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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 Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
10
 * modify it under the terms of the GNU Lesser General Public
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 * 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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 * Libav is distributed in the hope that it will be useful,
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 * 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 Libav; 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
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 *  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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 */
32

    
33

    
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#include <math.h>
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#include <stddef.h>
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#include <stdio.h>
37

    
38
#define ALT_BITSTREAM_READER
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#include "avcodec.h"
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#include "get_bits.h"
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#include "dsputil.h"
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#include "fft.h"
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#include "libavutil/audioconvert.h"
44

    
45
#include "imcdata.h"
46

    
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#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
51

    
52
typedef struct {
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    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];
61

    
62
    /** MDCT tables */
63
    //@{
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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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    //@}
71

    
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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
82
    int codewords[COEFFS];     ///< raw codewords read from bitstream
83
    float sqrt_tab[30];
84
    GetBitContext gb;
85
    int decoder_reset;
86
    float one_div_log2;
87

    
88
    DSPContext dsp;
89
    FFTContext fft;
90
    DECLARE_ALIGNED(16, FFTComplex, samples)[COEFFS/2];
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    float *out_samples;
92
} IMCContext;
93

    
94
static VLC huffman_vlc[4][4];
95

    
96
#define VLC_TABLES_SIZE 9512
97

    
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static const int vlc_offsets[17] = {
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    0,     640, 1156, 1732, 2308, 2852, 3396, 3924,
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    4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE};
101

    
102
static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];
103

    
104
static av_cold int imc_decode_init(AVCodecContext * avctx)
105
{
106
    int i, j;
107
    IMCContext *q = avctx->priv_data;
108
    double r1, r2;
109

    
110
    q->decoder_reset = 1;
111

    
112
    for(i = 0; i < BANDS; i++)
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        q->old_floor[i] = 1.0;
114

    
115
    /* Build mdct window, a simple sine window normalized with sqrt(2) */
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    ff_sine_window_init(q->mdct_sine_window, COEFFS);
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    for(i = 0; i < COEFFS; i++)
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        q->mdct_sine_window[i] *= sqrt(2.0);
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    for(i = 0; i < COEFFS/2; i++){
120
        q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
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        q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);
122

    
123
        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);
125

    
126
        if (i & 0x1)
127
        {
128
            q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
129
            q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
130
        }
131
        else
132
        {
133
            q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
134
            q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
135
        }
136

    
137
        q->last_fft_im[i] = 0;
138
    }
139

    
140
    /* Generate a square root table */
141

    
142
    for(i = 0; i < 30; i++) {
143
        q->sqrt_tab[i] = sqrt(i);
144
    }
145

    
146
    /* initialize the VLC tables */
147
    for(i = 0; i < 4 ; i++) {
148
        for(j = 0; j < 4; j++) {
149
            huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
150
            huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
151
            init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
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                     imc_huffman_lens[i][j], 1, 1,
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                     imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
154
        }
155
    }
156
    q->one_div_log2 = 1/log(2);
157

    
158
    ff_fft_init(&q->fft, 7, 1);
159
    dsputil_init(&q->dsp, avctx);
160
    avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
161
    avctx->channel_layout = (avctx->channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
162
    return 0;
163
}
164

    
165
static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
166
                                float* flcoeffs3, float* flcoeffs5)
167
{
168
    float   workT1[BANDS];
169
    float   workT2[BANDS];
170
    float   workT3[BANDS];
171
    float   snr_limit = 1.e-30;
172
    float   accum = 0.0;
173
    int i, cnt2;
174

    
175
    for(i = 0; i < BANDS; i++) {
176
        flcoeffs5[i] = workT2[i] = 0.0;
177
        if (bandWidthT[i]){
178
            workT1[i] = flcoeffs1[i] * flcoeffs1[i];
179
            flcoeffs3[i] = 2.0 * flcoeffs2[i];
180
        } else {
181
            workT1[i] = 0.0;
182
            flcoeffs3[i] = -30000.0;
183
        }
184
        workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
185
        if (workT3[i] <= snr_limit)
186
            workT3[i] = 0.0;
187
    }
188

    
189
    for(i = 0; i < BANDS; i++) {
190
        for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++)
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            flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
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        workT2[cnt2-1] = workT2[cnt2-1] + workT3[i];
193
    }
194

    
195
    for(i = 1; i < BANDS; i++) {
196
        accum = (workT2[i-1] + accum) * imc_weights1[i-1];
197
        flcoeffs5[i] += accum;
198
    }
199

    
200
    for(i = 0; i < BANDS; i++)
201
        workT2[i] = 0.0;
202

    
203
    for(i = 0; i < BANDS; i++) {
204
        for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
205
            flcoeffs5[cnt2] += workT3[i];
206
        workT2[cnt2+1] += workT3[i];
207
    }
208

    
209
    accum = 0.0;
210

    
211
    for(i = BANDS-2; i >= 0; i--) {
212
        accum = (workT2[i+1] + accum) * imc_weights2[i];
213
        flcoeffs5[i] += accum;
214
        //there is missing code here, but it seems to never be triggered
215
    }
216
}
217

    
218

    
219
static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
220
{
221
    int i;
222
    VLC *hufftab[4];
223
    int start = 0;
224
    const uint8_t *cb_sel;
225
    int s;
226

    
227
    s = stream_format_code >> 1;
228
    hufftab[0] = &huffman_vlc[s][0];
229
    hufftab[1] = &huffman_vlc[s][1];
230
    hufftab[2] = &huffman_vlc[s][2];
231
    hufftab[3] = &huffman_vlc[s][3];
232
    cb_sel = imc_cb_select[s];
233

    
234
    if(stream_format_code & 4)
235
        start = 1;
236
    if(start)
237
        levlCoeffs[0] = get_bits(&q->gb, 7);
238
    for(i = start; i < BANDS; i++){
239
        levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
240
        if(levlCoeffs[i] == 17)
241
            levlCoeffs[i] += get_bits(&q->gb, 4);
242
    }
243
}
244

    
245
static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
246
                                         float* flcoeffs2)
247
{
248
    int i, level;
249
    float tmp, tmp2;
250
    //maybe some frequency division thingy
251

    
252
    flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
253
    flcoeffs2[0] = log(flcoeffs1[0])/log(2);
254
    tmp = flcoeffs1[0];
255
    tmp2 = flcoeffs2[0];
256

    
257
    for(i = 1; i < BANDS; i++) {
258
        level = levlCoeffBuf[i];
259
        if (level == 16) {
260
            flcoeffs1[i] = 1.0;
261
            flcoeffs2[i] = 0.0;
262
        } else {
263
            if (level < 17)
264
                level -=7;
265
            else if (level <= 24)
266
                level -=32;
267
            else
268
                level -=16;
269

    
270
            tmp  *= imc_exp_tab[15 + level];
271
            tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
272
            flcoeffs1[i] = tmp;
273
            flcoeffs2[i] = tmp2;
274
        }
275
    }
276
}
277

    
278

    
279
static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
280
                                          float* flcoeffs2) {
281
    int i;
282
        //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
283
        //      and flcoeffs2 old scale factors
284
        //      might be incomplete due to a missing table that is in the binary code
285
    for(i = 0; i < BANDS; i++) {
286
        flcoeffs1[i] = 0;
287
        if(levlCoeffBuf[i] < 16) {
288
            flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
289
            flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
290
        } else {
291
            flcoeffs1[i] = old_floor[i];
292
        }
293
    }
294
}
295

    
296
/**
297
 * Perform bit allocation depending on bits available
298
 */
299
static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
300
    int i, j;
301
    const float limit = -1.e20;
302
    float highest = 0.0;
303
    int indx;
304
    int t1 = 0;
305
    int t2 = 1;
306
    float summa = 0.0;
307
    int iacc = 0;
308
    int summer = 0;
309
    int rres, cwlen;
310
    float lowest = 1.e10;
311
    int low_indx = 0;
312
    float workT[32];
313
    int flg;
314
    int found_indx = 0;
315

    
316
    for(i = 0; i < BANDS; i++)
317
        highest = FFMAX(highest, q->flcoeffs1[i]);
318

    
319
    for(i = 0; i < BANDS-1; i++) {
320
        q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
321
    }
322
    q->flcoeffs4[BANDS - 1] = limit;
323

    
324
    highest = highest * 0.25;
325

    
326
    for(i = 0; i < BANDS; i++) {
327
        indx = -1;
328
        if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
329
            indx = 0;
330

    
331
        if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
332
            indx = 1;
333

    
334
        if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
335
            indx = 2;
336

    
337
        if (indx == -1)
338
            return -1;
339

    
340
        q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
341
    }
342

    
343
    if (stream_format_code & 0x2) {
344
        q->flcoeffs4[0] = limit;
345
        q->flcoeffs4[1] = limit;
346
        q->flcoeffs4[2] = limit;
347
        q->flcoeffs4[3] = limit;
348
    }
349

    
350
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
351
        iacc += q->bandWidthT[i];
352
        summa += q->bandWidthT[i] * q->flcoeffs4[i];
353
    }
354
    q->bandWidthT[BANDS-1] = 0;
355
    summa = (summa * 0.5 - freebits) / iacc;
356

    
357

    
358
    for(i = 0; i < BANDS/2; i++) {
359
        rres = summer - freebits;
360
        if((rres >= -8) && (rres <= 8)) break;
361

    
362
        summer = 0;
363
        iacc = 0;
364

    
365
        for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
366
            cwlen = av_clipf(((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
367

    
368
            q->bitsBandT[j] = cwlen;
369
            summer += q->bandWidthT[j] * cwlen;
370

    
371
            if (cwlen > 0)
372
                iacc += q->bandWidthT[j];
373
        }
374

    
375
        flg = t2;
376
        t2 = 1;
377
        if (freebits < summer)
378
            t2 = -1;
379
        if (i == 0)
380
            flg = t2;
381
        if(flg != t2)
382
            t1++;
383

    
384
        summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
385
    }
386

    
387
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
388
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
389
            q->CWlengthT[j] = q->bitsBandT[i];
390
    }
391

    
392
    if (freebits > summer) {
393
        for(i = 0; i < BANDS; i++) {
394
            workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
395
        }
396

    
397
        highest = 0.0;
398

    
399
        do{
400
            if (highest <= -1.e20)
401
                break;
402

    
403
            found_indx = 0;
404
            highest = -1.e20;
405

    
406
            for(i = 0; i < BANDS; i++) {
407
                if (workT[i] > highest) {
408
                    highest = workT[i];
409
                    found_indx = i;
410
                }
411
            }
412

    
413
            if (highest > -1.e20) {
414
                workT[found_indx] -= 2.0;
415
                if (++(q->bitsBandT[found_indx]) == 6)
416
                    workT[found_indx] = -1.e20;
417

    
418
                for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
419
                    q->CWlengthT[j]++;
420
                    summer++;
421
                }
422
            }
423
        }while (freebits > summer);
424
    }
425
    if (freebits < summer) {
426
        for(i = 0; i < BANDS; i++) {
427
            workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
428
        }
429
        if (stream_format_code & 0x2) {
430
            workT[0] = 1.e20;
431
            workT[1] = 1.e20;
432
            workT[2] = 1.e20;
433
            workT[3] = 1.e20;
434
        }
435
        while (freebits < summer){
436
            lowest = 1.e10;
437
            low_indx = 0;
438
            for(i = 0; i < BANDS; i++) {
439
                if (workT[i] < lowest) {
440
                    lowest = workT[i];
441
                    low_indx = i;
442
                }
443
            }
444
            //if(lowest >= 1.e10) break;
445
            workT[low_indx] = lowest + 2.0;
446

    
447
            if (!(--q->bitsBandT[low_indx]))
448
                workT[low_indx] = 1.e20;
449

    
450
            for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
451
                if(q->CWlengthT[j] > 0){
452
                    q->CWlengthT[j]--;
453
                    summer--;
454
                }
455
            }
456
        }
457
    }
458
    return 0;
459
}
460

    
461
static void imc_get_skip_coeff(IMCContext* q) {
462
    int i, j;
463

    
464
    memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
465
    memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
466
    for(i = 0; i < BANDS; i++) {
467
        if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
468
            continue;
469

    
470
        if (!q->skipFlagRaw[i]) {
471
            q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
472

    
473
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
474
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
475
                    q->skipFlagCount[i]++;
476
            }
477
        } else {
478
            for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
479
                if(!get_bits1(&q->gb)){//0
480
                    q->skipFlagBits[i]++;
481
                    q->skipFlags[j]=1;
482
                    q->skipFlags[j+1]=1;
483
                    q->skipFlagCount[i] += 2;
484
                }else{
485
                    if(get_bits1(&q->gb)){//11
486
                        q->skipFlagBits[i] +=2;
487
                        q->skipFlags[j]=0;
488
                        q->skipFlags[j+1]=1;
489
                        q->skipFlagCount[i]++;
490
                    }else{
491
                        q->skipFlagBits[i] +=3;
492
                        q->skipFlags[j+1]=0;
493
                        if(!get_bits1(&q->gb)){//100
494
                            q->skipFlags[j]=1;
495
                            q->skipFlagCount[i]++;
496
                        }else{//101
497
                            q->skipFlags[j]=0;
498
                        }
499
                    }
500
                }
501
            }
502

    
503
            if (j < band_tab[i+1]) {
504
                q->skipFlagBits[i]++;
505
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
506
                    q->skipFlagCount[i]++;
507
            }
508
        }
509
    }
510
}
511

    
512
/**
513
 * Increase highest' band coefficient sizes as some bits won't be used
514
 */
515
static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
516
    float workT[32];
517
    int corrected = 0;
518
    int i, j;
519
    float highest = 0;
520
    int found_indx=0;
521

    
522
    for(i = 0; i < BANDS; i++) {
523
        workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
524
    }
525

    
526
    while (corrected < summer) {
527
        if(highest <= -1.e20)
528
            break;
529

    
530
        highest = -1.e20;
531

    
532
        for(i = 0; i < BANDS; i++) {
533
            if (workT[i] > highest) {
534
                highest = workT[i];
535
                found_indx = i;
536
            }
537
        }
538

    
539
        if (highest > -1.e20) {
540
            workT[found_indx] -= 2.0;
541
            if (++(q->bitsBandT[found_indx]) == 6)
542
                workT[found_indx] = -1.e20;
543

    
544
            for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
545
                if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
546
                    q->CWlengthT[j]++;
547
                    corrected++;
548
                }
549
            }
550
        }
551
    }
552
}
553

    
554
static void imc_imdct256(IMCContext *q) {
555
    int i;
556
    float re, im;
557

    
558
    /* prerotation */
559
    for(i=0; i < COEFFS/2; i++){
560
        q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
561
                           (q->pre_coef2[i] * q->CWdecoded[i*2]);
562
        q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
563
                           (q->pre_coef1[i] * q->CWdecoded[i*2]);
564
    }
565

    
566
    /* FFT */
567
    ff_fft_permute(&q->fft, q->samples);
568
    ff_fft_calc (&q->fft, q->samples);
569

    
570
    /* postrotation, window and reorder */
571
    for(i = 0; i < COEFFS/2; i++){
572
        re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
573
        im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
574
        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);
575
        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);
576
        q->last_fft_im[i] = im;
577
    }
578
}
579

    
580
static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
581
    int i, j;
582
    int middle_value, cw_len, max_size;
583
    const float* quantizer;
584

    
585
    for(i = 0; i < BANDS; i++) {
586
        for(j = band_tab[i]; j < band_tab[i+1]; j++) {
587
            q->CWdecoded[j] = 0;
588
            cw_len = q->CWlengthT[j];
589

    
590
            if (cw_len <= 0 || q->skipFlags[j])
591
                continue;
592

    
593
            max_size = 1 << cw_len;
594
            middle_value = max_size >> 1;
595

    
596
            if (q->codewords[j] >= max_size || q->codewords[j] < 0)
597
                return -1;
598

    
599
            if (cw_len >= 4){
600
                quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
601
                if (q->codewords[j] >= middle_value)
602
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
603
                else
604
                    q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
605
            }else{
606
                quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
607
                if (q->codewords[j] >= middle_value)
608
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
609
                else
610
                    q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
611
            }
612
        }
613
    }
614
    return 0;
615
}
616

    
617

    
618
static int imc_get_coeffs (IMCContext* q) {
619
    int i, j, cw_len, cw;
620

    
621
    for(i = 0; i < BANDS; i++) {
622
        if(!q->sumLenArr[i]) continue;
623
        if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
624
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
625
                cw_len = q->CWlengthT[j];
626
                cw = 0;
627

    
628
                if (get_bits_count(&q->gb) + cw_len > 512){
629
//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
630
                    return -1;
631
                }
632

    
633
                if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
634
                    cw = get_bits(&q->gb, cw_len);
635

    
636
                q->codewords[j] = cw;
637
            }
638
        }
639
    }
640
    return 0;
641
}
642

    
643
static int imc_decode_frame(AVCodecContext * avctx,
644
                            void *data, int *data_size,
645
                            AVPacket *avpkt)
646
{
647
    const uint8_t *buf = avpkt->data;
648
    int buf_size = avpkt->size;
649

    
650
    IMCContext *q = avctx->priv_data;
651

    
652
    int stream_format_code;
653
    int imc_hdr, i, j;
654
    int flag;
655
    int bits, summer;
656
    int counter, bitscount;
657
    uint16_t buf16[IMC_BLOCK_SIZE / 2];
658

    
659
    if (buf_size < IMC_BLOCK_SIZE) {
660
        av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
661
        return -1;
662
    }
663
    for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
664
        buf16[i] = av_bswap16(((const uint16_t*)buf)[i]);
665

    
666
    q->out_samples = data;
667
    init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
668

    
669
    /* Check the frame header */
670
    imc_hdr = get_bits(&q->gb, 9);
671
    if (imc_hdr != IMC_FRAME_ID) {
672
        av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
673
        av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
674
        return -1;
675
    }
676
    stream_format_code = get_bits(&q->gb, 3);
677

    
678
    if(stream_format_code & 1){
679
        av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
680
        return -1;
681
    }
682

    
683
//    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
684

    
685
    if (stream_format_code & 0x04)
686
        q->decoder_reset = 1;
687

    
688
    if(q->decoder_reset) {
689
        memset(q->out_samples, 0, sizeof(q->out_samples));
690
        for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
691
        for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
692
        q->decoder_reset = 0;
693
    }
694

    
695
    flag = get_bits1(&q->gb);
696
    imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
697

    
698
    if (stream_format_code & 0x4)
699
        imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
700
    else
701
        imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);
702

    
703
    memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
704

    
705
    counter = 0;
706
    for (i=0 ; i<BANDS ; i++) {
707
        if (q->levlCoeffBuf[i] == 16) {
708
            q->bandWidthT[i] = 0;
709
            counter++;
710
        } else
711
            q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
712
    }
713
    memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
714
    for(i = 0; i < BANDS-1; i++) {
715
        if (q->bandWidthT[i])
716
            q->bandFlagsBuf[i] = get_bits1(&q->gb);
717
    }
718

    
719
    imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);
720

    
721
    bitscount = 0;
722
    /* first 4 bands will be assigned 5 bits per coefficient */
723
    if (stream_format_code & 0x2) {
724
        bitscount += 15;
725

    
726
        q->bitsBandT[0] = 5;
727
        q->CWlengthT[0] = 5;
728
        q->CWlengthT[1] = 5;
729
        q->CWlengthT[2] = 5;
730
        for(i = 1; i < 4; i++){
731
            bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
732
            q->bitsBandT[i] = bits;
733
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
734
                q->CWlengthT[j] = bits;
735
                bitscount += bits;
736
            }
737
        }
738
    }
739

    
740
    if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
741
        av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
742
        q->decoder_reset = 1;
743
        return -1;
744
    }
745

    
746
    for(i = 0; i < BANDS; i++) {
747
        q->sumLenArr[i] = 0;
748
        q->skipFlagRaw[i] = 0;
749
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
750
            q->sumLenArr[i] += q->CWlengthT[j];
751
        if (q->bandFlagsBuf[i])
752
            if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
753
                q->skipFlagRaw[i] = 1;
754
    }
755

    
756
    imc_get_skip_coeff(q);
757

    
758
    for(i = 0; i < BANDS; i++) {
759
        q->flcoeffs6[i] = q->flcoeffs1[i];
760
        /* band has flag set and at least one coded coefficient */
761
        if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
762
                q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
763
                                   q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
764
        }
765
    }
766

    
767
    /* calculate bits left, bits needed and adjust bit allocation */
768
    bits = summer = 0;
769

    
770
    for(i = 0; i < BANDS; i++) {
771
        if (q->bandFlagsBuf[i]) {
772
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
773
                if(q->skipFlags[j]) {
774
                    summer += q->CWlengthT[j];
775
                    q->CWlengthT[j] = 0;
776
                }
777
            }
778
            bits += q->skipFlagBits[i];
779
            summer -= q->skipFlagBits[i];
780
        }
781
    }
782
    imc_adjust_bit_allocation(q, summer);
783

    
784
    for(i = 0; i < BANDS; i++) {
785
        q->sumLenArr[i] = 0;
786

    
787
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
788
            if (!q->skipFlags[j])
789
                q->sumLenArr[i] += q->CWlengthT[j];
790
    }
791

    
792
    memset(q->codewords, 0, sizeof(q->codewords));
793

    
794
    if(imc_get_coeffs(q) < 0) {
795
        av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
796
        q->decoder_reset = 1;
797
        return 0;
798
    }
799

    
800
    if(inverse_quant_coeff(q, stream_format_code) < 0) {
801
        av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
802
        q->decoder_reset = 1;
803
        return 0;
804
    }
805

    
806
    memset(q->skipFlags, 0, sizeof(q->skipFlags));
807

    
808
    imc_imdct256(q);
809

    
810
    *data_size = COEFFS * sizeof(float);
811

    
812
    return IMC_BLOCK_SIZE;
813
}
814

    
815

    
816
static av_cold int imc_decode_close(AVCodecContext * avctx)
817
{
818
    IMCContext *q = avctx->priv_data;
819

    
820
    ff_fft_end(&q->fft);
821
    return 0;
822
}
823

    
824

    
825
AVCodec ff_imc_decoder = {
826
    .name = "imc",
827
    .type = AVMEDIA_TYPE_AUDIO,
828
    .id = CODEC_ID_IMC,
829
    .priv_data_size = sizeof(IMCContext),
830
    .init = imc_decode_init,
831
    .close = imc_decode_close,
832
    .decode = imc_decode_frame,
833
    .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
834
};