Statistics
| Branch: | Revision:

ffmpeg / libavcodec / mpc.c @ 2912e87a

History | View | Annotate | Download (3.19 KB)

1
/*
2
 * Musepack decoder core
3
 * Copyright (c) 2006 Konstantin Shishkov
4
 *
5
 * This file is part of Libav.
6
 *
7
 * Libav 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
 * Libav 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 Libav; 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 "avcodec.h"
30
#include "get_bits.h"
31
#include "dsputil.h"
32
#include "mpegaudio.h"
33

    
34
#include "mpc.h"
35
#include "mpcdata.h"
36

    
37
void ff_mpc_init(void)
38
{
39
    ff_mpa_synth_init(ff_mpa_synth_window);
40
}
41

    
42
/**
43
 * Process decoded Musepack data and produce PCM
44
 */
45
static void mpc_synth(MPCContext *c, int16_t *out, int channels)
46
{
47
    int dither_state = 0;
48
    int i, ch;
49
    OUT_INT samples[MPA_MAX_CHANNELS * MPA_FRAME_SIZE], *samples_ptr;
50

    
51
    for(ch = 0;  ch < channels; ch++){
52
        samples_ptr = samples + ch;
53
        for(i = 0; i < SAMPLES_PER_BAND; i++) {
54
            ff_mpa_synth_filter(c->synth_buf[ch], &(c->synth_buf_offset[ch]),
55
                                ff_mpa_synth_window, &dither_state,
56
                                samples_ptr, channels,
57
                                c->sb_samples[ch][i]);
58
            samples_ptr += 32 * channels;
59
        }
60
    }
61
    for(i = 0; i < MPC_FRAME_SIZE*channels; i++)
62
        *out++=samples[i];
63
}
64

    
65
void ff_mpc_dequantize_and_synth(MPCContext * c, int maxband, void *data, int channels)
66
{
67
    int i, j, ch;
68
    Band *bands = c->bands;
69
    int off;
70
    float mul;
71

    
72
    /* dequantize */
73
    memset(c->sb_samples, 0, sizeof(c->sb_samples));
74
    off = 0;
75
    for(i = 0; i <= maxband; i++, off += SAMPLES_PER_BAND){
76
        for(ch = 0; ch < 2; ch++){
77
            if(bands[i].res[ch]){
78
                j = 0;
79
                mul = mpc_CC[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][0]];
80
                for(; j < 12; j++)
81
                    c->sb_samples[ch][j][i] = mul * c->Q[ch][j + off];
82
                mul = mpc_CC[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][1]];
83
                for(; j < 24; j++)
84
                    c->sb_samples[ch][j][i] = mul * c->Q[ch][j + off];
85
                mul = mpc_CC[bands[i].res[ch]] * mpc_SCF[bands[i].scf_idx[ch][2]];
86
                for(; j < 36; j++)
87
                    c->sb_samples[ch][j][i] = mul * c->Q[ch][j + off];
88
            }
89
        }
90
        if(bands[i].msf){
91
            int t1, t2;
92
            for(j = 0; j < SAMPLES_PER_BAND; j++){
93
                t1 = c->sb_samples[0][j][i];
94
                t2 = c->sb_samples[1][j][i];
95
                c->sb_samples[0][j][i] = t1 + t2;
96
                c->sb_samples[1][j][i] = t1 - t2;
97
            }
98
        }
99
    }
100

    
101
    mpc_synth(c, data, channels);
102
}