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
38av_cold void ff_mpc_init(void)
39{
40    ff_mpa_synth_init_fixed(ff_mpa_synth_window_fixed);
41}
42
43/**
44 * Process decoded Musepack data and produce PCM
45 */
46static 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++) {
53            ff_mpa_synth_filter_fixed(&c->mpadsp,
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
62void 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}
101