WORD
Definition: bit.c:28
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
ff_bit_demuxer
const AVInputFormat ff_bit_demuxer
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
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
write_packet
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:731
i
int i
Definition: input.c:406
AV_CODEC_ID_NONE
@ AV_CODEC_ID_NONE
Definition: codec_id.h:48
AVOutputFormat
Definition: avformat.h:495
AVCodecParameters::block_align
int block_align
Audio only.
Definition: codec_par.h:177
ret
ret
Definition: filter_design.txt:187
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
AVStream
Stream structure.
Definition: avformat.h:845
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
probe
static int probe(const AVProbeData *p)
Definition: act.c:37
AV_CODEC_ID_G729
@ AV_CODEC_ID_G729
Definition: codec_id.h:475
avio_read
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
Definition: aviobuf.c:625
BIT_0
#define BIT_0
Definition: bit.c:29
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
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:102
flush_put_bits
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:142
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
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
write_header
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:347
put_bits.h
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:360