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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

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

    
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#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"
42

    
43
#include "imcdata.h"
44

    
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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
49

    
50
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];
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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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    //@}
69

    
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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
80
    int codewords[COEFFS];     ///< raw codewords read from bitstream
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    float sqrt_tab[30];
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    GetBitContext gb;
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
static VLC huffman_vlc[4][4];
93

    
94
#define VLC_TABLES_SIZE 9512
95

    
96
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};
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static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];
101

    
102
static av_cold int imc_decode_init(AVCodecContext * avctx)
103
{
104
    int i, j;
105
    IMCContext *q = avctx->priv_data;
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    double r1, r2;
107

    
108
    q->decoder_reset = 1;
109

    
110
    for(i = 0; i < BANDS; i++)
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        q->old_floor[i] = 1.0;
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    /* 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++){
118
        q->post_cos[i] = cos(i / 256.0 * M_PI);
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        q->post_sin[i] = sin(i / 256.0 * M_PI);
120

    
121
        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);
123

    
124
        if (i & 0x1)
125
        {
126
            q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
127
            q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
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        }
129
        else
130
        {
131
            q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
132
            q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
133
        }
134

    
135
        q->last_fft_im[i] = 0;
136
    }
137

    
138
    /* Generate a square root table */
139

    
140
    for(i = 0; i < 30; i++) {
141
        q->sqrt_tab[i] = sqrt(i);
142
    }
143

    
144
    /* initialize the VLC tables */
145
    for(i = 0; i < 4 ; i++) {
146
        for(j = 0; j < 4; j++) {
147
            huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
148
            huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
149
            init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
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                     imc_huffman_lens[i][j], 1, 1,
151
                     imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
152
        }
153
    }
154
    q->one_div_log2 = 1/log(2);
155

    
156
    ff_fft_init(&q->fft, 7, 1);
157
    dsputil_init(&q->dsp, avctx);
158
    avctx->sample_fmt = SAMPLE_FMT_S16;
159
    avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;
160
    return 0;
161
}
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163
static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
164
                                float* flcoeffs3, float* flcoeffs5)
165
{
166
    float   workT1[BANDS];
167
    float   workT2[BANDS];
168
    float   workT3[BANDS];
169
    float   snr_limit = 1.e-30;
170
    float   accum = 0.0;
171
    int i, cnt2;
172

    
173
    for(i = 0; i < BANDS; i++) {
174
        flcoeffs5[i] = workT2[i] = 0.0;
175
        if (bandWidthT[i]){
176
            workT1[i] = flcoeffs1[i] * flcoeffs1[i];
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            flcoeffs3[i] = 2.0 * flcoeffs2[i];
178
        } else {
179
            workT1[i] = 0.0;
180
            flcoeffs3[i] = -30000.0;
181
        }
182
        workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
183
        if (workT3[i] <= snr_limit)
184
            workT3[i] = 0.0;
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    }
186

    
187
    for(i = 0; i < BANDS; i++) {
188
        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];
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    }
192

    
193
    for(i = 1; i < BANDS; i++) {
194
        accum = (workT2[i-1] + accum) * imc_weights1[i-1];
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        flcoeffs5[i] += accum;
196
    }
197

    
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    for(i = 0; i < BANDS; i++)
199
        workT2[i] = 0.0;
200

    
201
    for(i = 0; i < BANDS; i++) {
202
        for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
203
            flcoeffs5[cnt2] += workT3[i];
204
        workT2[cnt2+1] += workT3[i];
205
    }
206

    
207
    accum = 0.0;
208

    
209
    for(i = BANDS-2; i >= 0; i--) {
210
        accum = (workT2[i+1] + accum) * imc_weights2[i];
211
        flcoeffs5[i] += accum;
212
        //there is missing code here, but it seems to never be triggered
213
    }
214
}
215

    
216

    
217
static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
218
{
219
    int i;
220
    VLC *hufftab[4];
221
    int start = 0;
222
    const uint8_t *cb_sel;
223
    int s;
224

    
225
    s = stream_format_code >> 1;
226
    hufftab[0] = &huffman_vlc[s][0];
227
    hufftab[1] = &huffman_vlc[s][1];
228
    hufftab[2] = &huffman_vlc[s][2];
229
    hufftab[3] = &huffman_vlc[s][3];
230
    cb_sel = imc_cb_select[s];
231

    
232
    if(stream_format_code & 4)
233
        start = 1;
234
    if(start)
235
        levlCoeffs[0] = get_bits(&q->gb, 7);
236
    for(i = start; i < BANDS; i++){
237
        levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
238
        if(levlCoeffs[i] == 17)
239
            levlCoeffs[i] += get_bits(&q->gb, 4);
240
    }
241
}
242

    
243
static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
244
                                         float* flcoeffs2)
245
{
246
    int i, level;
247
    float tmp, tmp2;
248
    //maybe some frequency division thingy
249

    
250
    flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
251
    flcoeffs2[0] = log(flcoeffs1[0])/log(2);
252
    tmp = flcoeffs1[0];
253
    tmp2 = flcoeffs2[0];
254

    
255
    for(i = 1; i < BANDS; i++) {
256
        level = levlCoeffBuf[i];
257
        if (level == 16) {
258
            flcoeffs1[i] = 1.0;
259
            flcoeffs2[i] = 0.0;
260
        } else {
261
            if (level < 17)
262
                level -=7;
263
            else if (level <= 24)
264
                level -=32;
265
            else
266
                level -=16;
267

    
268
            tmp  *= imc_exp_tab[15 + level];
269
            tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
270
            flcoeffs1[i] = tmp;
271
            flcoeffs2[i] = tmp2;
272
        }
273
    }
274
}
275

    
276

    
277
static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
278
                                          float* flcoeffs2) {
279
    int i;
280
        //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
281
        //      and flcoeffs2 old scale factors
282
        //      might be incomplete due to a missing table that is in the binary code
283
    for(i = 0; i < BANDS; i++) {
284
        flcoeffs1[i] = 0;
285
        if(levlCoeffBuf[i] < 16) {
286
            flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
287
            flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
288
        } else {
289
            flcoeffs1[i] = old_floor[i];
290
        }
291
    }
292
}
293

    
294
/**
295
 * Perform bit allocation depending on bits available
296
 */
297
static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
298
    int i, j;
299
    const float limit = -1.e20;
300
    float highest = 0.0;
301
    int indx;
302
    int t1 = 0;
303
    int t2 = 1;
304
    float summa = 0.0;
305
    int iacc = 0;
306
    int summer = 0;
307
    int rres, cwlen;
308
    float lowest = 1.e10;
309
    int low_indx = 0;
310
    float workT[32];
311
    int flg;
312
    int found_indx = 0;
313

    
314
    for(i = 0; i < BANDS; i++)
315
        highest = FFMAX(highest, q->flcoeffs1[i]);
316

    
317
    for(i = 0; i < BANDS-1; i++) {
318
        q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
319
    }
320
    q->flcoeffs4[BANDS - 1] = limit;
321

    
322
    highest = highest * 0.25;
323

    
324
    for(i = 0; i < BANDS; i++) {
325
        indx = -1;
326
        if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
327
            indx = 0;
328

    
329
        if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
330
            indx = 1;
331

    
332
        if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
333
            indx = 2;
334

    
335
        if (indx == -1)
336
            return -1;
337

    
338
        q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
339
    }
340

    
341
    if (stream_format_code & 0x2) {
342
        q->flcoeffs4[0] = limit;
343
        q->flcoeffs4[1] = limit;
344
        q->flcoeffs4[2] = limit;
345
        q->flcoeffs4[3] = limit;
346
    }
347

    
348
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
349
        iacc += q->bandWidthT[i];
350
        summa += q->bandWidthT[i] * q->flcoeffs4[i];
351
    }
352
    q->bandWidthT[BANDS-1] = 0;
353
    summa = (summa * 0.5 - freebits) / iacc;
354

    
355

    
356
    for(i = 0; i < BANDS/2; i++) {
357
        rres = summer - freebits;
358
        if((rres >= -8) && (rres <= 8)) break;
359

    
360
        summer = 0;
361
        iacc = 0;
362

    
363
        for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
364
            cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
365

    
366
            q->bitsBandT[j] = cwlen;
367
            summer += q->bandWidthT[j] * cwlen;
368

    
369
            if (cwlen > 0)
370
                iacc += q->bandWidthT[j];
371
        }
372

    
373
        flg = t2;
374
        t2 = 1;
375
        if (freebits < summer)
376
            t2 = -1;
377
        if (i == 0)
378
            flg = t2;
379
        if(flg != t2)
380
            t1++;
381

    
382
        summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
383
    }
384

    
385
    for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
386
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
387
            q->CWlengthT[j] = q->bitsBandT[i];
388
    }
389

    
390
    if (freebits > summer) {
391
        for(i = 0; i < BANDS; i++) {
392
            workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
393
        }
394

    
395
        highest = 0.0;
396

    
397
        do{
398
            if (highest <= -1.e20)
399
                break;
400

    
401
            found_indx = 0;
402
            highest = -1.e20;
403

    
404
            for(i = 0; i < BANDS; i++) {
405
                if (workT[i] > highest) {
406
                    highest = workT[i];
407
                    found_indx = i;
408
                }
409
            }
410

    
411
            if (highest > -1.e20) {
412
                workT[found_indx] -= 2.0;
413
                if (++(q->bitsBandT[found_indx]) == 6)
414
                    workT[found_indx] = -1.e20;
415

    
416
                for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
417
                    q->CWlengthT[j]++;
418
                    summer++;
419
                }
420
            }
421
        }while (freebits > summer);
422
    }
423
    if (freebits < summer) {
424
        for(i = 0; i < BANDS; i++) {
425
            workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
426
        }
427
        if (stream_format_code & 0x2) {
428
            workT[0] = 1.e20;
429
            workT[1] = 1.e20;
430
            workT[2] = 1.e20;
431
            workT[3] = 1.e20;
432
        }
433
        while (freebits < summer){
434
            lowest = 1.e10;
435
            low_indx = 0;
436
            for(i = 0; i < BANDS; i++) {
437
                if (workT[i] < lowest) {
438
                    lowest = workT[i];
439
                    low_indx = i;
440
                }
441
            }
442
            //if(lowest >= 1.e10) break;
443
            workT[low_indx] = lowest + 2.0;
444

    
445
            if (!(--q->bitsBandT[low_indx]))
446
                workT[low_indx] = 1.e20;
447

    
448
            for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
449
                if(q->CWlengthT[j] > 0){
450
                    q->CWlengthT[j]--;
451
                    summer--;
452
                }
453
            }
454
        }
455
    }
456
    return 0;
457
}
458

    
459
static void imc_get_skip_coeff(IMCContext* q) {
460
    int i, j;
461

    
462
    memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
463
    memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
464
    for(i = 0; i < BANDS; i++) {
465
        if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
466
            continue;
467

    
468
        if (!q->skipFlagRaw[i]) {
469
            q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
470

    
471
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
472
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
473
                    q->skipFlagCount[i]++;
474
            }
475
        } else {
476
            for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
477
                if(!get_bits1(&q->gb)){//0
478
                    q->skipFlagBits[i]++;
479
                    q->skipFlags[j]=1;
480
                    q->skipFlags[j+1]=1;
481
                    q->skipFlagCount[i] += 2;
482
                }else{
483
                    if(get_bits1(&q->gb)){//11
484
                        q->skipFlagBits[i] +=2;
485
                        q->skipFlags[j]=0;
486
                        q->skipFlags[j+1]=1;
487
                        q->skipFlagCount[i]++;
488
                    }else{
489
                        q->skipFlagBits[i] +=3;
490
                        q->skipFlags[j+1]=0;
491
                        if(!get_bits1(&q->gb)){//100
492
                            q->skipFlags[j]=1;
493
                            q->skipFlagCount[i]++;
494
                        }else{//101
495
                            q->skipFlags[j]=0;
496
                        }
497
                    }
498
                }
499
            }
500

    
501
            if (j < band_tab[i+1]) {
502
                q->skipFlagBits[i]++;
503
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
504
                    q->skipFlagCount[i]++;
505
            }
506
        }
507
    }
508
}
509

    
510
/**
511
 * Increase highest' band coefficient sizes as some bits won't be used
512
 */
513
static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
514
    float workT[32];
515
    int corrected = 0;
516
    int i, j;
517
    float highest = 0;
518
    int found_indx=0;
519

    
520
    for(i = 0; i < BANDS; i++) {
521
        workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
522
    }
523

    
524
    while (corrected < summer) {
525
        if(highest <= -1.e20)
526
            break;
527

    
528
        highest = -1.e20;
529

    
530
        for(i = 0; i < BANDS; i++) {
531
            if (workT[i] > highest) {
532
                highest = workT[i];
533
                found_indx = i;
534
            }
535
        }
536

    
537
        if (highest > -1.e20) {
538
            workT[found_indx] -= 2.0;
539
            if (++(q->bitsBandT[found_indx]) == 6)
540
                workT[found_indx] = -1.e20;
541

    
542
            for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
543
                if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
544
                    q->CWlengthT[j]++;
545
                    corrected++;
546
                }
547
            }
548
        }
549
    }
550
}
551

    
552
static void imc_imdct256(IMCContext *q) {
553
    int i;
554
    float re, im;
555

    
556
    /* prerotation */
557
    for(i=0; i < COEFFS/2; i++){
558
        q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
559
                           (q->pre_coef2[i] * q->CWdecoded[i*2]);
560
        q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
561
                           (q->pre_coef1[i] * q->CWdecoded[i*2]);
562
    }
563

    
564
    /* FFT */
565
    ff_fft_permute(&q->fft, q->samples);
566
    ff_fft_calc (&q->fft, q->samples);
567

    
568
    /* postrotation, window and reorder */
569
    for(i = 0; i < COEFFS/2; i++){
570
        re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
571
        im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
572
        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);
573
        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);
574
        q->last_fft_im[i] = im;
575
    }
576
}
577

    
578
static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
579
    int i, j;
580
    int middle_value, cw_len, max_size;
581
    const float* quantizer;
582

    
583
    for(i = 0; i < BANDS; i++) {
584
        for(j = band_tab[i]; j < band_tab[i+1]; j++) {
585
            q->CWdecoded[j] = 0;
586
            cw_len = q->CWlengthT[j];
587

    
588
            if (cw_len <= 0 || q->skipFlags[j])
589
                continue;
590

    
591
            max_size = 1 << cw_len;
592
            middle_value = max_size >> 1;
593

    
594
            if (q->codewords[j] >= max_size || q->codewords[j] < 0)
595
                return -1;
596

    
597
            if (cw_len >= 4){
598
                quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
599
                if (q->codewords[j] >= middle_value)
600
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
601
                else
602
                    q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
603
            }else{
604
                quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
605
                if (q->codewords[j] >= middle_value)
606
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
607
                else
608
                    q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
609
            }
610
        }
611
    }
612
    return 0;
613
}
614

    
615

    
616
static int imc_get_coeffs (IMCContext* q) {
617
    int i, j, cw_len, cw;
618

    
619
    for(i = 0; i < BANDS; i++) {
620
        if(!q->sumLenArr[i]) continue;
621
        if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
622
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
623
                cw_len = q->CWlengthT[j];
624
                cw = 0;
625

    
626
                if (get_bits_count(&q->gb) + cw_len > 512){
627
//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
628
                    return -1;
629
                }
630

    
631
                if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
632
                    cw = get_bits(&q->gb, cw_len);
633

    
634
                q->codewords[j] = cw;
635
            }
636
        }
637
    }
638
    return 0;
639
}
640

    
641
static int imc_decode_frame(AVCodecContext * avctx,
642
                            void *data, int *data_size,
643
                            AVPacket *avpkt)
644
{
645
    const uint8_t *buf = avpkt->data;
646
    int buf_size = avpkt->size;
647

    
648
    IMCContext *q = avctx->priv_data;
649

    
650
    int stream_format_code;
651
    int imc_hdr, i, j;
652
    int flag;
653
    int bits, summer;
654
    int counter, bitscount;
655
    uint16_t buf16[IMC_BLOCK_SIZE / 2];
656

    
657
    if (buf_size < IMC_BLOCK_SIZE) {
658
        av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
659
        return -1;
660
    }
661
    for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
662
        buf16[i] = bswap_16(((const uint16_t*)buf)[i]);
663

    
664
    init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
665

    
666
    /* Check the frame header */
667
    imc_hdr = get_bits(&q->gb, 9);
668
    if (imc_hdr != IMC_FRAME_ID) {
669
        av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
670
        av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
671
        return -1;
672
    }
673
    stream_format_code = get_bits(&q->gb, 3);
674

    
675
    if(stream_format_code & 1){
676
        av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
677
        return -1;
678
    }
679

    
680
//    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
681

    
682
    if (stream_format_code & 0x04)
683
        q->decoder_reset = 1;
684

    
685
    if(q->decoder_reset) {
686
        memset(q->out_samples, 0, sizeof(q->out_samples));
687
        for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
688
        for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
689
        q->decoder_reset = 0;
690
    }
691

    
692
    flag = get_bits1(&q->gb);
693
    imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
694

    
695
    if (stream_format_code & 0x4)
696
        imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
697
    else
698
        imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);
699

    
700
    memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
701

    
702
    counter = 0;
703
    for (i=0 ; i<BANDS ; i++) {
704
        if (q->levlCoeffBuf[i] == 16) {
705
            q->bandWidthT[i] = 0;
706
            counter++;
707
        } else
708
            q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
709
    }
710
    memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
711
    for(i = 0; i < BANDS-1; i++) {
712
        if (q->bandWidthT[i])
713
            q->bandFlagsBuf[i] = get_bits1(&q->gb);
714
    }
715

    
716
    imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);
717

    
718
    bitscount = 0;
719
    /* first 4 bands will be assigned 5 bits per coefficient */
720
    if (stream_format_code & 0x2) {
721
        bitscount += 15;
722

    
723
        q->bitsBandT[0] = 5;
724
        q->CWlengthT[0] = 5;
725
        q->CWlengthT[1] = 5;
726
        q->CWlengthT[2] = 5;
727
        for(i = 1; i < 4; i++){
728
            bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
729
            q->bitsBandT[i] = bits;
730
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
731
                q->CWlengthT[j] = bits;
732
                bitscount += bits;
733
            }
734
        }
735
    }
736

    
737
    if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
738
        av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
739
        q->decoder_reset = 1;
740
        return -1;
741
    }
742

    
743
    for(i = 0; i < BANDS; i++) {
744
        q->sumLenArr[i] = 0;
745
        q->skipFlagRaw[i] = 0;
746
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
747
            q->sumLenArr[i] += q->CWlengthT[j];
748
        if (q->bandFlagsBuf[i])
749
            if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
750
                q->skipFlagRaw[i] = 1;
751
    }
752

    
753
    imc_get_skip_coeff(q);
754

    
755
    for(i = 0; i < BANDS; i++) {
756
        q->flcoeffs6[i] = q->flcoeffs1[i];
757
        /* band has flag set and at least one coded coefficient */
758
        if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
759
                q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
760
                                   q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
761
        }
762
    }
763

    
764
    /* calculate bits left, bits needed and adjust bit allocation */
765
    bits = summer = 0;
766

    
767
    for(i = 0; i < BANDS; i++) {
768
        if (q->bandFlagsBuf[i]) {
769
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
770
                if(q->skipFlags[j]) {
771
                    summer += q->CWlengthT[j];
772
                    q->CWlengthT[j] = 0;
773
                }
774
            }
775
            bits += q->skipFlagBits[i];
776
            summer -= q->skipFlagBits[i];
777
        }
778
    }
779
    imc_adjust_bit_allocation(q, summer);
780

    
781
    for(i = 0; i < BANDS; i++) {
782
        q->sumLenArr[i] = 0;
783

    
784
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
785
            if (!q->skipFlags[j])
786
                q->sumLenArr[i] += q->CWlengthT[j];
787
    }
788

    
789
    memset(q->codewords, 0, sizeof(q->codewords));
790

    
791
    if(imc_get_coeffs(q) < 0) {
792
        av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
793
        q->decoder_reset = 1;
794
        return 0;
795
    }
796

    
797
    if(inverse_quant_coeff(q, stream_format_code) < 0) {
798
        av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
799
        q->decoder_reset = 1;
800
        return 0;
801
    }
802

    
803
    memset(q->skipFlags, 0, sizeof(q->skipFlags));
804

    
805
    imc_imdct256(q);
806

    
807
    q->dsp.float_to_int16(data, q->out_samples, COEFFS);
808

    
809
    *data_size = COEFFS * sizeof(int16_t);
810

    
811
    return IMC_BLOCK_SIZE;
812
}
813

    
814

    
815
static av_cold int imc_decode_close(AVCodecContext * avctx)
816
{
817
    IMCContext *q = avctx->priv_data;
818

    
819
    ff_fft_end(&q->fft);
820
    return 0;
821
}
822

    
823

    
824
AVCodec imc_decoder = {
825
    .name = "imc",
826
    .type = AVMEDIA_TYPE_AUDIO,
827
    .id = CODEC_ID_IMC,
828
    .priv_data_size = sizeof(IMCContext),
829
    .init = imc_decode_init,
830
    .close = imc_decode_close,
831
    .decode = imc_decode_frame,
832
    .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
833
};