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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
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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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 * FFmpeg 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 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
/**
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 *  @file libavcodec/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

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

    
37
#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"
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 {
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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];
58

    
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    /** 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;
82
    int decoder_reset;
83
    float one_div_log2;
84

    
85
    DSPContext dsp;
86
    FFTContext fft;
87
    DECLARE_ALIGNED(16, FFTComplex, samples)[COEFFS/2];
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    DECLARE_ALIGNED(16, float, out_samples)[COEFFS];
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} IMCContext;
90

    
91
static VLC huffman_vlc[4][4];
92

    
93
#define VLC_TABLES_SIZE 9512
94

    
95
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};
98

    
99
static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];
100

    
101
static av_cold int imc_decode_init(AVCodecContext * avctx)
102
{
103
    int i, j;
104
    IMCContext *q = avctx->priv_data;
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    double r1, r2;
106

    
107
    q->decoder_reset = 1;
108

    
109
    for(i = 0; i < BANDS; i++)
110
        q->old_floor[i] = 1.0;
111

    
112
    /* 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++){
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        q->post_cos[i] = cos(i / 256.0 * M_PI);
118
        q->post_sin[i] = sin(i / 256.0 * M_PI);
119

    
120
        r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
121
        r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
122

    
123
        if (i & 0x1)
124
        {
125
            q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
126
            q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
127
        }
128
        else
129
        {
130
            q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
131
            q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
132
        }
133

    
134
        q->last_fft_im[i] = 0;
135
    }
136

    
137
    /* Generate a square root table */
138

    
139
    for(i = 0; i < 30; i++) {
140
        q->sqrt_tab[i] = sqrt(i);
141
    }
142

    
143
    /* initialize the VLC tables */
144
    for(i = 0; i < 4 ; i++) {
145
        for(j = 0; j < 4; j++) {
146
            huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
147
            huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
148
            init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
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                     imc_huffman_lens[i][j], 1, 1,
150
                     imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
151
        }
152
    }
153
    q->one_div_log2 = 1/log(2);
154

    
155
    ff_fft_init(&q->fft, 7, 1);
156
    dsputil_init(&q->dsp, avctx);
157
    avctx->sample_fmt = SAMPLE_FMT_S16;
158
    avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;
159
    return 0;
160
}
161

    
162
static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
163
                                float* flcoeffs3, float* flcoeffs5)
164
{
165
    float   workT1[BANDS];
166
    float   workT2[BANDS];
167
    float   workT3[BANDS];
168
    float   snr_limit = 1.e-30;
169
    float   accum = 0.0;
170
    int i, cnt2;
171

    
172
    for(i = 0; i < BANDS; i++) {
173
        flcoeffs5[i] = workT2[i] = 0.0;
174
        if (bandWidthT[i]){
175
            workT1[i] = flcoeffs1[i] * flcoeffs1[i];
176
            flcoeffs3[i] = 2.0 * flcoeffs2[i];
177
        } else {
178
            workT1[i] = 0.0;
179
            flcoeffs3[i] = -30000.0;
180
        }
181
        workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
182
        if (workT3[i] <= snr_limit)
183
            workT3[i] = 0.0;
184
    }
185

    
186
    for(i = 0; i < BANDS; i++) {
187
        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];
190
    }
191

    
192
    for(i = 1; i < BANDS; i++) {
193
        accum = (workT2[i-1] + accum) * imc_weights1[i-1];
194
        flcoeffs5[i] += accum;
195
    }
196

    
197
    for(i = 0; i < BANDS; i++)
198
        workT2[i] = 0.0;
199

    
200
    for(i = 0; i < BANDS; i++) {
201
        for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
202
            flcoeffs5[cnt2] += workT3[i];
203
        workT2[cnt2+1] += workT3[i];
204
    }
205

    
206
    accum = 0.0;
207

    
208
    for(i = BANDS-2; i >= 0; i--) {
209
        accum = (workT2[i+1] + accum) * imc_weights2[i];
210
        flcoeffs5[i] += accum;
211
        //there is missing code here, but it seems to never be triggered
212
    }
213
}
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215

    
216
static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
217
{
218
    int i;
219
    VLC *hufftab[4];
220
    int start = 0;
221
    const uint8_t *cb_sel;
222
    int s;
223

    
224
    s = stream_format_code >> 1;
225
    hufftab[0] = &huffman_vlc[s][0];
226
    hufftab[1] = &huffman_vlc[s][1];
227
    hufftab[2] = &huffman_vlc[s][2];
228
    hufftab[3] = &huffman_vlc[s][3];
229
    cb_sel = imc_cb_select[s];
230

    
231
    if(stream_format_code & 4)
232
        start = 1;
233
    if(start)
234
        levlCoeffs[0] = get_bits(&q->gb, 7);
235
    for(i = start; i < BANDS; i++){
236
        levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
237
        if(levlCoeffs[i] == 17)
238
            levlCoeffs[i] += get_bits(&q->gb, 4);
239
    }
240
}
241

    
242
static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
243
                                         float* flcoeffs2)
244
{
245
    int i, level;
246
    float tmp, tmp2;
247
    //maybe some frequency division thingy
248

    
249
    flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
250
    flcoeffs2[0] = log(flcoeffs1[0])/log(2);
251
    tmp = flcoeffs1[0];
252
    tmp2 = flcoeffs2[0];
253

    
254
    for(i = 1; i < BANDS; i++) {
255
        level = levlCoeffBuf[i];
256
        if (level == 16) {
257
            flcoeffs1[i] = 1.0;
258
            flcoeffs2[i] = 0.0;
259
        } else {
260
            if (level < 17)
261
                level -=7;
262
            else if (level <= 24)
263
                level -=32;
264
            else
265
                level -=16;
266

    
267
            tmp  *= imc_exp_tab[15 + level];
268
            tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
269
            flcoeffs1[i] = tmp;
270
            flcoeffs2[i] = tmp2;
271
        }
272
    }
273
}
274

    
275

    
276
static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
277
                                          float* flcoeffs2) {
278
    int i;
279
        //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
280
        //      and flcoeffs2 old scale factors
281
        //      might be incomplete due to a missing table that is in the binary code
282
    for(i = 0; i < BANDS; i++) {
283
        flcoeffs1[i] = 0;
284
        if(levlCoeffBuf[i] < 16) {
285
            flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
286
            flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
287
        } else {
288
            flcoeffs1[i] = old_floor[i];
289
        }
290
    }
291
}
292

    
293
/**
294
 * Perform bit allocation depending on bits available
295
 */
296
static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
297
    int i, j;
298
    const float limit = -1.e20;
299
    float highest = 0.0;
300
    int indx;
301
    int t1 = 0;
302
    int t2 = 1;
303
    float summa = 0.0;
304
    int iacc = 0;
305
    int summer = 0;
306
    int rres, cwlen;
307
    float lowest = 1.e10;
308
    int low_indx = 0;
309
    float workT[32];
310
    int flg;
311
    int found_indx = 0;
312

    
313
    for(i = 0; i < BANDS; i++)
314
        highest = FFMAX(highest, q->flcoeffs1[i]);
315

    
316
    for(i = 0; i < BANDS-1; i++) {
317
        q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
318
    }
319
    q->flcoeffs4[BANDS - 1] = limit;
320

    
321
    highest = highest * 0.25;
322

    
323
    for(i = 0; i < BANDS; i++) {
324
        indx = -1;
325
        if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
326
            indx = 0;
327

    
328
        if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
329
            indx = 1;
330

    
331
        if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
332
            indx = 2;
333

    
334
        if (indx == -1)
335
            return -1;
336

    
337
        q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
338
    }
339

    
340
    if (stream_format_code & 0x2) {
341
        q->flcoeffs4[0] = limit;
342
        q->flcoeffs4[1] = limit;
343
        q->flcoeffs4[2] = limit;
344
        q->flcoeffs4[3] = limit;
345
    }
346

    
347
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
348
        iacc += q->bandWidthT[i];
349
        summa += q->bandWidthT[i] * q->flcoeffs4[i];
350
    }
351
    q->bandWidthT[BANDS-1] = 0;
352
    summa = (summa * 0.5 - freebits) / iacc;
353

    
354

    
355
    for(i = 0; i < BANDS/2; i++) {
356
        rres = summer - freebits;
357
        if((rres >= -8) && (rres <= 8)) break;
358

    
359
        summer = 0;
360
        iacc = 0;
361

    
362
        for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
363
            cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
364

    
365
            q->bitsBandT[j] = cwlen;
366
            summer += q->bandWidthT[j] * cwlen;
367

    
368
            if (cwlen > 0)
369
                iacc += q->bandWidthT[j];
370
        }
371

    
372
        flg = t2;
373
        t2 = 1;
374
        if (freebits < summer)
375
            t2 = -1;
376
        if (i == 0)
377
            flg = t2;
378
        if(flg != t2)
379
            t1++;
380

    
381
        summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
382
    }
383

    
384
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
385
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
386
            q->CWlengthT[j] = q->bitsBandT[i];
387
    }
388

    
389
    if (freebits > summer) {
390
        for(i = 0; i < BANDS; i++) {
391
            workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
392
        }
393

    
394
        highest = 0.0;
395

    
396
        do{
397
            if (highest <= -1.e20)
398
                break;
399

    
400
            found_indx = 0;
401
            highest = -1.e20;
402

    
403
            for(i = 0; i < BANDS; i++) {
404
                if (workT[i] > highest) {
405
                    highest = workT[i];
406
                    found_indx = i;
407
                }
408
            }
409

    
410
            if (highest > -1.e20) {
411
                workT[found_indx] -= 2.0;
412
                if (++(q->bitsBandT[found_indx]) == 6)
413
                    workT[found_indx] = -1.e20;
414

    
415
                for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
416
                    q->CWlengthT[j]++;
417
                    summer++;
418
                }
419
            }
420
        }while (freebits > summer);
421
    }
422
    if (freebits < summer) {
423
        for(i = 0; i < BANDS; i++) {
424
            workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
425
        }
426
        if (stream_format_code & 0x2) {
427
            workT[0] = 1.e20;
428
            workT[1] = 1.e20;
429
            workT[2] = 1.e20;
430
            workT[3] = 1.e20;
431
        }
432
        while (freebits < summer){
433
            lowest = 1.e10;
434
            low_indx = 0;
435
            for(i = 0; i < BANDS; i++) {
436
                if (workT[i] < lowest) {
437
                    lowest = workT[i];
438
                    low_indx = i;
439
                }
440
            }
441
            //if(lowest >= 1.e10) break;
442
            workT[low_indx] = lowest + 2.0;
443

    
444
            if (!(--q->bitsBandT[low_indx]))
445
                workT[low_indx] = 1.e20;
446

    
447
            for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
448
                if(q->CWlengthT[j] > 0){
449
                    q->CWlengthT[j]--;
450
                    summer--;
451
                }
452
            }
453
        }
454
    }
455
    return 0;
456
}
457

    
458
static void imc_get_skip_coeff(IMCContext* q) {
459
    int i, j;
460

    
461
    memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
462
    memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
463
    for(i = 0; i < BANDS; i++) {
464
        if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
465
            continue;
466

    
467
        if (!q->skipFlagRaw[i]) {
468
            q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
469

    
470
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
471
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
472
                    q->skipFlagCount[i]++;
473
            }
474
        } else {
475
            for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
476
                if(!get_bits1(&q->gb)){//0
477
                    q->skipFlagBits[i]++;
478
                    q->skipFlags[j]=1;
479
                    q->skipFlags[j+1]=1;
480
                    q->skipFlagCount[i] += 2;
481
                }else{
482
                    if(get_bits1(&q->gb)){//11
483
                        q->skipFlagBits[i] +=2;
484
                        q->skipFlags[j]=0;
485
                        q->skipFlags[j+1]=1;
486
                        q->skipFlagCount[i]++;
487
                    }else{
488
                        q->skipFlagBits[i] +=3;
489
                        q->skipFlags[j+1]=0;
490
                        if(!get_bits1(&q->gb)){//100
491
                            q->skipFlags[j]=1;
492
                            q->skipFlagCount[i]++;
493
                        }else{//101
494
                            q->skipFlags[j]=0;
495
                        }
496
                    }
497
                }
498
            }
499

    
500
            if (j < band_tab[i+1]) {
501
                q->skipFlagBits[i]++;
502
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
503
                    q->skipFlagCount[i]++;
504
            }
505
        }
506
    }
507
}
508

    
509
/**
510
 * Increase highest' band coefficient sizes as some bits won't be used
511
 */
512
static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
513
    float workT[32];
514
    int corrected = 0;
515
    int i, j;
516
    float highest = 0;
517
    int found_indx=0;
518

    
519
    for(i = 0; i < BANDS; i++) {
520
        workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
521
    }
522

    
523
    while (corrected < summer) {
524
        if(highest <= -1.e20)
525
            break;
526

    
527
        highest = -1.e20;
528

    
529
        for(i = 0; i < BANDS; i++) {
530
            if (workT[i] > highest) {
531
                highest = workT[i];
532
                found_indx = i;
533
            }
534
        }
535

    
536
        if (highest > -1.e20) {
537
            workT[found_indx] -= 2.0;
538
            if (++(q->bitsBandT[found_indx]) == 6)
539
                workT[found_indx] = -1.e20;
540

    
541
            for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
542
                if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
543
                    q->CWlengthT[j]++;
544
                    corrected++;
545
                }
546
            }
547
        }
548
    }
549
}
550

    
551
static void imc_imdct256(IMCContext *q) {
552
    int i;
553
    float re, im;
554

    
555
    /* prerotation */
556
    for(i=0; i < COEFFS/2; i++){
557
        q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
558
                           (q->pre_coef2[i] * q->CWdecoded[i*2]);
559
        q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
560
                           (q->pre_coef1[i] * q->CWdecoded[i*2]);
561
    }
562

    
563
    /* FFT */
564
    ff_fft_permute(&q->fft, q->samples);
565
    ff_fft_calc (&q->fft, q->samples);
566

    
567
    /* postrotation, window and reorder */
568
    for(i = 0; i < COEFFS/2; i++){
569
        re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
570
        im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
571
        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);
572
        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);
573
        q->last_fft_im[i] = im;
574
    }
575
}
576

    
577
static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
578
    int i, j;
579
    int middle_value, cw_len, max_size;
580
    const float* quantizer;
581

    
582
    for(i = 0; i < BANDS; i++) {
583
        for(j = band_tab[i]; j < band_tab[i+1]; j++) {
584
            q->CWdecoded[j] = 0;
585
            cw_len = q->CWlengthT[j];
586

    
587
            if (cw_len <= 0 || q->skipFlags[j])
588
                continue;
589

    
590
            max_size = 1 << cw_len;
591
            middle_value = max_size >> 1;
592

    
593
            if (q->codewords[j] >= max_size || q->codewords[j] < 0)
594
                return -1;
595

    
596
            if (cw_len >= 4){
597
                quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
598
                if (q->codewords[j] >= middle_value)
599
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
600
                else
601
                    q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
602
            }else{
603
                quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
604
                if (q->codewords[j] >= middle_value)
605
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
606
                else
607
                    q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
608
            }
609
        }
610
    }
611
    return 0;
612
}
613

    
614

    
615
static int imc_get_coeffs (IMCContext* q) {
616
    int i, j, cw_len, cw;
617

    
618
    for(i = 0; i < BANDS; i++) {
619
        if(!q->sumLenArr[i]) continue;
620
        if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
621
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
622
                cw_len = q->CWlengthT[j];
623
                cw = 0;
624

    
625
                if (get_bits_count(&q->gb) + cw_len > 512){
626
//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
627
                    return -1;
628
                }
629

    
630
                if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
631
                    cw = get_bits(&q->gb, cw_len);
632

    
633
                q->codewords[j] = cw;
634
            }
635
        }
636
    }
637
    return 0;
638
}
639

    
640
static int imc_decode_frame(AVCodecContext * avctx,
641
                            void *data, int *data_size,
642
                            AVPacket *avpkt)
643
{
644
    const uint8_t *buf = avpkt->data;
645
    int buf_size = avpkt->size;
646

    
647
    IMCContext *q = avctx->priv_data;
648

    
649
    int stream_format_code;
650
    int imc_hdr, i, j;
651
    int flag;
652
    int bits, summer;
653
    int counter, bitscount;
654
    uint16_t buf16[IMC_BLOCK_SIZE / 2];
655

    
656
    if (buf_size < IMC_BLOCK_SIZE) {
657
        av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
658
        return -1;
659
    }
660
    for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
661
        buf16[i] = bswap_16(((const uint16_t*)buf)[i]);
662

    
663
    init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
664

    
665
    /* Check the frame header */
666
    imc_hdr = get_bits(&q->gb, 9);
667
    if (imc_hdr != IMC_FRAME_ID) {
668
        av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
669
        av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
670
        return -1;
671
    }
672
    stream_format_code = get_bits(&q->gb, 3);
673

    
674
    if(stream_format_code & 1){
675
        av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
676
        return -1;
677
    }
678

    
679
//    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
680

    
681
    if (stream_format_code & 0x04)
682
        q->decoder_reset = 1;
683

    
684
    if(q->decoder_reset) {
685
        memset(q->out_samples, 0, sizeof(q->out_samples));
686
        for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
687
        for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
688
        q->decoder_reset = 0;
689
    }
690

    
691
    flag = get_bits1(&q->gb);
692
    imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
693

    
694
    if (stream_format_code & 0x4)
695
        imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
696
    else
697
        imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);
698

    
699
    memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
700

    
701
    counter = 0;
702
    for (i=0 ; i<BANDS ; i++) {
703
        if (q->levlCoeffBuf[i] == 16) {
704
            q->bandWidthT[i] = 0;
705
            counter++;
706
        } else
707
            q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
708
    }
709
    memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
710
    for(i = 0; i < BANDS-1; i++) {
711
        if (q->bandWidthT[i])
712
            q->bandFlagsBuf[i] = get_bits1(&q->gb);
713
    }
714

    
715
    imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);
716

    
717
    bitscount = 0;
718
    /* first 4 bands will be assigned 5 bits per coefficient */
719
    if (stream_format_code & 0x2) {
720
        bitscount += 15;
721

    
722
        q->bitsBandT[0] = 5;
723
        q->CWlengthT[0] = 5;
724
        q->CWlengthT[1] = 5;
725
        q->CWlengthT[2] = 5;
726
        for(i = 1; i < 4; i++){
727
            bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
728
            q->bitsBandT[i] = bits;
729
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
730
                q->CWlengthT[j] = bits;
731
                bitscount += bits;
732
            }
733
        }
734
    }
735

    
736
    if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
737
        av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
738
        q->decoder_reset = 1;
739
        return -1;
740
    }
741

    
742
    for(i = 0; i < BANDS; i++) {
743
        q->sumLenArr[i] = 0;
744
        q->skipFlagRaw[i] = 0;
745
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
746
            q->sumLenArr[i] += q->CWlengthT[j];
747
        if (q->bandFlagsBuf[i])
748
            if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
749
                q->skipFlagRaw[i] = 1;
750
    }
751

    
752
    imc_get_skip_coeff(q);
753

    
754
    for(i = 0; i < BANDS; i++) {
755
        q->flcoeffs6[i] = q->flcoeffs1[i];
756
        /* band has flag set and at least one coded coefficient */
757
        if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
758
                q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
759
                                   q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
760
        }
761
    }
762

    
763
    /* calculate bits left, bits needed and adjust bit allocation */
764
    bits = summer = 0;
765

    
766
    for(i = 0; i < BANDS; i++) {
767
        if (q->bandFlagsBuf[i]) {
768
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
769
                if(q->skipFlags[j]) {
770
                    summer += q->CWlengthT[j];
771
                    q->CWlengthT[j] = 0;
772
                }
773
            }
774
            bits += q->skipFlagBits[i];
775
            summer -= q->skipFlagBits[i];
776
        }
777
    }
778
    imc_adjust_bit_allocation(q, summer);
779

    
780
    for(i = 0; i < BANDS; i++) {
781
        q->sumLenArr[i] = 0;
782

    
783
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
784
            if (!q->skipFlags[j])
785
                q->sumLenArr[i] += q->CWlengthT[j];
786
    }
787

    
788
    memset(q->codewords, 0, sizeof(q->codewords));
789

    
790
    if(imc_get_coeffs(q) < 0) {
791
        av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
792
        q->decoder_reset = 1;
793
        return 0;
794
    }
795

    
796
    if(inverse_quant_coeff(q, stream_format_code) < 0) {
797
        av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
798
        q->decoder_reset = 1;
799
        return 0;
800
    }
801

    
802
    memset(q->skipFlags, 0, sizeof(q->skipFlags));
803

    
804
    imc_imdct256(q);
805

    
806
    q->dsp.float_to_int16(data, q->out_samples, COEFFS);
807

    
808
    *data_size = COEFFS * sizeof(int16_t);
809

    
810
    return IMC_BLOCK_SIZE;
811
}
812

    
813

    
814
static av_cold int imc_decode_close(AVCodecContext * avctx)
815
{
816
    IMCContext *q = avctx->priv_data;
817

    
818
    ff_fft_end(&q->fft);
819
    return 0;
820
}
821

    
822

    
823
AVCodec imc_decoder = {
824
    .name = "imc",
825
    .type = CODEC_TYPE_AUDIO,
826
    .id = CODEC_ID_IMC,
827
    .priv_data_size = sizeof(IMCContext),
828
    .init = imc_decode_init,
829
    .close = imc_decode_close,
830
    .decode = imc_decode_frame,
831
    .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
832
};