Statistics
| Branch: | Revision:

ffmpeg / libavcodec / nellymoserdec.c @ 26f548bb

History | View | Annotate | Download (6.26 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
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 "libavutil/audioconvert.h"
38
#include "avcodec.h"
39
#include "dsputil.h"
40
#include "fft.h"
41
#include "fmtconvert.h"
42

    
43
#define ALT_BITSTREAM_READER_LE
44
#include "get_bits.h"
45

    
46

    
47
typedef struct NellyMoserDecodeContext {
48
    AVCodecContext* avctx;
49
    DECLARE_ALIGNED(16, float,float_buf)[NELLY_SAMPLES];
50
    float           state[128];
51
    AVLFG           random_state;
52
    GetBitContext   gb;
53
    float           scale_bias;
54
    DSPContext      dsp;
55
    FFTContext      imdct_ctx;
56
    FmtConvertContext fmt_conv;
57
    DECLARE_ALIGNED(16, float,imdct_out)[NELLY_BUF_LEN * 2];
58
} NellyMoserDecodeContext;
59

    
60
static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in)
61
{
62
    int bot, top;
63

    
64
    bot = 0;
65
    top = NELLY_BUF_LEN-1;
66

    
67
    while (bot < NELLY_BUF_LEN) {
68
        audio[bot] = a_in [bot]*ff_sine_128[bot]
69
                    +state[bot]*ff_sine_128[top];
70

    
71
        bot++;
72
        top--;
73
    }
74
    memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);
75
}
76

    
77
static void nelly_decode_block(NellyMoserDecodeContext *s,
78
                               const unsigned char block[NELLY_BLOCK_LEN],
79
                               float audio[NELLY_SAMPLES])
80
{
81
    int i,j;
82
    float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
83
    float *aptr, *bptr, *pptr, val, pval;
84
    int bits[NELLY_BUF_LEN];
85
    unsigned char v;
86

    
87
    init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
88

    
89
    bptr = buf;
90
    pptr = pows;
91
    val = ff_nelly_init_table[get_bits(&s->gb, 6)];
92
    for (i=0 ; i<NELLY_BANDS ; i++) {
93
        if (i > 0)
94
            val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
95
        pval = -pow(2, val/2048) * s->scale_bias;
96
        for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
97
            *bptr++ = val;
98
            *pptr++ = pval;
99
        }
100

    
101
    }
102

    
103
    ff_nelly_get_sample_bits(buf, bits);
104

    
105
    for (i = 0; i < 2; i++) {
106
        aptr = audio + i * NELLY_BUF_LEN;
107

    
108
        init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
109
        skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
110

    
111
        for (j = 0; j < NELLY_FILL_LEN; j++) {
112
            if (bits[j] <= 0) {
113
                aptr[j] = M_SQRT1_2*pows[j];
114
                if (av_lfg_get(&s->random_state) & 1)
115
                    aptr[j] *= -1.0;
116
            } else {
117
                v = get_bits(&s->gb, bits[j]);
118
                aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
119
            }
120
        }
121
        memset(&aptr[NELLY_FILL_LEN], 0,
122
               (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
123

    
124
        s->imdct_ctx.imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);
125
        /* XXX: overlapping and windowing should be part of a more
126
           generic imdct function */
127
        overlap_and_window(s, s->state, aptr, s->imdct_out);
128
    }
129
}
130

    
131
static av_cold int decode_init(AVCodecContext * avctx) {
132
    NellyMoserDecodeContext *s = avctx->priv_data;
133

    
134
    s->avctx = avctx;
135
    av_lfg_init(&s->random_state, 0);
136
    ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
137

    
138
    dsputil_init(&s->dsp, avctx);
139
    ff_fmt_convert_init(&s->fmt_conv, avctx);
140

    
141
    s->scale_bias = 1.0/(1*8);
142

    
143
    /* Generate overlap window */
144
    if (!ff_sine_128[127])
145
        ff_init_ff_sine_windows(7);
146

    
147
    avctx->sample_fmt = AV_SAMPLE_FMT_S16;
148
    avctx->channel_layout = AV_CH_LAYOUT_MONO;
149
    return 0;
150
}
151

    
152
static int decode_tag(AVCodecContext * avctx,
153
                      void *data, int *data_size,
154
                      AVPacket *avpkt) {
155
    const uint8_t *buf = avpkt->data;
156
    int buf_size = avpkt->size;
157
    NellyMoserDecodeContext *s = avctx->priv_data;
158
    int blocks, i;
159
    int16_t* samples;
160
    *data_size = 0;
161
    samples = (int16_t*)data;
162

    
163
    if (buf_size < avctx->block_align)
164
        return buf_size;
165

    
166
    if (buf_size % 64) {
167
        av_log(avctx, AV_LOG_ERROR, "Tag size %d.\n", buf_size);
168
        return buf_size;
169
    }
170
    blocks = buf_size / 64;
171
    /* Normal numbers of blocks for sample rates:
172
     *  8000 Hz - 1
173
     * 11025 Hz - 2
174
     * 16000 Hz - 3
175
     * 22050 Hz - 4
176
     * 44100 Hz - 8
177
     */
178

    
179
    for (i=0 ; i<blocks ; i++) {
180
        nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);
181
        s->fmt_conv.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);
182
        *data_size += NELLY_SAMPLES*sizeof(int16_t);
183
    }
184

    
185
    return buf_size;
186
}
187

    
188
static av_cold int decode_end(AVCodecContext * avctx) {
189
    NellyMoserDecodeContext *s = avctx->priv_data;
190

    
191
    ff_mdct_end(&s->imdct_ctx);
192
    return 0;
193
}
194

    
195
AVCodec ff_nellymoser_decoder = {
196
    "nellymoser",
197
    AVMEDIA_TYPE_AUDIO,
198
    CODEC_ID_NELLYMOSER,
199
    sizeof(NellyMoserDecodeContext),
200
    decode_init,
201
    NULL,
202
    decode_end,
203
    decode_tag,
204
    .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
205
};
206