Statistics
| Branch: | Revision:

ffmpeg / libavcodec / nellymoserdec.c @ 72415b2a

History | View | Annotate | Download (6.48 KB)

1
/*
2
 * NellyMoser audio decoder
3
 * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5,
4
 *                    539459aeb7d425140b62a3ec7dbf6dc8e408a306, and
5
 *                    520e17cd55896441042b14df2566a6eb610ed444
6
 * Copyright (c) 2007 Loic Minier <lool at dooz.org>
7
 *                    Benjamin Larsson
8
 *
9
 * Permission is hereby granted, free of charge, to any person obtaining a
10
 * copy of this software and associated documentation files (the "Software"),
11
 * to deal in the Software without restriction, including without limitation
12
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13
 * and/or sell copies of the Software, and to permit persons to whom the
14
 * Software is furnished to do so, subject to the following conditions:
15
 *
16
 * The above copyright notice and this permission notice shall be included in
17
 * all copies or substantial portions of the Software.
18
 *
19
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25
 * DEALINGS IN THE SOFTWARE.
26
 */
27

    
28
/**
29
 * @file libavcodec/nellymoserdec.c
30
 * The 3 alphanumeric copyright notices are md5summed they are from the original
31
 * implementors. The original code is available from http://code.google.com/p/nelly2pcm/
32
 */
33

    
34
#include "nellymoser.h"
35
#include "libavutil/lfg.h"
36
#include "libavutil/random_seed.h"
37
#include "avcodec.h"
38
#include "dsputil.h"
39
#include "fft.h"
40

    
41
#define ALT_BITSTREAM_READER_LE
42
#include "get_bits.h"
43

    
44

    
45
typedef struct NellyMoserDecodeContext {
46
    AVCodecContext* avctx;
47
    DECLARE_ALIGNED(16, float,float_buf)[NELLY_SAMPLES];
48
    float           state[128];
49
    AVLFG           random_state;
50
    GetBitContext   gb;
51
    int             add_bias;
52
    float           scale_bias;
53
    DSPContext      dsp;
54
    FFTContext      imdct_ctx;
55
    DECLARE_ALIGNED(16, float,imdct_out)[NELLY_BUF_LEN * 2];
56
} NellyMoserDecodeContext;
57

    
58
static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in)
59
{
60
    int bot, top;
61

    
62
    bot = 0;
63
    top = NELLY_BUF_LEN-1;
64

    
65
    while (bot < NELLY_BUF_LEN) {
66
        audio[bot] = a_in [bot]*ff_sine_128[bot]
67
                    +state[bot]*ff_sine_128[top] + s->add_bias;
68

    
69
        bot++;
70
        top--;
71
    }
72
    memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);
73
}
74

    
75
static void nelly_decode_block(NellyMoserDecodeContext *s,
76
                               const unsigned char block[NELLY_BLOCK_LEN],
77
                               float audio[NELLY_SAMPLES])
78
{
79
    int i,j;
80
    float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
81
    float *aptr, *bptr, *pptr, val, pval;
82
    int bits[NELLY_BUF_LEN];
83
    unsigned char v;
84

    
85
    init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
86

    
87
    bptr = buf;
88
    pptr = pows;
89
    val = ff_nelly_init_table[get_bits(&s->gb, 6)];
90
    for (i=0 ; i<NELLY_BANDS ; i++) {
91
        if (i > 0)
92
            val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
93
        pval = -pow(2, val/2048) * s->scale_bias;
94
        for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
95
            *bptr++ = val;
96
            *pptr++ = pval;
97
        }
98

    
99
    }
100

    
101
    ff_nelly_get_sample_bits(buf, bits);
102

    
103
    for (i = 0; i < 2; i++) {
104
        aptr = audio + i * NELLY_BUF_LEN;
105

    
106
        init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
107
        skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
108

    
109
        for (j = 0; j < NELLY_FILL_LEN; j++) {
110
            if (bits[j] <= 0) {
111
                aptr[j] = M_SQRT1_2*pows[j];
112
                if (av_lfg_get(&s->random_state) & 1)
113
                    aptr[j] *= -1.0;
114
            } else {
115
                v = get_bits(&s->gb, bits[j]);
116
                aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
117
            }
118
        }
119
        memset(&aptr[NELLY_FILL_LEN], 0,
120
               (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
121

    
122
        ff_imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);
123
        /* XXX: overlapping and windowing should be part of a more
124
           generic imdct function */
125
        overlap_and_window(s, s->state, aptr, s->imdct_out);
126
    }
127
}
128

    
129
static av_cold int decode_init(AVCodecContext * avctx) {
130
    NellyMoserDecodeContext *s = avctx->priv_data;
131

    
132
    s->avctx = avctx;
133
    av_lfg_init(&s->random_state, 0);
134
    ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
135

    
136
    dsputil_init(&s->dsp, avctx);
137

    
138
    if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
139
        s->add_bias = 385;
140
        s->scale_bias = 1.0/(8*32768);
141
    } else {
142
        s->add_bias = 0;
143
        s->scale_bias = 1.0/(1*8);
144
    }
145

    
146
    /* Generate overlap window */
147
    if (!ff_sine_128[127])
148
        ff_init_ff_sine_windows(7);
149

    
150
    avctx->sample_fmt = SAMPLE_FMT_S16;
151
    avctx->channel_layout = CH_LAYOUT_MONO;
152
    return 0;
153
}
154

    
155
static int decode_tag(AVCodecContext * avctx,
156
                      void *data, int *data_size,
157
                      AVPacket *avpkt) {
158
    const uint8_t *buf = avpkt->data;
159
    int buf_size = avpkt->size;
160
    NellyMoserDecodeContext *s = avctx->priv_data;
161
    int blocks, i;
162
    int16_t* samples;
163
    *data_size = 0;
164
    samples = (int16_t*)data;
165

    
166
    if (buf_size < avctx->block_align)
167
        return buf_size;
168

    
169
    switch (buf_size) {
170
        case 64:    // 8000Hz
171
            blocks = 1; break;
172
        case 128:   // 11025Hz
173
            blocks = 2; break;
174
        case 192:   // 16000Hz
175
            blocks = 3; break;
176
        case 256:   // 22050Hz
177
            blocks = 4; break;
178
        case 512:   // 44100Hz
179
            blocks = 8; break;
180
        default:
181
            av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size);
182
            return buf_size;
183
    }
184

    
185
    for (i=0 ; i<blocks ; i++) {
186
        nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);
187
        s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);
188
        *data_size += NELLY_SAMPLES*sizeof(int16_t);
189
    }
190

    
191
    return buf_size;
192
}
193

    
194
static av_cold int decode_end(AVCodecContext * avctx) {
195
    NellyMoserDecodeContext *s = avctx->priv_data;
196

    
197
    ff_mdct_end(&s->imdct_ctx);
198
    return 0;
199
}
200

    
201
AVCodec nellymoser_decoder = {
202
    "nellymoser",
203
    AVMEDIA_TYPE_AUDIO,
204
    CODEC_ID_NELLYMOSER,
205
    sizeof(NellyMoserDecodeContext),
206
    decode_init,
207
    NULL,
208
    decode_end,
209
    decode_tag,
210
    .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
211
};
212