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 <string.h>
30 #include "libavutil/intmath.h"
31 #include "mpegaudiodsp.h"
32
33 #include "mpc.h"
34 #include "mpcdata.h"
35
36 /**
37 * Process decoded Musepack data and produce PCM
38 */
mpc_synth(MPCContext *c, int16_t **out, int channels)39 static void mpc_synth(MPCContext *c, int16_t **out, int channels)
40 {
41 int dither_state = 0;
42 int i, ch;
43
44 for(ch = 0; ch < channels; ch++){
45 for(i = 0; i < SAMPLES_PER_BAND; i++) {
46 ff_mpa_synth_filter_fixed(&c->mpadsp,
47 c->synth_buf[ch], &(c->synth_buf_offset[ch]),
48 ff_mpa_synth_window_fixed, &dither_state,
49 out[ch] + 32 * i, 1,
50 c->sb_samples[ch][i]);
51 }
52 }
53 }
54
ff_mpc_dequantize_and_synth(MPCContext * c, int maxband, int16_t **out, int channels)55 void ff_mpc_dequantize_and_synth(MPCContext * c, int maxband, int16_t **out,
56 int channels)
57 {
58 int i, j, ch;
59 Band *bands = c->bands;
60 int off;
61 float mul;
62
63 /* dequantize */
64 memset(c->sb_samples, 0, sizeof(c->sb_samples));
65 off = 0;
66 for(i = 0; i <= maxband; i++, off += SAMPLES_PER_BAND){
67 for(ch = 0; ch < 2; ch++){
68 if(bands[i].res[ch]){
69 j = 0;
70 mul = (mpc_CC+1)[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][0] & 0xFF];
71 for(; j < 12; j++)
72 c->sb_samples[ch][j][i] = av_clipf(mul * c->Q[ch][j + off], INT32_MIN, INT32_MAX);
73 mul = (mpc_CC+1)[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][1] & 0xFF];
74 for(; j < 24; j++)
75 c->sb_samples[ch][j][i] = av_clipf(mul * c->Q[ch][j + off], INT32_MIN, INT32_MAX);
76 mul = (mpc_CC+1)[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][2] & 0xFF];
77 for(; j < 36; j++)
78 c->sb_samples[ch][j][i] = av_clipf(mul * c->Q[ch][j + off], INT32_MIN, INT32_MAX);
79 }
80 }
81 if(bands[i].msf){
82 unsigned t1, t2;
83 for(j = 0; j < SAMPLES_PER_BAND; j++){
84 t1 = c->sb_samples[0][j][i];
85 t2 = c->sb_samples[1][j][i];
86 c->sb_samples[0][j][i] = t1 + t2;
87 c->sb_samples[1][j][i] = t1 - t2;
88 }
89 }
90 }
91
92 mpc_synth(c, out, channels);
93 }
94