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libavformat
act.c
Go to the documentation of this file.
1
/*
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* ACT file format demuxer
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* Copyright (c) 2007-2008 Vladimir Voroshilov
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*
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* This file is part of FFmpeg.
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*
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* 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
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
19
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "
avformat.h
"
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#include "
riff.h
"
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#include "
internal.h
"
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#include "
libavcodec/get_bits.h
"
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#define CHUNK_SIZE 512
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#define RIFF_TAG MKTAG('R','I','F','F')
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#define WAVE_TAG MKTAG('W','A','V','E')
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typedef
struct
{
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int
bytes_left_in_chunk
;
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uint8_t
audio_buffer[22];
///< temporary buffer for ACT frame
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char
second_packet
;
///< 1 - if temporary buffer contains valid (second) G.729 packet
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}
ACTContext
;
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static
int
probe
(
AVProbeData
*p)
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{
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int
i;
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if
((
AV_RL32
(&p->
buf
[0]) !=
RIFF_TAG
) ||
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(
AV_RL32
(&p->
buf
[8]) !=
WAVE_TAG
) ||
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(
AV_RL32
(&p->
buf
[16]) != 16))
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return
0;
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//We can't be sure that this is ACT and not regular WAV
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if
(p->
buf_size
<512)
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return
0;
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for
(i=44; i<256; i++)
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if
(p->
buf
[i])
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return
0;
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if
(p->
buf
[256]!=0x84)
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return
0;
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for
(i=264; i<512; i++)
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if
(p->
buf
[i])
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return
0;
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return
AVPROBE_SCORE_MAX
;
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}
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static
int
read_header
(
AVFormatContext
*
s
)
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{
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ACTContext
* ctx = s->
priv_data
;
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AVIOContext
*pb = s->
pb
;
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int
size
;
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AVStream
* st;
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int
min
,sec,msec;
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st =
avformat_new_stream
(s,
NULL
);
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if
(!st)
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return
AVERROR
(ENOMEM);
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avio_skip
(pb, 16);
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size=
avio_rl32
(pb);
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ff_get_wav_header
(pb, st->
codec
, size, 0);
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/*
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8000Hz (Fine-rec) file format has 10 bytes long
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packets with 10ms of sound data in them
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*/
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if
(st->
codec
->
sample_rate
!= 8000) {
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av_log
(s,
AV_LOG_ERROR
,
"Sample rate %d is not supported.\n"
, st->
codec
->
sample_rate
);
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return
AVERROR_INVALIDDATA
;
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}
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st->
codec
->
frame_size
=80;
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st->
codec
->
channels
=1;
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avpriv_set_pts_info
(st, 64, 1, 100);
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st->
codec
->
codec_id
=
AV_CODEC_ID_G729
;
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avio_seek
(pb, 257, SEEK_SET);
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msec=
avio_rl16
(pb);
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sec=
avio_r8
(pb);
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min=
avio_rl32
(pb);
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st->
duration
=
av_rescale
(1000*(min*60+sec)+msec, st->
codec
->
sample_rate
, 1000 * st->
codec
->
frame_size
);
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ctx->
bytes_left_in_chunk
=
CHUNK_SIZE
;
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avio_seek
(pb, 512, SEEK_SET);
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return
0;
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}
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static
int
read_packet
(
AVFormatContext
*
s
,
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AVPacket
*
pkt
)
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{
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ACTContext
*ctx = s->
priv_data
;
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AVIOContext
*pb = s->
pb
;
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int
ret
;
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int
frame_size
=s->
streams
[0]->
codec
->
sample_rate
==8000?10:22;
117
118
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if
(s->
streams
[0]->
codec
->
sample_rate
==8000)
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ret=
av_new_packet
(pkt, 10);
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else
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ret=
av_new_packet
(pkt, 11);
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if
(ret)
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return
ret
;
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if
(s->
streams
[0]->
codec
->
sample_rate
==4400 && !ctx->
second_packet
)
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{
129
ret =
avio_read
(pb, ctx->
audio_buffer
, frame_size);
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131
if
(ret<0)
132
return
ret
;
133
if
(ret!=frame_size)
134
return
AVERROR
(EIO);
135
136
pkt->
data
[0]=ctx->
audio_buffer
[11];
137
pkt->
data
[1]=ctx->
audio_buffer
[0];
138
pkt->
data
[2]=ctx->
audio_buffer
[12];
139
pkt->
data
[3]=ctx->
audio_buffer
[1];
140
pkt->
data
[4]=ctx->
audio_buffer
[13];
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pkt->
data
[5]=ctx->
audio_buffer
[2];
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pkt->
data
[6]=ctx->
audio_buffer
[14];
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pkt->
data
[7]=ctx->
audio_buffer
[3];
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pkt->
data
[8]=ctx->
audio_buffer
[15];
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pkt->
data
[9]=ctx->
audio_buffer
[4];
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pkt->
data
[10]=ctx->
audio_buffer
[16];
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148
ctx->
second_packet
=1;
149
}
150
else
if
(s->
streams
[0]->
codec
->
sample_rate
==4400 && ctx->
second_packet
)
151
{
152
pkt->
data
[0]=ctx->
audio_buffer
[5];
153
pkt->
data
[1]=ctx->
audio_buffer
[17];
154
pkt->
data
[2]=ctx->
audio_buffer
[6];
155
pkt->
data
[3]=ctx->
audio_buffer
[18];
156
pkt->
data
[4]=ctx->
audio_buffer
[7];
157
pkt->
data
[5]=ctx->
audio_buffer
[19];
158
pkt->
data
[6]=ctx->
audio_buffer
[8];
159
pkt->
data
[7]=ctx->
audio_buffer
[20];
160
pkt->
data
[8]=ctx->
audio_buffer
[9];
161
pkt->
data
[9]=ctx->
audio_buffer
[21];
162
pkt->
data
[10]=ctx->
audio_buffer
[10];
163
164
ctx->
second_packet
=0;
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}
166
else
// 8000 Hz
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{
168
ret =
avio_read
(pb, ctx->
audio_buffer
, frame_size);
169
170
if
(ret<0)
171
return
ret
;
172
if
(ret!=frame_size)
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return
AVERROR
(EIO);
174
175
pkt->
data
[0]=ctx->
audio_buffer
[5];
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pkt->
data
[1]=ctx->
audio_buffer
[0];
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pkt->
data
[2]=ctx->
audio_buffer
[6];
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pkt->
data
[3]=ctx->
audio_buffer
[1];
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pkt->
data
[4]=ctx->
audio_buffer
[7];
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pkt->
data
[5]=ctx->
audio_buffer
[2];
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pkt->
data
[6]=ctx->
audio_buffer
[8];
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pkt->
data
[7]=ctx->
audio_buffer
[3];
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pkt->
data
[8]=ctx->
audio_buffer
[9];
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pkt->
data
[9]=ctx->
audio_buffer
[4];
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}
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ctx->
bytes_left_in_chunk
-=
frame_size
;
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189
if
(ctx->
bytes_left_in_chunk
< frame_size)
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{
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avio_skip
(pb, ctx->
bytes_left_in_chunk
);
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ctx->
bytes_left_in_chunk
=
CHUNK_SIZE
;
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}
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pkt->
duration
=1;
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return
ret
;
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}
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AVInputFormat
ff_act_demuxer
= {
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.
name
=
"act"
,
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.long_name =
"ACT Voice file format"
,
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.priv_data_size =
sizeof
(
ACTContext
),
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.
read_probe
=
probe
,
205
.
read_header
=
read_header
,
206
.
read_packet
=
read_packet
,
207
};
Generated on Sun Mar 8 2015 02:35:08 for FFmpeg by
1.8.2