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libavformat
apc.c
Go to the documentation of this file.
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/*
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* CRYO APC audio format demuxer
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* Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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 <string.h>
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#include "
avformat.h
"
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static
int
apc_probe
(
AVProbeData
*p)
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{
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if
(!strncmp(p->
buf
,
"CRYO_APC"
, 8))
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return
AVPROBE_SCORE_MAX
;
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return
0;
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}
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static
int
apc_read_header
(
AVFormatContext
*s,
AVFormatParameters
*ap)
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{
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AVIOContext
*pb = s->
pb
;
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AVStream
*st;
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avio_rl32
(pb);
/* CRYO */
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avio_rl32
(pb);
/* _APC */
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avio_rl32
(pb);
/* 1.20 */
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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_type
=
AVMEDIA_TYPE_AUDIO
;
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st->
codec
->
codec_id
=
CODEC_ID_ADPCM_IMA_WS
;
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avio_rl32
(pb);
/* number of samples */
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st->
codec
->
sample_rate
=
avio_rl32
(pb);
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st->
codec
->
extradata_size
= 2 * 4;
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st->
codec
->
extradata
=
av_malloc
(st->
codec
->
extradata_size
+
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FF_INPUT_BUFFER_PADDING_SIZE
);
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if
(!st->
codec
->
extradata
)
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return
AVERROR
(ENOMEM);
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/* initial predictor values for adpcm decoder */
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avio_read
(pb, st->
codec
->
extradata
, 2 * 4);
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st->
codec
->
channels
= 1;
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if
(
avio_rl32
(pb))
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st->
codec
->
channels
= 2;
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st->
codec
->
bits_per_coded_sample
= 4;
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st->
codec
->
bit_rate
= st->
codec
->
bits_per_coded_sample
* st->
codec
->
channels
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* st->
codec
->
sample_rate
;
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st->
codec
->
block_align
= 1;
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return
0;
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}
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#define MAX_READ_SIZE 4096
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static
int
apc_read_packet
(
AVFormatContext
*s,
AVPacket
*pkt)
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{
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if
(
av_get_packet
(s->
pb
, pkt,
MAX_READ_SIZE
) <= 0)
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return
AVERROR
(EIO);
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pkt->
stream_index
= 0;
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return
0;
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}
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AVInputFormat
ff_apc_demuxer
= {
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.
name
=
"apc"
,
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.long_name =
NULL_IF_CONFIG_SMALL
(
"CRYO APC format"
),
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.read_probe =
apc_probe
,
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.read_header =
apc_read_header
,
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.read_packet =
apc_read_packet
,
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};