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1
/*
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 * IMC compatible decoder
3
 * Copyright (c) 2002-2004 Maxim Poliakovski
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 * Copyright (c) 2006 Benjamin Larsson
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 * Copyright (c) 2006 Konstantin Shishkov
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
10
 * modify it under the terms of the GNU Lesser General Public
11
 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
15
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
23

    
24
/**
25
 *  @file imc.c IMC - Intel Music Coder
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 *  A mdct based codec using a 256 points large transform
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 *  divied into 32 bands with some mix of scale factors.
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 *  Only mono is supported.
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 *
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 */
31

    
32

    
33
#include <math.h>
34
#include <stddef.h>
35
#include <stdio.h>
36

    
37
#define ALT_BITSTREAM_READER
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#include "avcodec.h"
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#include "bitstream.h"
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#include "dsputil.h"
41

    
42
#include "imcdata.h"
43

    
44
#define IMC_BLOCK_SIZE 64
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#define IMC_FRAME_ID 0x21
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#define BANDS 32
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#define COEFFS 256
48

    
49
typedef struct {
50
    float old_floor[BANDS];
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    float flcoeffs1[BANDS];
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    float flcoeffs2[BANDS];
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    float flcoeffs3[BANDS];
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    float flcoeffs4[BANDS];
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    float flcoeffs5[BANDS];
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    float flcoeffs6[BANDS];
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    float CWdecoded[COEFFS];
58

    
59
    /** MDCT tables */
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    //@{
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    float mdct_sine_window[COEFFS];
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    float post_cos[COEFFS];
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    float post_sin[COEFFS];
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    float pre_coef1[COEFFS];
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    float pre_coef2[COEFFS];
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    float last_fft_im[COEFFS];
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    //@}
68

    
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    int bandWidthT[BANDS];     ///< codewords per band
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    int bitsBandT[BANDS];      ///< how many bits per codeword in band
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    int CWlengthT[COEFFS];     ///< how many bits in each codeword
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    int levlCoeffBuf[BANDS];
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    int bandFlagsBuf[BANDS];   ///< flags for each band
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    int sumLenArr[BANDS];      ///< bits for all coeffs in band
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    int skipFlagRaw[BANDS];    ///< skip flags are stored in raw form or not
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    int skipFlagBits[BANDS];   ///< bits used to code skip flags
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    int skipFlagCount[BANDS];  ///< skipped coeffients per band
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    int skipFlags[COEFFS];     ///< skip coefficient decoding or not
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    int codewords[COEFFS];     ///< raw codewords read from bitstream
80
    float sqrt_tab[30];
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    GetBitContext gb;
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    VLC huffman_vlc[4][4];
83
    int decoder_reset;
84
    float one_div_log2;
85

    
86
    DSPContext dsp;
87
    FFTContext fft;
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    DECLARE_ALIGNED_16(FFTComplex, samples[COEFFS/2]);
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    DECLARE_ALIGNED_16(float, out_samples[COEFFS]);
90
} IMCContext;
91

    
92

    
93
static int imc_decode_init(AVCodecContext * avctx)
94
{
95
    int i, j;
96
    IMCContext *q = avctx->priv_data;
97
    double r1, r2;
98

    
99
    q->decoder_reset = 1;
100

    
101
    for(i = 0; i < BANDS; i++)
102
        q->old_floor[i] = 1.0;
103

    
104
    /* Build mdct window, a simple sine window normalized with sqrt(2) */
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    for(i = 0; i < COEFFS; i++)
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        q->mdct_sine_window[i] = sin((i + 0.5) / 512.0 * M_PI) * sqrt(2.0);
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    for(i = 0; i < COEFFS/2; i++){
108
        q->post_cos[i] = cos(i / 256.0 * M_PI);
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        q->post_sin[i] = sin(i / 256.0 * M_PI);
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111
        r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
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        r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
113

    
114
        if (i & 0x1)
115
        {
116
            q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
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            q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
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        }
119
        else
120
        {
121
            q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
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            q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
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        }
124

    
125
        q->last_fft_im[i] = 0;
126
    }
127

    
128
    /* Generate a square root table */
129

    
130
    for(i = 0; i < 30; i++) {
131
        q->sqrt_tab[i] = sqrt(i);
132
    }
133

    
134
    /* initialize the VLC tables */
135
    for(i = 0; i < 4 ; i++) {
136
        for(j = 0; j < 4; j++) {
137
            init_vlc (&q->huffman_vlc[i][j], 9, imc_huffman_sizes[i],
138
                     imc_huffman_lens[i][j], 1, 1,
139
                     imc_huffman_bits[i][j], 2, 2, 1);
140
        }
141
    }
142
    q->one_div_log2 = 1/log(2);
143

    
144
    ff_fft_init(&q->fft, 7, 1);
145
    dsputil_init(&q->dsp, avctx);
146
    return 0;
147
}
148

    
149
static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
150
                                float* flcoeffs3, float* flcoeffs5)
151
{
152
    float   workT1[BANDS];
153
    float   workT2[BANDS];
154
    float   workT3[BANDS];
155
    float   snr_limit = 1.e-30;
156
    float   accum = 0.0;
157
    int i, cnt2;
158

    
159
    for(i = 0; i < BANDS; i++) {
160
        flcoeffs5[i] = workT2[i] = 0.0;
161
        if (bandWidthT[i]){
162
            workT1[i] = flcoeffs1[i] * flcoeffs1[i];
163
            flcoeffs3[i] = 2.0 * flcoeffs2[i];
164
        } else {
165
            workT1[i] = 0.0;
166
            flcoeffs3[i] = -30000.0;
167
        }
168
        workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
169
        if (workT3[i] <= snr_limit)
170
            workT3[i] = 0.0;
171
    }
172

    
173
    for(i = 0; i < BANDS; i++) {
174
        for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++)
175
            flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
176
        workT2[cnt2-1] = workT2[cnt2-1] + workT3[i];
177
    }
178

    
179
    for(i = 1; i < BANDS; i++) {
180
        accum = (workT2[i-1] + accum) * imc_weights1[i-1];
181
        flcoeffs5[i] += accum;
182
    }
183

    
184
    for(i = 0; i < BANDS; i++)
185
        workT2[i] = 0.0;
186

    
187
    for(i = 0; i < BANDS; i++) {
188
        for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
189
            flcoeffs5[cnt2] += workT3[i];
190
        workT2[cnt2+1] += workT3[i];
191
    }
192

    
193
    accum = 0.0;
194

    
195
    for(i = BANDS-2; i >= 0; i--) {
196
        accum = (workT2[i+1] + accum) * imc_weights2[i];
197
        flcoeffs5[i] += accum;
198
        //there is missing code here, but it seems to never be triggered
199
    }
200
}
201

    
202

    
203
static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
204
{
205
    int i;
206
    VLC *hufftab[4];
207
    int start = 0;
208
    const uint8_t *cb_sel;
209
    int s;
210

    
211
    s = stream_format_code >> 1;
212
    hufftab[0] = &q->huffman_vlc[s][0];
213
    hufftab[1] = &q->huffman_vlc[s][1];
214
    hufftab[2] = &q->huffman_vlc[s][2];
215
    hufftab[3] = &q->huffman_vlc[s][3];
216
    cb_sel = imc_cb_select[s];
217

    
218
    if(stream_format_code & 4)
219
        start = 1;
220
    if(start)
221
        levlCoeffs[0] = get_bits(&q->gb, 7);
222
    for(i = start; i < BANDS; i++){
223
        levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
224
        if(levlCoeffs[i] == 17)
225
            levlCoeffs[i] += get_bits(&q->gb, 4);
226
    }
227
}
228

    
229
static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
230
                                         float* flcoeffs2)
231
{
232
    int i, level;
233
    float tmp, tmp2;
234
    //maybe some frequency division thingy
235

    
236
    flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
237
    flcoeffs2[0] = log(flcoeffs1[0])/log(2);
238
    tmp = flcoeffs1[0];
239
    tmp2 = flcoeffs2[0];
240

    
241
    for(i = 1; i < BANDS; i++) {
242
        level = levlCoeffBuf[i];
243
        if (level == 16) {
244
            flcoeffs1[i] = 1.0;
245
            flcoeffs2[i] = 0.0;
246
        } else {
247
            if (level < 17)
248
                level -=7;
249
            else if (level <= 24)
250
                level -=32;
251
            else
252
                level -=16;
253

    
254
            tmp  *= imc_exp_tab[15 + level];
255
            tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
256
            flcoeffs1[i] = tmp;
257
            flcoeffs2[i] = tmp2;
258
        }
259
    }
260
}
261

    
262

    
263
static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
264
                                          float* flcoeffs2) {
265
    int i;
266
        //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
267
        //      and flcoeffs2 old scale factors
268
        //      might be incomplete due to a missing table that is in the binary code
269
    for(i = 0; i < BANDS; i++) {
270
        flcoeffs1[i] = 0;
271
        if(levlCoeffBuf[i] < 16) {
272
            flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
273
            flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
274
        } else {
275
            flcoeffs1[i] = old_floor[i];
276
        }
277
    }
278
}
279

    
280
/**
281
 * Perform bit allocation depending on bits available
282
 */
283
static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
284
    int i, j;
285
    const float limit = -1.e20;
286
    float highest = 0.0;
287
    int indx;
288
    int t1 = 0;
289
    int t2 = 1;
290
    float summa = 0.0;
291
    int iacc = 0;
292
    int summer = 0;
293
    int rres, cwlen;
294
    float lowest = 1.e10;
295
    int low_indx = 0;
296
    float workT[32];
297
    int flg;
298
    int found_indx = 0;
299

    
300
    for(i = 0; i < BANDS; i++)
301
        highest = FFMAX(highest, q->flcoeffs1[i]);
302

    
303
    for(i = 0; i < BANDS-1; i++) {
304
        q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
305
    }
306
    q->flcoeffs4[BANDS - 1] = limit;
307

    
308
    highest = highest * 0.25;
309

    
310
    for(i = 0; i < BANDS; i++) {
311
        indx = -1;
312
        if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
313
            indx = 0;
314

    
315
        if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
316
            indx = 1;
317

    
318
        if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
319
            indx = 2;
320

    
321
        if (indx == -1)
322
            return -1;
323

    
324
        q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
325
    }
326

    
327
    if (stream_format_code & 0x2) {
328
        q->flcoeffs4[0] = limit;
329
        q->flcoeffs4[1] = limit;
330
        q->flcoeffs4[2] = limit;
331
        q->flcoeffs4[3] = limit;
332
    }
333

    
334
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
335
        iacc += q->bandWidthT[i];
336
        summa += q->bandWidthT[i] * q->flcoeffs4[i];
337
    }
338
    q->bandWidthT[BANDS-1] = 0;
339
    summa = (summa * 0.5 - freebits) / iacc;
340

    
341

    
342
    for(i = 0; i < BANDS/2; i++) {
343
        rres = summer - freebits;
344
        if((rres >= -8) && (rres <= 8)) break;
345

    
346
        summer = 0;
347
        iacc = 0;
348

    
349
        for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
350
            cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
351

    
352
            q->bitsBandT[j] = cwlen;
353
            summer += q->bandWidthT[j] * cwlen;
354

    
355
            if (cwlen > 0)
356
                iacc += q->bandWidthT[j];
357
        }
358

    
359
        flg = t2;
360
        t2 = 1;
361
        if (freebits < summer)
362
            t2 = -1;
363
        if (i == 0)
364
            flg = t2;
365
        if(flg != t2)
366
            t1++;
367

    
368
        summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
369
    }
370

    
371
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
372
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
373
            q->CWlengthT[j] = q->bitsBandT[i];
374
    }
375

    
376
    if (freebits > summer) {
377
        for(i = 0; i < BANDS; i++) {
378
            workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
379
        }
380

    
381
        highest = 0.0;
382

    
383
        do{
384
            if (highest <= -1.e20)
385
                break;
386

    
387
            found_indx = 0;
388
            highest = -1.e20;
389

    
390
            for(i = 0; i < BANDS; i++) {
391
                if (workT[i] > highest) {
392
                    highest = workT[i];
393
                    found_indx = i;
394
                }
395
            }
396

    
397
            if (highest > -1.e20) {
398
                workT[found_indx] -= 2.0;
399
                if (++(q->bitsBandT[found_indx]) == 6)
400
                    workT[found_indx] = -1.e20;
401

    
402
                for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
403
                    q->CWlengthT[j]++;
404
                    summer++;
405
                }
406
            }
407
        }while (freebits > summer);
408
    }
409
    if (freebits < summer) {
410
        for(i = 0; i < BANDS; i++) {
411
            workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
412
        }
413
        if (stream_format_code & 0x2) {
414
            workT[0] = 1.e20;
415
            workT[1] = 1.e20;
416
            workT[2] = 1.e20;
417
            workT[3] = 1.e20;
418
        }
419
        while (freebits < summer){
420
            lowest = 1.e10;
421
            low_indx = 0;
422
            for(i = 0; i < BANDS; i++) {
423
                if (workT[i] < lowest) {
424
                    lowest = workT[i];
425
                    low_indx = i;
426
                }
427
            }
428
            //if(lowest >= 1.e10) break;
429
            workT[low_indx] = lowest + 2.0;
430

    
431
            if (!(--q->bitsBandT[low_indx]))
432
                workT[low_indx] = 1.e20;
433

    
434
            for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
435
                if(q->CWlengthT[j] > 0){
436
                    q->CWlengthT[j]--;
437
                    summer--;
438
                }
439
            }
440
        }
441
    }
442
    return 0;
443
}
444

    
445
static void imc_get_skip_coeff(IMCContext* q) {
446
    int i, j;
447

    
448
    memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
449
    memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
450
    for(i = 0; i < BANDS; i++) {
451
        if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
452
            continue;
453

    
454
        if (!q->skipFlagRaw[i]) {
455
            q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
456

    
457
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
458
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
459
                    q->skipFlagCount[i]++;
460
            }
461
        } else {
462
            for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
463
                if(!get_bits1(&q->gb)){//0
464
                    q->skipFlagBits[i]++;
465
                    q->skipFlags[j]=1;
466
                    q->skipFlags[j+1]=1;
467
                    q->skipFlagCount[i] += 2;
468
                }else{
469
                    if(get_bits1(&q->gb)){//11
470
                        q->skipFlagBits[i] +=2;
471
                        q->skipFlags[j]=0;
472
                        q->skipFlags[j+1]=1;
473
                        q->skipFlagCount[i]++;
474
                    }else{
475
                        q->skipFlagBits[i] +=3;
476
                        q->skipFlags[j+1]=0;
477
                        if(!get_bits1(&q->gb)){//100
478
                            q->skipFlags[j]=1;
479
                            q->skipFlagCount[i]++;
480
                        }else{//101
481
                            q->skipFlags[j]=0;
482
                        }
483
                    }
484
                }
485
            }
486

    
487
            if (j < band_tab[i+1]) {
488
                q->skipFlagBits[i]++;
489
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
490
                    q->skipFlagCount[i]++;
491
            }
492
        }
493
    }
494
}
495

    
496
/**
497
 * Increase highest' band coefficient sizes as some bits won't be used
498
 */
499
static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
500
    float workT[32];
501
    int corrected = 0;
502
    int i, j;
503
    float highest = 0;
504
    int found_indx=0;
505

    
506
    for(i = 0; i < BANDS; i++) {
507
        workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
508
    }
509

    
510
    while (corrected < summer) {
511
        if(highest <= -1.e20)
512
            break;
513

    
514
        highest = -1.e20;
515

    
516
        for(i = 0; i < BANDS; i++) {
517
            if (workT[i] > highest) {
518
                highest = workT[i];
519
                found_indx = i;
520
            }
521
        }
522

    
523
        if (highest > -1.e20) {
524
            workT[found_indx] -= 2.0;
525
            if (++(q->bitsBandT[found_indx]) == 6)
526
                workT[found_indx] = -1.e20;
527

    
528
            for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
529
                if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
530
                    q->CWlengthT[j]++;
531
                    corrected++;
532
                }
533
            }
534
        }
535
    }
536
}
537

    
538
static void imc_imdct256(IMCContext *q) {
539
    int i;
540
    float re, im;
541

    
542
    /* prerotation */
543
    for(i=0; i < COEFFS/2; i++){
544
        q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
545
                           (q->pre_coef2[i] * q->CWdecoded[i*2]);
546
        q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
547
                           (q->pre_coef1[i] * q->CWdecoded[i*2]);
548
    }
549

    
550
    /* FFT */
551
    ff_fft_permute(&q->fft, q->samples);
552
    ff_fft_calc (&q->fft, q->samples);
553

    
554
    /* postrotation, window and reorder */
555
    for(i = 0; i < COEFFS/2; i++){
556
        re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
557
        im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
558
        q->out_samples[i*2] = (q->mdct_sine_window[COEFFS-1-i*2] * q->last_fft_im[i]) + (q->mdct_sine_window[i*2] * re);
559
        q->out_samples[COEFFS-1-i*2] = (q->mdct_sine_window[i*2] * q->last_fft_im[i]) - (q->mdct_sine_window[COEFFS-1-i*2] * re);
560
        q->last_fft_im[i] = im;
561
    }
562
}
563

    
564
static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
565
    int i, j;
566
    int middle_value, cw_len, max_size;
567
    const float* quantizer;
568

    
569
    for(i = 0; i < BANDS; i++) {
570
        for(j = band_tab[i]; j < band_tab[i+1]; j++) {
571
            q->CWdecoded[j] = 0;
572
            cw_len = q->CWlengthT[j];
573

    
574
            if (cw_len <= 0 || q->skipFlags[j])
575
                continue;
576

    
577
            max_size = 1 << cw_len;
578
            middle_value = max_size >> 1;
579

    
580
            if (q->codewords[j] >= max_size || q->codewords[j] < 0)
581
                return -1;
582

    
583
            if (cw_len >= 4){
584
                quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
585
                if (q->codewords[j] >= middle_value)
586
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
587
                else
588
                    q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
589
            }else{
590
                quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
591
                if (q->codewords[j] >= middle_value)
592
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
593
                else
594
                    q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
595
            }
596
        }
597
    }
598
    return 0;
599
}
600

    
601

    
602
static int imc_get_coeffs (IMCContext* q) {
603
    int i, j, cw_len, cw;
604

    
605
    for(i = 0; i < BANDS; i++) {
606
        if(!q->sumLenArr[i]) continue;
607
        if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
608
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
609
                cw_len = q->CWlengthT[j];
610
                cw = 0;
611

    
612
                if (get_bits_count(&q->gb) + cw_len > 512){
613
//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
614
                    return -1;
615
                }
616

    
617
                if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
618
                    cw = get_bits(&q->gb, cw_len);
619

    
620
                q->codewords[j] = cw;
621
            }
622
        }
623
    }
624
    return 0;
625
}
626

    
627
static int imc_decode_frame(AVCodecContext * avctx,
628
                            void *data, int *data_size,
629
                            const uint8_t * buf, int buf_size)
630
{
631

    
632
    IMCContext *q = avctx->priv_data;
633

    
634
    int stream_format_code;
635
    int imc_hdr, i, j;
636
    int flag;
637
    int bits, summer;
638
    int counter, bitscount;
639
    uint16_t buf16[IMC_BLOCK_SIZE / 2];
640

    
641
    for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
642
        buf16[i] = bswap_16(((const uint16_t*)buf)[i]);
643

    
644
    init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
645

    
646
    /* Check the frame header */
647
    imc_hdr = get_bits(&q->gb, 9);
648
    if (imc_hdr != IMC_FRAME_ID) {
649
        av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
650
        av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
651
        return -1;
652
    }
653
    stream_format_code = get_bits(&q->gb, 3);
654

    
655
    if(stream_format_code & 1){
656
        av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
657
        return -1;
658
    }
659

    
660
//    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
661

    
662
    if (stream_format_code & 0x04)
663
        q->decoder_reset = 1;
664

    
665
    if(q->decoder_reset) {
666
        memset(q->out_samples, 0, sizeof(q->out_samples));
667
        for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
668
        for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
669
        q->decoder_reset = 0;
670
    }
671

    
672
    flag = get_bits1(&q->gb);
673
    imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
674

    
675
    if (stream_format_code & 0x4)
676
        imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
677
    else
678
        imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);
679

    
680
    memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
681

    
682
    counter = 0;
683
    for (i=0 ; i<BANDS ; i++) {
684
        if (q->levlCoeffBuf[i] == 16) {
685
            q->bandWidthT[i] = 0;
686
            counter++;
687
        } else
688
            q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
689
    }
690
    memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
691
    for(i = 0; i < BANDS-1; i++) {
692
        if (q->bandWidthT[i])
693
            q->bandFlagsBuf[i] = get_bits1(&q->gb);
694
    }
695

    
696
    imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);
697

    
698
    bitscount = 0;
699
    /* first 4 bands will be assigned 5 bits per coefficient */
700
    if (stream_format_code & 0x2) {
701
        bitscount += 15;
702

    
703
        q->bitsBandT[0] = 5;
704
        q->CWlengthT[0] = 5;
705
        q->CWlengthT[1] = 5;
706
        q->CWlengthT[2] = 5;
707
        for(i = 1; i < 4; i++){
708
            bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
709
            q->bitsBandT[i] = bits;
710
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
711
                q->CWlengthT[j] = bits;
712
                bitscount += bits;
713
            }
714
        }
715
    }
716

    
717
    if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
718
        av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
719
        q->decoder_reset = 1;
720
        return -1;
721
    }
722

    
723
    for(i = 0; i < BANDS; i++) {
724
        q->sumLenArr[i] = 0;
725
        q->skipFlagRaw[i] = 0;
726
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
727
            q->sumLenArr[i] += q->CWlengthT[j];
728
        if (q->bandFlagsBuf[i])
729
            if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
730
                q->skipFlagRaw[i] = 1;
731
    }
732

    
733
    imc_get_skip_coeff(q);
734

    
735
    for(i = 0; i < BANDS; i++) {
736
        q->flcoeffs6[i] = q->flcoeffs1[i];
737
        /* band has flag set and at least one coded coefficient */
738
        if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
739
                q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
740
                                   q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
741
        }
742
    }
743

    
744
    /* calculate bits left, bits needed and adjust bit allocation */
745
    bits = summer = 0;
746

    
747
    for(i = 0; i < BANDS; i++) {
748
        if (q->bandFlagsBuf[i]) {
749
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
750
                if(q->skipFlags[j]) {
751
                    summer += q->CWlengthT[j];
752
                    q->CWlengthT[j] = 0;
753
                }
754
            }
755
            bits += q->skipFlagBits[i];
756
            summer -= q->skipFlagBits[i];
757
        }
758
    }
759
    imc_adjust_bit_allocation(q, summer);
760

    
761
    for(i = 0; i < BANDS; i++) {
762
        q->sumLenArr[i] = 0;
763

    
764
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
765
            if (!q->skipFlags[j])
766
                q->sumLenArr[i] += q->CWlengthT[j];
767
    }
768

    
769
    memset(q->codewords, 0, sizeof(q->codewords));
770

    
771
    if(imc_get_coeffs(q) < 0) {
772
        av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
773
        q->decoder_reset = 1;
774
        return 0;
775
    }
776

    
777
    if(inverse_quant_coeff(q, stream_format_code) < 0) {
778
        av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
779
        q->decoder_reset = 1;
780
        return 0;
781
    }
782

    
783
    memset(q->skipFlags, 0, sizeof(q->skipFlags));
784

    
785
    imc_imdct256(q);
786

    
787
    q->dsp.float_to_int16(data, q->out_samples, COEFFS);
788

    
789
    *data_size = COEFFS * sizeof(int16_t);
790

    
791
    return IMC_BLOCK_SIZE;
792
}
793

    
794

    
795
static int imc_decode_close(AVCodecContext * avctx)
796
{
797
    IMCContext *q = avctx->priv_data;
798

    
799
    ff_fft_end(&q->fft);
800
    return 0;
801
}
802

    
803

    
804
AVCodec imc_decoder = {
805
    .name = "imc",
806
    .type = CODEC_TYPE_AUDIO,
807
    .id = CODEC_ID_IMC,
808
    .priv_data_size = sizeof(IMCContext),
809
    .init = imc_decode_init,
810
    .close = imc_decode_close,
811
    .decode = imc_decode_frame,
812
};