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libavcodec
mpc.c
Go to the documentation of this file.
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/*
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* Musepack decoder core
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* Copyright (c) 2006 Konstantin Shishkov
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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
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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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/**
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* @file
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* Musepack decoder core
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* MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
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* divided into 32 subbands.
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*/
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#include "
libavutil/attributes.h
"
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#include "
avcodec.h
"
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#include "
get_bits.h
"
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#include "
mpegaudiodsp.h
"
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#include "
mpegaudio.h
"
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#include "
mpc.h
"
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#include "
mpcdata.h
"
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av_cold
void
ff_mpc_init
(
void
)
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{
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ff_mpa_synth_init_fixed
(
ff_mpa_synth_window_fixed
);
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}
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/**
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* Process decoded Musepack data and produce PCM
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*/
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static
void
mpc_synth
(
MPCContext
*
c
, int16_t **
out
,
int
channels)
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{
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int
dither_state = 0;
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int
i, ch;
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for
(ch = 0; ch < channels; ch++){
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for
(i = 0; i <
SAMPLES_PER_BAND
; i++) {
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ff_mpa_synth_filter_fixed
(&c->
mpadsp
,
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c->
synth_buf
[ch], &(c->
synth_buf_offset
[ch]),
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ff_mpa_synth_window_fixed
, &dither_state,
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out[ch] + 32 * i, 1,
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c->
sb_samples
[ch][i]);
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}
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}
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}
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void
ff_mpc_dequantize_and_synth
(
MPCContext
*
c
,
int
maxband, int16_t **
out
,
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int
channels)
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{
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int
i, j, ch;
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Band
*bands = c->
bands
;
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int
off
;
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float
mul;
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/* dequantize */
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memset(c->
sb_samples
, 0,
sizeof
(c->
sb_samples
));
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off = 0;
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for
(i = 0; i <= maxband; i++, off +=
SAMPLES_PER_BAND
){
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for
(ch = 0; ch < 2; ch++){
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if
(bands[i].
res
[ch]){
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j = 0;
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mul = (
mpc_CC
+1)[bands[i].
res
[ch]] *
mpc_SCF
[bands[i].scf_idx[ch][0] & 0xFF];
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for
(; j < 12; j++)
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c->
sb_samples
[ch][j][i] = mul * c->
Q
[ch][j + off];
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mul = (
mpc_CC
+1)[bands[i].
res
[ch]] *
mpc_SCF
[bands[i].
scf_idx
[ch][1] & 0xFF];
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for
(; j < 24; j++)
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c->
sb_samples
[ch][j][i] = mul * c->
Q
[ch][j + off];
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mul = (
mpc_CC
+1)[bands[i].
res
[ch]] *
mpc_SCF
[bands[i].
scf_idx
[ch][2] & 0xFF];
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for
(; j < 36; j++)
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c->
sb_samples
[ch][j][i] = mul * c->
Q
[ch][j + off];
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}
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}
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if
(bands[i].msf){
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int
t1
,
t2
;
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for
(j = 0; j <
SAMPLES_PER_BAND
; j++){
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t1 = c->
sb_samples
[0][j][i];
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t2 = c->
sb_samples
[1][j][i];
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c->
sb_samples
[0][j][i] = t1 +
t2
;
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c->
sb_samples
[1][j][i] = t1 -
t2
;
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}
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}
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}
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mpc_synth
(c, out, channels);
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}
Generated on Wed Jul 10 2013 23:48:01 for FFmpeg by
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