Revision dbb0f96f

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libavcodec/atrac1.c
1
/*
2
 * Atrac 1 compatible decoder
3
 * Copyright (c) 2009 Maxim Poliakovski
4
 * Copyright (c) 2009 Benjamin Larsson
5
 *
6
 * This file is part of FFmpeg.
7
 *
8
 * FFmpeg is free software; you can redistribute it and/or
9
 * modify it under the terms of the GNU Lesser General Public
10
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * FFmpeg is distributed in the hope that it will be useful,
14
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16
 * Lesser General Public License for more details.
17
 *
18
 * You should have received a copy of the GNU Lesser General Public
19
 * License along with FFmpeg; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22

  
23
/**
24
 * @file libavcodec/atrac1.c
25
 * Atrac 1 compatible decoder.
26
 * This decoder handles raw ATRAC1 data.
27
 */
28

  
29
/* Many thanks to Tim Craig for all the help! */
30

  
31
#include <math.h>
32
#include <stddef.h>
33
#include <stdio.h>
34

  
35
#include "avcodec.h"
36
#include "get_bits.h"
37
#include "dsputil.h"
38

  
39
#include "atrac.h"
40
#include "atrac1data.h"
41

  
42
#define AT1_MAX_BFU      52                 ///< max number of block floating units in a sound unit
43
#define AT1_SU_SIZE      212                ///< number of bytes in a sound unit
44
#define AT1_SU_SAMPLES   512                ///< number of samples in a sound unit
45
#define AT1_FRAME_SIZE   AT1_SU_SIZE * 2
46
#define AT1_SU_MAX_BITS  AT1_SU_SIZE * 8
47
#define AT1_MAX_CHANNELS 2
48

  
49
#define AT1_QMF_BANDS    3
50
#define IDX_LOW_BAND     0
51
#define IDX_MID_BAND     1
52
#define IDX_HIGH_BAND    2
53

  
54
/**
55
 * Sound unit struct, one unit is used per channel
56
 */
57
typedef struct {
58
    int                 log2_block_count[AT1_QMF_BANDS];    ///< log2 number of blocks in a band
59
    int                 num_bfus;                           ///< number of Block Floating Units
60
    int                 idwls[AT1_MAX_BFU];                 ///< the word length indexes for each BFU
61
    int                 idsfs[AT1_MAX_BFU];                 ///< the scalefactor indexes for each BFU
62
    float*              spectrum[2];
63
    DECLARE_ALIGNED_16(float,spec1[AT1_SU_SAMPLES]);        ///< mdct buffer
64
    DECLARE_ALIGNED_16(float,spec2[AT1_SU_SAMPLES]);        ///< mdct buffer
65
    DECLARE_ALIGNED_16(float,fst_qmf_delay[46]);            ///< delay line for the 1st stacked QMF filter
66
    DECLARE_ALIGNED_16(float,snd_qmf_delay[46]);            ///< delay line for the 2nd stacked QMF filter
67
    DECLARE_ALIGNED_16(float,last_qmf_delay[256+23]);       ///< delay line for the last stacked QMF filter
68
} AT1SUCtx;
69

  
70
/**
71
 * The atrac1 context, holds all needed parameters for decoding
72
 */
73
typedef struct {
74
    AT1SUCtx            SUs[AT1_MAX_CHANNELS];              ///< channel sound unit
75
    DECLARE_ALIGNED_16(float,spec[AT1_SU_SAMPLES]);         ///< the mdct spectrum buffer
76
    DECLARE_ALIGNED_16(float,short_buf[64]);                ///< buffer for the short mode
77
    DECLARE_ALIGNED_16(float, low[256]);
78
    DECLARE_ALIGNED_16(float, mid[256]);
79
    DECLARE_ALIGNED_16(float,high[512]);
80
    float*              bands[3];
81
    float               out_samples[AT1_MAX_CHANNELS][AT1_SU_SAMPLES];
82
    MDCTContext         mdct_ctx[3];
83
    int                 channels;
84
    DSPContext          dsp;
85
} AT1Ctx;
86

  
87
static float *short_window;
88
static float *mid_window;
89
DECLARE_ALIGNED_16(static float, long_window[256]);
90
static float *window_per_band[3];
91

  
92
/** size of the transform in samples in the long mode for each QMF band */
93
static const uint16_t samples_per_band[3] = {128, 128, 256};
94
static const uint8_t   mdct_long_nbits[3] = {7, 7, 8};
95

  
96

  
97
static void at1_imdct(AT1Ctx *q, float *spec, float *out, int nbits, int rev_spec)
98
{
99
    MDCTContext* mdct_context;
100
    int transf_size = 1 << nbits;
101

  
102
    mdct_context = &q->mdct_ctx[nbits - 5 - (nbits>6)];
103

  
104
    if (rev_spec) {
105
        int i;
106
        for (i=0 ; i<transf_size/2 ; i++)
107
            FFSWAP(float, spec[i], spec[transf_size-1-i]);
108
    }
109
    ff_imdct_half(mdct_context,out,spec);
110
}
111

  
112

  
113
static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
114
{
115
    int             band_num, band_samples, log2_block_count, nbits, num_blocks, block_size;
116
    unsigned int    start_pos, ref_pos=0, pos = 0;
117

  
118
    for (band_num=0 ; band_num<AT1_QMF_BANDS ; band_num++) {
119
        band_samples = samples_per_band[band_num];
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        log2_block_count = su->log2_block_count[band_num];
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        /* number of mdct blocks in the current QMF band: 1 - for long mode */
123
        /* 4 for short mode(low/middle bands) and 8 for short mode(high band)*/
124
        num_blocks = 1 << log2_block_count;
125

  
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        /* mdct block size in samples: 128 (long mode, low & mid bands), */
127
        /* 256 (long mode, high band) and 32 (short mode, all bands) */
128
        block_size = band_samples >> log2_block_count;
129

  
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        /* calc transform size in bits according to the block_size_mode */
131
        nbits = mdct_long_nbits[band_num] - log2_block_count;
132

  
133
        if (nbits!=5 && nbits!=7 && nbits!=8)
134
            return -1;
135

  
136
        if (num_blocks == 1) {
137
            at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos], nbits, band_num);
138
            pos += block_size; // move to the next mdct block in the spectrum
139
        } else {
140
            /* calc start position for the 1st short block: 96(128) or 112(256) */
141
            start_pos = (band_samples * (num_blocks - 1)) >> (log2_block_count + 1);
142
            memset(&su->spectrum[0][ref_pos], 0, sizeof(float) * (band_samples * 2));
143

  
144
            for (; num_blocks!=0 ; num_blocks--) {
145
                /* use hardcoded nbits for the short mode */
146
                at1_imdct(q, &q->spec[pos], q->short_buf, 5, band_num);
147

  
148
                /* overlap and window between short blocks */
149
                q->dsp.vector_fmul_window(&su->spectrum[0][ref_pos+start_pos],
150
                    &su->spectrum[0][ref_pos+start_pos],q->short_buf,short_window, 0, 16);
151
                start_pos += 32; // use hardcoded block_size
152
                pos += 32;
153
            }
154
        }
155

  
156
        /* overlap and window with the previous frame and output the result */
157
        q->dsp.vector_fmul_window(q->bands[band_num], &su->spectrum[1][ref_pos+band_samples/2],
158
            &su->spectrum[0][ref_pos], window_per_band[band_num], 0, band_samples/2);
159

  
160
        ref_pos += band_samples;
161
    }
162

  
163
    /* Swap buffers so the mdct overlap works */
164
    FFSWAP(float*, su->spectrum[0], su->spectrum[1]);
165

  
166
    return 0;
167
}
168

  
169

  
170
static int at1_parse_block_size_mode(GetBitContext* gb, int log2_block_count[AT1_QMF_BANDS])
171
{
172
    int log2_block_count_tmp, i;
173

  
174
    for(i=0 ; i<2 ; i++) {
175
        /* low and mid band */
176
        log2_block_count_tmp = get_bits(gb, 2);
177
        if (log2_block_count_tmp & 1)
178
            return -1;
179
        log2_block_count[i] = 2 - log2_block_count_tmp;
180
    }
181

  
182
    /* high band */
183
    log2_block_count_tmp = get_bits(gb, 2);
184
    if (log2_block_count_tmp != 0 && log2_block_count_tmp != 3)
185
        return -1;
186
    log2_block_count[IDX_HIGH_BAND] = 3 - log2_block_count_tmp;
187

  
188
    skip_bits(gb, 2);
189
    return 0;
190
}
191

  
192

  
193
static int at1_unpack_dequant(GetBitContext* gb, AT1SUCtx* su, float spec[AT1_SU_SAMPLES])
194
{
195
    int bits_used, band_num, bfu_num, i;
196

  
197
    /* parse the info byte (2nd byte) telling how much BFUs were coded */
198
    su->num_bfus = bfu_amount_tab1[get_bits(gb, 3)];
199

  
200
    /* calc number of consumed bits:
201
        num_BFUs * (idwl(4bits) + idsf(6bits)) + log2_block_count(8bits) + info_byte(8bits)
202
        + info_byte_copy(8bits) + log2_block_count_copy(8bits) */
203
    bits_used = su->num_bfus * 10 + 32 +
204
                bfu_amount_tab2[get_bits(gb, 2)] +
205
                (bfu_amount_tab3[get_bits(gb, 3)] << 1);
206

  
207
    /* get word length index (idwl) for each BFU */
208
    for (i=0 ; i<su->num_bfus ; i++)
209
        su->idwls[i] = get_bits(gb, 4);
210

  
211
    /* get scalefactor index (idsf) for each BFU */
212
    for (i=0 ; i<su->num_bfus ; i++)
213
        su->idsfs[i] = get_bits(gb, 6);
214

  
215
    /* zero idwl/idsf for empty BFUs */
216
    for (i = su->num_bfus; i < AT1_MAX_BFU; i++)
217
        su->idwls[i] = su->idsfs[i] = 0;
218

  
219
    /* read in the spectral data and reconstruct MDCT spectrum of this channel */
220
    for (band_num=0 ; band_num<AT1_QMF_BANDS ; band_num++) {
221
        for (bfu_num=bfu_bands_t[band_num] ; bfu_num<bfu_bands_t[band_num+1] ; bfu_num++) {
222
            int pos;
223

  
224
            int num_specs = specs_per_bfu[bfu_num];
225
            int word_len  = !!su->idwls[bfu_num] + su->idwls[bfu_num];
226
            float scale_factor = sf_table[su->idsfs[bfu_num]];
227
            bits_used    += word_len * num_specs; /* add number of bits consumed by current BFU */
228

  
229
            /* check for bitstream overflow */
230
            if (bits_used > AT1_SU_MAX_BITS)
231
                return -1;
232

  
233
            /* get the position of the 1st spec according to the block size mode */
234
            pos = su->log2_block_count[band_num] ? bfu_start_short[bfu_num] : bfu_start_long[bfu_num];
235

  
236
            if (word_len) {
237
                float   max_quant = 1.0/(float)((1 << (word_len - 1)) - 1);
238

  
239
                for (i=0 ; i<num_specs ; i++) {
240
                    /* read in a quantized spec and convert it to
241
                     * signed int and then inverse quantization
242
                     */
243
                    spec[pos+i] = get_sbits(gb, word_len) * scale_factor * max_quant;
244
                }
245
            } else { /* word_len = 0 -> empty BFU, zero all specs in the emty BFU */
246
                memset(&spec[pos], 0, num_specs*sizeof(float));
247
            }
248
        }
249
    }
250

  
251
    return 0;
252
}
253

  
254

  
255
void at1_subband_synthesis(AT1Ctx *q, AT1SUCtx* su, float *pOut)
256
{
257
    float   temp[256];
258
    float   iqmf_temp[512 + 46];
259

  
260
    /* combine low and middle bands */
261
    atrac_iqmf(q->bands[0], q->bands[1], 128, temp, su->fst_qmf_delay, iqmf_temp);
262

  
263
    /* delay the signal of the high band by 23 samples */
264
    memcpy( su->last_qmf_delay,     &su->last_qmf_delay[256], sizeof(float)*23);
265
    memcpy(&su->last_qmf_delay[23], q->bands[2],       sizeof(float)*256);
266

  
267
    /* combine (low + middle) and high bands */
268
    atrac_iqmf(temp, su->last_qmf_delay, 256, pOut, su->snd_qmf_delay, iqmf_temp);
269
}
270

  
271

  
272
static int atrac1_decode_frame(AVCodecContext *avctx,
273
            void *data, int *data_size,
274
            AVPacket *avpkt)
275
{
276
    const uint8_t *buf = avpkt->data;
277
    int buf_size = avpkt->size;
278
    AT1Ctx *q = avctx->priv_data;
279
    int ch, ret, i;
280
    GetBitContext gb;
281
    float* samples = data;
282

  
283

  
284
    if (buf_size < 212 * q->channels) {
285
        av_log(q,AV_LOG_ERROR,"Not enought data to decode!\n");
286
        return -1;
287
    }
288

  
289
    for (ch=0 ; ch<q->channels ; ch++) {
290
        AT1SUCtx* su = &q->SUs[ch];
291

  
292
        init_get_bits(&gb, &buf[212*ch], 212*8);
293

  
294
        /* parse block_size_mode, 1st byte */
295
        ret = at1_parse_block_size_mode(&gb, su->log2_block_count);
296
        if (ret < 0)
297
            return ret;
298

  
299
        ret = at1_unpack_dequant(&gb, su, q->spec);
300
        if (ret < 0)
301
            return ret;
302

  
303
        ret = at1_imdct_block(su, q);
304
        if (ret < 0)
305
            return ret;
306
        at1_subband_synthesis(q, su, q->out_samples[ch]);
307
    }
308

  
309
    /* round, convert to 16bit and interleave */
310
    if (q->channels == 1) {
311
        /* mono */
312
        q->dsp.vector_clipf(samples, q->out_samples[0], -32700./(1<<15), 32700./(1<<15), AT1_SU_SAMPLES);
313
    } else {
314
        /* stereo */
315
        for (i = 0; i < AT1_SU_SAMPLES; i++) {
316
            samples[i*2]   = av_clipf(q->out_samples[0][i], -32700./(1<<15), 32700./(1<<15));
317
            samples[i*2+1] = av_clipf(q->out_samples[1][i], -32700./(1<<15), 32700./(1<<15));
318
        }
319
    }
320

  
321
    *data_size = q->channels * AT1_SU_SAMPLES * sizeof(*samples);
322
    return avctx->block_align;
323
}
324

  
325

  
326
static av_cold void init_mdct_windows(void)
327
{
328
    int i;
329

  
330
    /** The mid and long windows uses the same sine window splitted
331
     *  in the middle and wrapped into zero/one regions as follows:
332
     *
333
     *                   region of "ones"
334
     *               -------------
335
     *              /
336
     *             / 1st half
337
     *            / of the sine
338
     *           /  window
339
     * ---------/
340
     * zero region
341
     *
342
     * The mid and short windows are subsets of the long window.
343
     */
344

  
345
    /* Build "zero" region */
346
    memset(long_window, 0, sizeof(long_window));
347
    /* Build sine window region */
348
    short_window = &long_window[112];
349
    ff_sine_window_init(short_window,32);
350
    /* Build "ones" region */
351
    for (i = 0; i < 112; i++)
352
        long_window[144 + i] = 1.0f;
353
    /* Save the mid window subset start */
354
    mid_window = &long_window[64];
355

  
356
    /* Prepare the window table */
357
    window_per_band[0] = mid_window;
358
    window_per_band[1] = mid_window;
359
    window_per_band[2] = long_window;
360
}
361

  
362
static av_cold int atrac1_decode_init(AVCodecContext *avctx)
363
{
364
    AT1Ctx *q = avctx->priv_data;
365

  
366
    avctx->sample_fmt = SAMPLE_FMT_FLT;
367

  
368
    q->channels = avctx->channels;
369

  
370
    /* Init the mdct transforms */
371
    ff_mdct_init(&q->mdct_ctx[0], 6, 1, -1.0/ (1<<15));
372
    ff_mdct_init(&q->mdct_ctx[1], 8, 1, -1.0/ (1<<15));
373
    ff_mdct_init(&q->mdct_ctx[2], 9, 1, -1.0/ (1<<15));
374
    init_mdct_windows();
375

  
376
    atrac_generate_tables();
377

  
378
    dsputil_init(&q->dsp, avctx);
379

  
380
    q->bands[0] = q->low;
381
    q->bands[1] = q->mid;
382
    q->bands[2] = q->high;
383

  
384
    /* Prepare the mdct overlap buffers */
385
    q->SUs[0].spectrum[0] = q->SUs[0].spec1;
386
    q->SUs[0].spectrum[1] = q->SUs[0].spec2;
387
    q->SUs[1].spectrum[0] = q->SUs[1].spec1;
388
    q->SUs[1].spectrum[1] = q->SUs[1].spec2;
389

  
390
    return 0;
391
}
392

  
393
AVCodec atrac1_decoder = {
394
    .name = "atrac1",
395
    .type = CODEC_TYPE_AUDIO,
396
    .id = CODEC_ID_ATRAC1,
397
    .priv_data_size = sizeof(AT1Ctx),
398
    .init = atrac1_decode_init,
399
    .close = NULL,
400
    .decode = atrac1_decode_frame,
401
    .long_name = NULL_IF_CONFIG_SMALL("Atrac 1 (Adaptive TRansform Acoustic Coding)"),
402
};
libavcodec/atrac1data.h
1
/*
2
 * Atrac 1 compatible decoder data
3
 * Copyright (c) 2009 Maxim Poliakovski
4
 * Copyright (c) 2009 Benjamin Larsson
5
 *
6
 * This file is part of FFmpeg.
7
 *
8
 * FFmpeg is free software; you can redistribute it and/or
9
 * modify it under the terms of the GNU Lesser General Public
10
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * FFmpeg is distributed in the hope that it will be useful,
14
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16
 * Lesser General Public License for more details.
17
 *
18
 * You should have received a copy of the GNU Lesser General Public
19
 * License along with FFmpeg; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22

  
23
/**
24
 * @file libavcodec/atrac1data.h
25
 * Atrac 1 compatible decoder data
26
 */
27

  
28
#ifndef AVCODEC_ATRAC1DATA_H
29
#define AVCODEC_ATRAC1DATA_H
30

  
31
static const uint8_t bfu_amount_tab1[8] = {20,  28,  32,  36, 40, 44, 48, 52};
32
static const uint8_t bfu_amount_tab2[4] = { 0, 112, 176, 208};
33
static const uint8_t bfu_amount_tab3[8] = { 0,  24,  36,  48, 72, 108, 132, 156};
34

  
35
/** number of BFUs in each QMF band */
36
static const uint8_t bfu_bands_t[4]  = {0, 20, 36, 52};
37

  
38
/** number of spectral lines in each BFU
39
 *  block floating unit = group of spectral frequencies having the
40
 *  same quantization parameters like word length and scale factor
41
 */
42
static const uint8_t specs_per_bfu[52] = {
43
     8,  8,  8,  8,  4,  4,  4,  4,  8,  8,  8,  8,  6,  6,  6,  6, 6, 6, 6, 6, // low band
44
     6,  6,  6,  6,  7,  7,  7,  7,  9,  9,  9,  9, 10, 10, 10, 10,             // midle band
45
    12, 12, 12, 12, 12, 12, 12, 12, 20, 20, 20, 20, 20, 20, 20, 20              // high band
46
};
47

  
48
/** start position of each BFU in the MDCT spectrum for the long mode */
49
static const uint16_t bfu_start_long[52] = {
50
      0,   8,  16,  24,  32,  36,  40,  44,  48,  56,  64,  72,  80,  86,  92,  98, 104, 110, 116, 122,
51
    128, 134, 140, 146, 152, 159, 166, 173, 180, 189, 198, 207, 216, 226, 236, 246,
52
    256, 268, 280, 292, 304, 316, 328, 340, 352, 372, 392, 412, 432, 452, 472, 492,
53
};
54

  
55
/** start position of each BFU in the MDCT spectrum for the short mode */
56
static const uint16_t bfu_start_short[52] = {
57
      0,  32,  64,  96,   8,  40,  72, 104,  12,  44,  76, 108,  20,  52,  84, 116, 26, 58, 90, 122,
58
    128, 160, 192, 224, 134, 166, 198, 230, 141, 173, 205, 237, 150, 182, 214, 246,
59
    256, 288, 320, 352, 384, 416, 448, 480, 268, 300, 332, 364, 396, 428, 460, 492
60
};
61

  
62
#endif /* AVCODEC_ATRAC1DATA_H */

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