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mpc.c
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1 /*
2  * Musepack decoder core
3  * Copyright (c) 2006 Konstantin Shishkov
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 
22 /**
23  * @file
24  * Musepack decoder core
25  * MPEG Audio Layer 1/2 -like codec with frames of 1152 samples
26  * divided into 32 subbands.
27  */
28 
29 #include "libavutil/attributes.h"
30 #include "avcodec.h"
31 #include "get_bits.h"
32 #include "mpegaudiodsp.h"
33 #include "mpegaudio.h"
34 
35 #include "mpc.h"
36 #include "mpcdata.h"
37 
38 av_cold void ff_mpc_init(void)
39 {
41 }
42 
43 /**
44  * Process decoded Musepack data and produce PCM
45  */
46 static void mpc_synth(MPCContext *c, int16_t **out, int channels)
47 {
48  int dither_state = 0;
49  int i, ch;
50 
51  for(ch = 0; ch < channels; ch++){
52  for(i = 0; i < SAMPLES_PER_BAND; i++) {
54  c->synth_buf[ch], &(c->synth_buf_offset[ch]),
55  ff_mpa_synth_window_fixed, &dither_state,
56  out[ch] + 32 * i, 1,
57  c->sb_samples[ch][i]);
58  }
59  }
60 }
61 
62 void ff_mpc_dequantize_and_synth(MPCContext * c, int maxband, int16_t **out,
63  int channels)
64 {
65  int i, j, ch;
66  Band *bands = c->bands;
67  int off;
68  float mul;
69 
70  /* dequantize */
71  memset(c->sb_samples, 0, sizeof(c->sb_samples));
72  off = 0;
73  for(i = 0; i <= maxband; i++, off += SAMPLES_PER_BAND){
74  for(ch = 0; ch < 2; ch++){
75  if(bands[i].res[ch]){
76  j = 0;
77  mul = (mpc_CC+1)[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][0] & 0xFF];
78  for(; j < 12; j++)
79  c->sb_samples[ch][j][i] = mul * c->Q[ch][j + off];
80  mul = (mpc_CC+1)[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][1] & 0xFF];
81  for(; j < 24; j++)
82  c->sb_samples[ch][j][i] = mul * c->Q[ch][j + off];
83  mul = (mpc_CC+1)[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][2] & 0xFF];
84  for(; j < 36; j++)
85  c->sb_samples[ch][j][i] = mul * c->Q[ch][j + off];
86  }
87  }
88  if(bands[i].msf){
89  int t1, t2;
90  for(j = 0; j < SAMPLES_PER_BAND; j++){
91  t1 = c->sb_samples[0][j][i];
92  t2 = c->sb_samples[1][j][i];
93  c->sb_samples[0][j][i] = t1 + t2;
94  c->sb_samples[1][j][i] = t1 - t2;
95  }
96  }
97  }
98 
99  mpc_synth(c, out, channels);
100 }