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libavformat
ilbc.c
Go to the documentation of this file.
1
/*
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* iLBC storage file format
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* Copyright (c) 2012 Martin Storsjo
4
*
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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
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* modify it under the terms of the GNU Lesser General Public
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* 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
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* 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 "
internal.h
"
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static
const
char
mode20_header
[] =
"#!iLBC20\n"
;
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static
const
char
mode30_header
[] =
"#!iLBC30\n"
;
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static
int
ilbc_write_header
(
AVFormatContext
*s)
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{
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AVIOContext
*pb = s->
pb
;
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AVCodecContext
*enc;
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if
(s->
nb_streams
!= 1) {
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av_log
(s,
AV_LOG_ERROR
,
"Unsupported number of streams\n"
);
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return
AVERROR
(EINVAL);
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}
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enc = s->
streams
[0]->
codec
;
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if
(enc->
codec_id
!=
AV_CODEC_ID_ILBC
) {
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av_log
(s,
AV_LOG_ERROR
,
"Unsupported codec\n"
);
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return
AVERROR
(EINVAL);
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}
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if
(enc->
block_align
== 50) {
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avio_write
(pb,
mode30_header
,
sizeof
(
mode30_header
) - 1);
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}
else
if
(enc->
block_align
== 38) {
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avio_write
(pb,
mode20_header
,
sizeof
(
mode20_header
) - 1);
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}
else
{
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av_log
(s,
AV_LOG_ERROR
,
"Unsupported mode\n"
);
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return
AVERROR
(EINVAL);
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}
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avio_flush
(pb);
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return
0;
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}
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static
int
ilbc_write_packet
(
AVFormatContext
*s,
AVPacket
*
pkt
)
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{
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avio_write
(s->
pb
, pkt->
data
, pkt->
size
);
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avio_flush
(s->
pb
);
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return
0;
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}
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static
int
ilbc_probe
(
AVProbeData
*p)
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{
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// Only check for "#!iLBC" which matches both formats
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if
(!memcmp(p->
buf
,
mode20_header
, 6))
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return
AVPROBE_SCORE_MAX
;
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else
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return
0;
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}
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static
int
ilbc_read_header
(
AVFormatContext
*s)
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{
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AVIOContext
*pb = s->
pb
;
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AVStream
*st;
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uint8_t
header[9];
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avio_read
(pb, header, 9);
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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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st->
codec
->
codec_id
=
AV_CODEC_ID_ILBC
;
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st->
codec
->
sample_rate
= 8000;
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st->
codec
->
channels
= 1;
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st->
codec
->
codec_type
=
AVMEDIA_TYPE_AUDIO
;
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st->
start_time
= 0;
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avpriv_set_pts_info
(st, 64, 1, st->
codec
->
sample_rate
);
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if
(!memcmp(header,
mode20_header
,
sizeof
(
mode20_header
) - 1)) {
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st->
codec
->
block_align
= 38;
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st->
codec
->
bit_rate
= 15200;
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}
else
if
(!memcmp(header,
mode30_header
,
sizeof
(
mode30_header
) - 1)) {
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st->
codec
->
block_align
= 50;
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st->
codec
->
bit_rate
= 13333;
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}
else
{
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av_log
(s,
AV_LOG_ERROR
,
"Unrecognized iLBC file header\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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return
0;
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}
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static
int
ilbc_read_packet
(
AVFormatContext
*s,
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AVPacket
*
pkt
)
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{
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AVCodecContext
*enc = s->
streams
[0]->
codec
;
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int
ret;
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if
((ret =
av_new_packet
(pkt, enc->
block_align
)) < 0)
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return
ret;
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pkt->
stream_index
= 0;
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pkt->
pos
=
avio_tell
(s->
pb
);
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pkt->
duration
= enc->
block_align
== 38 ? 160 : 240;
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if
((ret =
avio_read
(s->
pb
, pkt->
data
, enc->
block_align
)) != enc->
block_align
) {
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av_free_packet
(pkt);
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return
ret < 0 ? ret :
AVERROR
(EIO);
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}
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return
0;
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}
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AVInputFormat
ff_ilbc_demuxer
= {
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.
name
=
"ilbc"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"iLBC storage"
),
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.read_probe =
ilbc_probe
,
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.read_header =
ilbc_read_header
,
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.read_packet =
ilbc_read_packet
,
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.flags =
AVFMT_GENERIC_INDEX
,
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};
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AVOutputFormat
ff_ilbc_muxer
= {
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.
name
=
"ilbc"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"iLBC storage"
),
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.mime_type =
"audio/iLBC"
,
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.extensions =
"lbc"
,
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.audio_codec =
AV_CODEC_ID_ILBC
,
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.write_header =
ilbc_write_header
,
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.write_packet =
ilbc_write_packet
,
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.flags =
AVFMT_NOTIMESTAMPS
,
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};
Generated on Sat May 25 2013 03:58:46 for FFmpeg by
1.8.2