Statistics
| Branch: | Revision:

ffmpeg / libavcodec / apedec.c @ 72415b2a

History | View | Annotate | Download (27 KB)

1
/*
2
 * Monkey's Audio lossless audio decoder
3
 * Copyright (c) 2007 Benjamin Zores <ben@geexbox.org>
4
 *  based upon libdemac from Dave Chapman.
5
 *
6
 * This file is part of FFmpeg.
7
 *
8
 * FFmpeg is free software; you can redistribute it and/or
9
 * modify it under the terms of the GNU Lesser General Public
10
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * FFmpeg is distributed in the hope that it will be useful,
14
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16
 * Lesser General Public License for more details.
17
 *
18
 * You should have received a copy of the GNU Lesser General Public
19
 * License along with FFmpeg; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22

    
23
#define ALT_BITSTREAM_READER_LE
24
#include "avcodec.h"
25
#include "dsputil.h"
26
#include "get_bits.h"
27
#include "bytestream.h"
28

    
29
/**
30
 * @file libavcodec/apedec.c
31
 * Monkey's Audio lossless audio decoder
32
 */
33

    
34
#define BLOCKS_PER_LOOP     4608
35
#define MAX_CHANNELS        2
36
#define MAX_BYTESPERSAMPLE  3
37

    
38
#define APE_FRAMECODE_MONO_SILENCE    1
39
#define APE_FRAMECODE_STEREO_SILENCE  3
40
#define APE_FRAMECODE_PSEUDO_STEREO   4
41

    
42
#define HISTORY_SIZE 512
43
#define PREDICTOR_ORDER 8
44
/** Total size of all predictor histories */
45
#define PREDICTOR_SIZE 50
46

    
47
#define YDELAYA (18 + PREDICTOR_ORDER*4)
48
#define YDELAYB (18 + PREDICTOR_ORDER*3)
49
#define XDELAYA (18 + PREDICTOR_ORDER*2)
50
#define XDELAYB (18 + PREDICTOR_ORDER)
51

    
52
#define YADAPTCOEFFSA 18
53
#define XADAPTCOEFFSA 14
54
#define YADAPTCOEFFSB 10
55
#define XADAPTCOEFFSB 5
56

    
57
/**
58
 * Possible compression levels
59
 * @{
60
 */
61
enum APECompressionLevel {
62
    COMPRESSION_LEVEL_FAST       = 1000,
63
    COMPRESSION_LEVEL_NORMAL     = 2000,
64
    COMPRESSION_LEVEL_HIGH       = 3000,
65
    COMPRESSION_LEVEL_EXTRA_HIGH = 4000,
66
    COMPRESSION_LEVEL_INSANE     = 5000
67
};
68
/** @} */
69

    
70
#define APE_FILTER_LEVELS 3
71

    
72
/** Filter orders depending on compression level */
73
static const uint16_t ape_filter_orders[5][APE_FILTER_LEVELS] = {
74
    {  0,   0,    0 },
75
    { 16,   0,    0 },
76
    { 64,   0,    0 },
77
    { 32, 256,    0 },
78
    { 16, 256, 1280 }
79
};
80

    
81
/** Filter fraction bits depending on compression level */
82
static const uint8_t ape_filter_fracbits[5][APE_FILTER_LEVELS] = {
83
    {  0,  0,  0 },
84
    { 11,  0,  0 },
85
    { 11,  0,  0 },
86
    { 10, 13,  0 },
87
    { 11, 13, 15 }
88
};
89

    
90

    
91
/** Filters applied to the decoded data */
92
typedef struct APEFilter {
93
    int16_t *coeffs;        ///< actual coefficients used in filtering
94
    int16_t *adaptcoeffs;   ///< adaptive filter coefficients used for correcting of actual filter coefficients
95
    int16_t *historybuffer; ///< filter memory
96
    int16_t *delay;         ///< filtered values
97

    
98
    int avg;
99
} APEFilter;
100

    
101
typedef struct APERice {
102
    uint32_t k;
103
    uint32_t ksum;
104
} APERice;
105

    
106
typedef struct APERangecoder {
107
    uint32_t low;           ///< low end of interval
108
    uint32_t range;         ///< length of interval
109
    uint32_t help;          ///< bytes_to_follow resp. intermediate value
110
    unsigned int buffer;    ///< buffer for input/output
111
} APERangecoder;
112

    
113
/** Filter histories */
114
typedef struct APEPredictor {
115
    int32_t *buf;
116

    
117
    int32_t lastA[2];
118

    
119
    int32_t filterA[2];
120
    int32_t filterB[2];
121

    
122
    int32_t coeffsA[2][4];  ///< adaption coefficients
123
    int32_t coeffsB[2][5];  ///< adaption coefficients
124
    int32_t historybuffer[HISTORY_SIZE + PREDICTOR_SIZE];
125
} APEPredictor;
126

    
127
/** Decoder context */
128
typedef struct APEContext {
129
    AVCodecContext *avctx;
130
    DSPContext dsp;
131
    int channels;
132
    int samples;                             ///< samples left to decode in current frame
133

    
134
    int fileversion;                         ///< codec version, very important in decoding process
135
    int compression_level;                   ///< compression levels
136
    int fset;                                ///< which filter set to use (calculated from compression level)
137
    int flags;                               ///< global decoder flags
138

    
139
    uint32_t CRC;                            ///< frame CRC
140
    int frameflags;                          ///< frame flags
141
    int currentframeblocks;                  ///< samples (per channel) in current frame
142
    int blocksdecoded;                       ///< count of decoded samples in current frame
143
    APEPredictor predictor;                  ///< predictor used for final reconstruction
144

    
145
    int32_t decoded0[BLOCKS_PER_LOOP];       ///< decoded data for the first channel
146
    int32_t decoded1[BLOCKS_PER_LOOP];       ///< decoded data for the second channel
147

    
148
    int16_t* filterbuf[APE_FILTER_LEVELS];   ///< filter memory
149

    
150
    APERangecoder rc;                        ///< rangecoder used to decode actual values
151
    APERice riceX;                           ///< rice code parameters for the second channel
152
    APERice riceY;                           ///< rice code parameters for the first channel
153
    APEFilter filters[APE_FILTER_LEVELS][2]; ///< filters used for reconstruction
154

    
155
    uint8_t *data;                           ///< current frame data
156
    uint8_t *data_end;                       ///< frame data end
157
    const uint8_t *ptr;                      ///< current position in frame data
158
    const uint8_t *last_ptr;                 ///< position where last 4608-sample block ended
159

    
160
    int error;
161
} APEContext;
162

    
163
// TODO: dsputilize
164

    
165
static av_cold int ape_decode_init(AVCodecContext * avctx)
166
{
167
    APEContext *s = avctx->priv_data;
168
    int i;
169

    
170
    if (avctx->extradata_size != 6) {
171
        av_log(avctx, AV_LOG_ERROR, "Incorrect extradata\n");
172
        return -1;
173
    }
174
    if (avctx->bits_per_coded_sample != 16) {
175
        av_log(avctx, AV_LOG_ERROR, "Only 16-bit samples are supported\n");
176
        return -1;
177
    }
178
    if (avctx->channels > 2) {
179
        av_log(avctx, AV_LOG_ERROR, "Only mono and stereo is supported\n");
180
        return -1;
181
    }
182
    s->avctx             = avctx;
183
    s->channels          = avctx->channels;
184
    s->fileversion       = AV_RL16(avctx->extradata);
185
    s->compression_level = AV_RL16(avctx->extradata + 2);
186
    s->flags             = AV_RL16(avctx->extradata + 4);
187

    
188
    av_log(avctx, AV_LOG_DEBUG, "Compression Level: %d - Flags: %d\n", s->compression_level, s->flags);
189
    if (s->compression_level % 1000 || s->compression_level > COMPRESSION_LEVEL_INSANE) {
190
        av_log(avctx, AV_LOG_ERROR, "Incorrect compression level %d\n", s->compression_level);
191
        return -1;
192
    }
193
    s->fset = s->compression_level / 1000 - 1;
194
    for (i = 0; i < APE_FILTER_LEVELS; i++) {
195
        if (!ape_filter_orders[s->fset][i])
196
            break;
197
        s->filterbuf[i] = av_malloc((ape_filter_orders[s->fset][i] * 3 + HISTORY_SIZE) * 4);
198
    }
199

    
200
    dsputil_init(&s->dsp, avctx);
201
    avctx->sample_fmt = SAMPLE_FMT_S16;
202
    avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;
203
    return 0;
204
}
205

    
206
static av_cold int ape_decode_close(AVCodecContext * avctx)
207
{
208
    APEContext *s = avctx->priv_data;
209
    int i;
210

    
211
    for (i = 0; i < APE_FILTER_LEVELS; i++)
212
        av_freep(&s->filterbuf[i]);
213

    
214
    av_freep(&s->data);
215
    return 0;
216
}
217

    
218
/**
219
 * @defgroup rangecoder APE range decoder
220
 * @{
221
 */
222

    
223
#define CODE_BITS    32
224
#define TOP_VALUE    ((unsigned int)1 << (CODE_BITS-1))
225
#define SHIFT_BITS   (CODE_BITS - 9)
226
#define EXTRA_BITS   ((CODE_BITS-2) % 8 + 1)
227
#define BOTTOM_VALUE (TOP_VALUE >> 8)
228

    
229
/** Start the decoder */
230
static inline void range_start_decoding(APEContext * ctx)
231
{
232
    ctx->rc.buffer = bytestream_get_byte(&ctx->ptr);
233
    ctx->rc.low    = ctx->rc.buffer >> (8 - EXTRA_BITS);
234
    ctx->rc.range  = (uint32_t) 1 << EXTRA_BITS;
235
}
236

    
237
/** Perform normalization */
238
static inline void range_dec_normalize(APEContext * ctx)
239
{
240
    while (ctx->rc.range <= BOTTOM_VALUE) {
241
        ctx->rc.buffer <<= 8;
242
        if(ctx->ptr < ctx->data_end)
243
            ctx->rc.buffer += *ctx->ptr;
244
        ctx->ptr++;
245
        ctx->rc.low    = (ctx->rc.low << 8)    | ((ctx->rc.buffer >> 1) & 0xFF);
246
        ctx->rc.range  <<= 8;
247
    }
248
}
249

    
250
/**
251
 * Calculate culmulative frequency for next symbol. Does NO update!
252
 * @param ctx decoder context
253
 * @param tot_f is the total frequency or (code_value)1<<shift
254
 * @return the culmulative frequency
255
 */
256
static inline int range_decode_culfreq(APEContext * ctx, int tot_f)
257
{
258
    range_dec_normalize(ctx);
259
    ctx->rc.help = ctx->rc.range / tot_f;
260
    return ctx->rc.low / ctx->rc.help;
261
}
262

    
263
/**
264
 * Decode value with given size in bits
265
 * @param ctx decoder context
266
 * @param shift number of bits to decode
267
 */
268
static inline int range_decode_culshift(APEContext * ctx, int shift)
269
{
270
    range_dec_normalize(ctx);
271
    ctx->rc.help = ctx->rc.range >> shift;
272
    return ctx->rc.low / ctx->rc.help;
273
}
274

    
275

    
276
/**
277
 * Update decoding state
278
 * @param ctx decoder context
279
 * @param sy_f the interval length (frequency of the symbol)
280
 * @param lt_f the lower end (frequency sum of < symbols)
281
 */
282
static inline void range_decode_update(APEContext * ctx, int sy_f, int lt_f)
283
{
284
    ctx->rc.low  -= ctx->rc.help * lt_f;
285
    ctx->rc.range = ctx->rc.help * sy_f;
286
}
287

    
288
/** Decode n bits (n <= 16) without modelling */
289
static inline int range_decode_bits(APEContext * ctx, int n)
290
{
291
    int sym = range_decode_culshift(ctx, n);
292
    range_decode_update(ctx, 1, sym);
293
    return sym;
294
}
295

    
296

    
297
#define MODEL_ELEMENTS 64
298

    
299
/**
300
 * Fixed probabilities for symbols in Monkey Audio version 3.97
301
 */
302
static const uint16_t counts_3970[22] = {
303
        0, 14824, 28224, 39348, 47855, 53994, 58171, 60926,
304
    62682, 63786, 64463, 64878, 65126, 65276, 65365, 65419,
305
    65450, 65469, 65480, 65487, 65491, 65493,
306
};
307

    
308
/**
309
 * Probability ranges for symbols in Monkey Audio version 3.97
310
 */
311
static const uint16_t counts_diff_3970[21] = {
312
    14824, 13400, 11124, 8507, 6139, 4177, 2755, 1756,
313
    1104, 677, 415, 248, 150, 89, 54, 31,
314
    19, 11, 7, 4, 2,
315
};
316

    
317
/**
318
 * Fixed probabilities for symbols in Monkey Audio version 3.98
319
 */
320
static const uint16_t counts_3980[22] = {
321
        0, 19578, 36160, 48417, 56323, 60899, 63265, 64435,
322
    64971, 65232, 65351, 65416, 65447, 65466, 65476, 65482,
323
    65485, 65488, 65490, 65491, 65492, 65493,
324
};
325

    
326
/**
327
 * Probability ranges for symbols in Monkey Audio version 3.98
328
 */
329
static const uint16_t counts_diff_3980[21] = {
330
    19578, 16582, 12257, 7906, 4576, 2366, 1170, 536,
331
    261, 119, 65, 31, 19, 10, 6, 3,
332
    3, 2, 1, 1, 1,
333
};
334

    
335
/**
336
 * Decode symbol
337
 * @param ctx decoder context
338
 * @param counts probability range start position
339
 * @param counts_diff probability range widths
340
 */
341
static inline int range_get_symbol(APEContext * ctx,
342
                                   const uint16_t counts[],
343
                                   const uint16_t counts_diff[])
344
{
345
    int symbol, cf;
346

    
347
    cf = range_decode_culshift(ctx, 16);
348

    
349
    if(cf > 65492){
350
        symbol= cf - 65535 + 63;
351
        range_decode_update(ctx, 1, cf);
352
        if(cf > 65535)
353
            ctx->error=1;
354
        return symbol;
355
    }
356
    /* figure out the symbol inefficiently; a binary search would be much better */
357
    for (symbol = 0; counts[symbol + 1] <= cf; symbol++);
358

    
359
    range_decode_update(ctx, counts_diff[symbol], counts[symbol]);
360

    
361
    return symbol;
362
}
363
/** @} */ // group rangecoder
364

    
365
static inline void update_rice(APERice *rice, int x)
366
{
367
    int lim = rice->k ? (1 << (rice->k + 4)) : 0;
368
    rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5);
369

    
370
    if (rice->ksum < lim)
371
        rice->k--;
372
    else if (rice->ksum >= (1 << (rice->k + 5)))
373
        rice->k++;
374
}
375

    
376
static inline int ape_decode_value(APEContext * ctx, APERice *rice)
377
{
378
    int x, overflow;
379

    
380
    if (ctx->fileversion < 3990) {
381
        int tmpk;
382

    
383
        overflow = range_get_symbol(ctx, counts_3970, counts_diff_3970);
384

    
385
        if (overflow == (MODEL_ELEMENTS - 1)) {
386
            tmpk = range_decode_bits(ctx, 5);
387
            overflow = 0;
388
        } else
389
            tmpk = (rice->k < 1) ? 0 : rice->k - 1;
390

    
391
        if (tmpk <= 16)
392
            x = range_decode_bits(ctx, tmpk);
393
        else {
394
            x = range_decode_bits(ctx, 16);
395
            x |= (range_decode_bits(ctx, tmpk - 16) << 16);
396
        }
397
        x += overflow << tmpk;
398
    } else {
399
        int base, pivot;
400

    
401
        pivot = rice->ksum >> 5;
402
        if (pivot == 0)
403
            pivot = 1;
404

    
405
        overflow = range_get_symbol(ctx, counts_3980, counts_diff_3980);
406

    
407
        if (overflow == (MODEL_ELEMENTS - 1)) {
408
            overflow  = range_decode_bits(ctx, 16) << 16;
409
            overflow |= range_decode_bits(ctx, 16);
410
        }
411

    
412
        if (pivot < 0x10000) {
413
            base = range_decode_culfreq(ctx, pivot);
414
            range_decode_update(ctx, 1, base);
415
        } else {
416
            int base_hi = pivot, base_lo;
417
            int bbits = 0;
418

    
419
            while (base_hi & ~0xFFFF) {
420
                base_hi >>= 1;
421
                bbits++;
422
            }
423
            base_hi = range_decode_culfreq(ctx, base_hi + 1);
424
            range_decode_update(ctx, 1, base_hi);
425
            base_lo = range_decode_culfreq(ctx, 1 << bbits);
426
            range_decode_update(ctx, 1, base_lo);
427

    
428
            base = (base_hi << bbits) + base_lo;
429
        }
430

    
431
        x = base + overflow * pivot;
432
    }
433

    
434
    update_rice(rice, x);
435

    
436
    /* Convert to signed */
437
    if (x & 1)
438
        return (x >> 1) + 1;
439
    else
440
        return -(x >> 1);
441
}
442

    
443
static void entropy_decode(APEContext * ctx, int blockstodecode, int stereo)
444
{
445
    int32_t *decoded0 = ctx->decoded0;
446
    int32_t *decoded1 = ctx->decoded1;
447

    
448
    ctx->blocksdecoded = blockstodecode;
449

    
450
    if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
451
        /* We are pure silence, just memset the output buffer. */
452
        memset(decoded0, 0, blockstodecode * sizeof(int32_t));
453
        memset(decoded1, 0, blockstodecode * sizeof(int32_t));
454
    } else {
455
        while (blockstodecode--) {
456
            *decoded0++ = ape_decode_value(ctx, &ctx->riceY);
457
            if (stereo)
458
                *decoded1++ = ape_decode_value(ctx, &ctx->riceX);
459
        }
460
    }
461

    
462
    if (ctx->blocksdecoded == ctx->currentframeblocks)
463
        range_dec_normalize(ctx);   /* normalize to use up all bytes */
464
}
465

    
466
static void init_entropy_decoder(APEContext * ctx)
467
{
468
    /* Read the CRC */
469
    ctx->CRC = bytestream_get_be32(&ctx->ptr);
470

    
471
    /* Read the frame flags if they exist */
472
    ctx->frameflags = 0;
473
    if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) {
474
        ctx->CRC &= ~0x80000000;
475

    
476
        ctx->frameflags = bytestream_get_be32(&ctx->ptr);
477
    }
478

    
479
    /* Keep a count of the blocks decoded in this frame */
480
    ctx->blocksdecoded = 0;
481

    
482
    /* Initialize the rice structs */
483
    ctx->riceX.k = 10;
484
    ctx->riceX.ksum = (1 << ctx->riceX.k) * 16;
485
    ctx->riceY.k = 10;
486
    ctx->riceY.ksum = (1 << ctx->riceY.k) * 16;
487

    
488
    /* The first 8 bits of input are ignored. */
489
    ctx->ptr++;
490

    
491
    range_start_decoding(ctx);
492
}
493

    
494
static const int32_t initial_coeffs[4] = {
495
    360, 317, -109, 98
496
};
497

    
498
static void init_predictor_decoder(APEContext * ctx)
499
{
500
    APEPredictor *p = &ctx->predictor;
501

    
502
    /* Zero the history buffers */
503
    memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t));
504
    p->buf = p->historybuffer;
505

    
506
    /* Initialize and zero the coefficients */
507
    memcpy(p->coeffsA[0], initial_coeffs, sizeof(initial_coeffs));
508
    memcpy(p->coeffsA[1], initial_coeffs, sizeof(initial_coeffs));
509
    memset(p->coeffsB, 0, sizeof(p->coeffsB));
510

    
511
    p->filterA[0] = p->filterA[1] = 0;
512
    p->filterB[0] = p->filterB[1] = 0;
513
    p->lastA[0]   = p->lastA[1]   = 0;
514
}
515

    
516
/** Get inverse sign of integer (-1 for positive, 1 for negative and 0 for zero) */
517
static inline int APESIGN(int32_t x) {
518
    return (x < 0) - (x > 0);
519
}
520

    
521
static av_always_inline int predictor_update_filter(APEPredictor *p, const int decoded, const int filter, const int delayA, const int delayB, const int adaptA, const int adaptB)
522
{
523
    int32_t predictionA, predictionB, sign;
524

    
525
    p->buf[delayA]     = p->lastA[filter];
526
    p->buf[adaptA]     = APESIGN(p->buf[delayA]);
527
    p->buf[delayA - 1] = p->buf[delayA] - p->buf[delayA - 1];
528
    p->buf[adaptA - 1] = APESIGN(p->buf[delayA - 1]);
529

    
530
    predictionA = p->buf[delayA    ] * p->coeffsA[filter][0] +
531
                  p->buf[delayA - 1] * p->coeffsA[filter][1] +
532
                  p->buf[delayA - 2] * p->coeffsA[filter][2] +
533
                  p->buf[delayA - 3] * p->coeffsA[filter][3];
534

    
535
    /*  Apply a scaled first-order filter compression */
536
    p->buf[delayB]     = p->filterA[filter ^ 1] - ((p->filterB[filter] * 31) >> 5);
537
    p->buf[adaptB]     = APESIGN(p->buf[delayB]);
538
    p->buf[delayB - 1] = p->buf[delayB] - p->buf[delayB - 1];
539
    p->buf[adaptB - 1] = APESIGN(p->buf[delayB - 1]);
540
    p->filterB[filter] = p->filterA[filter ^ 1];
541

    
542
    predictionB = p->buf[delayB    ] * p->coeffsB[filter][0] +
543
                  p->buf[delayB - 1] * p->coeffsB[filter][1] +
544
                  p->buf[delayB - 2] * p->coeffsB[filter][2] +
545
                  p->buf[delayB - 3] * p->coeffsB[filter][3] +
546
                  p->buf[delayB - 4] * p->coeffsB[filter][4];
547

    
548
    p->lastA[filter] = decoded + ((predictionA + (predictionB >> 1)) >> 10);
549
    p->filterA[filter] = p->lastA[filter] + ((p->filterA[filter] * 31) >> 5);
550

    
551
    sign = APESIGN(decoded);
552
    p->coeffsA[filter][0] += p->buf[adaptA    ] * sign;
553
    p->coeffsA[filter][1] += p->buf[adaptA - 1] * sign;
554
    p->coeffsA[filter][2] += p->buf[adaptA - 2] * sign;
555
    p->coeffsA[filter][3] += p->buf[adaptA - 3] * sign;
556
    p->coeffsB[filter][0] += p->buf[adaptB    ] * sign;
557
    p->coeffsB[filter][1] += p->buf[adaptB - 1] * sign;
558
    p->coeffsB[filter][2] += p->buf[adaptB - 2] * sign;
559
    p->coeffsB[filter][3] += p->buf[adaptB - 3] * sign;
560
    p->coeffsB[filter][4] += p->buf[adaptB - 4] * sign;
561

    
562
    return p->filterA[filter];
563
}
564

    
565
static void predictor_decode_stereo(APEContext * ctx, int count)
566
{
567
    APEPredictor *p = &ctx->predictor;
568
    int32_t *decoded0 = ctx->decoded0;
569
    int32_t *decoded1 = ctx->decoded1;
570

    
571
    while (count--) {
572
        /* Predictor Y */
573
        *decoded0 = predictor_update_filter(p, *decoded0, 0, YDELAYA, YDELAYB, YADAPTCOEFFSA, YADAPTCOEFFSB);
574
        decoded0++;
575
        *decoded1 = predictor_update_filter(p, *decoded1, 1, XDELAYA, XDELAYB, XADAPTCOEFFSA, XADAPTCOEFFSB);
576
        decoded1++;
577

    
578
        /* Combined */
579
        p->buf++;
580

    
581
        /* Have we filled the history buffer? */
582
        if (p->buf == p->historybuffer + HISTORY_SIZE) {
583
            memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t));
584
            p->buf = p->historybuffer;
585
        }
586
    }
587
}
588

    
589
static void predictor_decode_mono(APEContext * ctx, int count)
590
{
591
    APEPredictor *p = &ctx->predictor;
592
    int32_t *decoded0 = ctx->decoded0;
593
    int32_t predictionA, currentA, A, sign;
594

    
595
    currentA = p->lastA[0];
596

    
597
    while (count--) {
598
        A = *decoded0;
599

    
600
        p->buf[YDELAYA] = currentA;
601
        p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1];
602

    
603
        predictionA = p->buf[YDELAYA    ] * p->coeffsA[0][0] +
604
                      p->buf[YDELAYA - 1] * p->coeffsA[0][1] +
605
                      p->buf[YDELAYA - 2] * p->coeffsA[0][2] +
606
                      p->buf[YDELAYA - 3] * p->coeffsA[0][3];
607

    
608
        currentA = A + (predictionA >> 10);
609

    
610
        p->buf[YADAPTCOEFFSA]     = APESIGN(p->buf[YDELAYA    ]);
611
        p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]);
612

    
613
        sign = APESIGN(A);
614
        p->coeffsA[0][0] += p->buf[YADAPTCOEFFSA    ] * sign;
615
        p->coeffsA[0][1] += p->buf[YADAPTCOEFFSA - 1] * sign;
616
        p->coeffsA[0][2] += p->buf[YADAPTCOEFFSA - 2] * sign;
617
        p->coeffsA[0][3] += p->buf[YADAPTCOEFFSA - 3] * sign;
618

    
619
        p->buf++;
620

    
621
        /* Have we filled the history buffer? */
622
        if (p->buf == p->historybuffer + HISTORY_SIZE) {
623
            memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t));
624
            p->buf = p->historybuffer;
625
        }
626

    
627
        p->filterA[0] = currentA + ((p->filterA[0] * 31) >> 5);
628
        *(decoded0++) = p->filterA[0];
629
    }
630

    
631
    p->lastA[0] = currentA;
632
}
633

    
634
static void do_init_filter(APEFilter *f, int16_t * buf, int order)
635
{
636
    f->coeffs = buf;
637
    f->historybuffer = buf + order;
638
    f->delay       = f->historybuffer + order * 2;
639
    f->adaptcoeffs = f->historybuffer + order;
640

    
641
    memset(f->historybuffer, 0, (order * 2) * sizeof(int16_t));
642
    memset(f->coeffs, 0, order * sizeof(int16_t));
643
    f->avg = 0;
644
}
645

    
646
static void init_filter(APEContext * ctx, APEFilter *f, int16_t * buf, int order)
647
{
648
    do_init_filter(&f[0], buf, order);
649
    do_init_filter(&f[1], buf + order * 3 + HISTORY_SIZE, order);
650
}
651

    
652
static void do_apply_filter(APEContext * ctx, int version, APEFilter *f, int32_t *data, int count, int order, int fracbits)
653
{
654
    int res;
655
    int absres;
656

    
657
    while (count--) {
658
        /* round fixedpoint scalar product */
659
        res = ctx->dsp.scalarproduct_and_madd_int16(f->coeffs, f->delay - order, f->adaptcoeffs - order, order, APESIGN(*data));
660
        res = (res + (1 << (fracbits - 1))) >> fracbits;
661
        res += *data;
662
        *data++ = res;
663

    
664
        /* Update the output history */
665
        *f->delay++ = av_clip_int16(res);
666

    
667
        if (version < 3980) {
668
            /* Version ??? to < 3.98 files (untested) */
669
            f->adaptcoeffs[0]  = (res == 0) ? 0 : ((res >> 28) & 8) - 4;
670
            f->adaptcoeffs[-4] >>= 1;
671
            f->adaptcoeffs[-8] >>= 1;
672
        } else {
673
            /* Version 3.98 and later files */
674

    
675
            /* Update the adaption coefficients */
676
            absres = FFABS(res);
677
            if (absres)
678
                *f->adaptcoeffs = ((res & (1<<31)) - (1<<30)) >> (25 + (absres <= f->avg*3) + (absres <= f->avg*4/3));
679
            else
680
                *f->adaptcoeffs = 0;
681

    
682
            f->avg += (absres - f->avg) / 16;
683

    
684
            f->adaptcoeffs[-1] >>= 1;
685
            f->adaptcoeffs[-2] >>= 1;
686
            f->adaptcoeffs[-8] >>= 1;
687
        }
688

    
689
        f->adaptcoeffs++;
690

    
691
        /* Have we filled the history buffer? */
692
        if (f->delay == f->historybuffer + HISTORY_SIZE + (order * 2)) {
693
            memmove(f->historybuffer, f->delay - (order * 2),
694
                    (order * 2) * sizeof(int16_t));
695
            f->delay = f->historybuffer + order * 2;
696
            f->adaptcoeffs = f->historybuffer + order;
697
        }
698
    }
699
}
700

    
701
static void apply_filter(APEContext * ctx, APEFilter *f,
702
                         int32_t * data0, int32_t * data1,
703
                         int count, int order, int fracbits)
704
{
705
    do_apply_filter(ctx, ctx->fileversion, &f[0], data0, count, order, fracbits);
706
    if (data1)
707
        do_apply_filter(ctx, ctx->fileversion, &f[1], data1, count, order, fracbits);
708
}
709

    
710
static void ape_apply_filters(APEContext * ctx, int32_t * decoded0,
711
                              int32_t * decoded1, int count)
712
{
713
    int i;
714

    
715
    for (i = 0; i < APE_FILTER_LEVELS; i++) {
716
        if (!ape_filter_orders[ctx->fset][i])
717
            break;
718
        apply_filter(ctx, ctx->filters[i], decoded0, decoded1, count, ape_filter_orders[ctx->fset][i], ape_filter_fracbits[ctx->fset][i]);
719
    }
720
}
721

    
722
static void init_frame_decoder(APEContext * ctx)
723
{
724
    int i;
725
    init_entropy_decoder(ctx);
726
    init_predictor_decoder(ctx);
727

    
728
    for (i = 0; i < APE_FILTER_LEVELS; i++) {
729
        if (!ape_filter_orders[ctx->fset][i])
730
            break;
731
        init_filter(ctx, ctx->filters[i], ctx->filterbuf[i], ape_filter_orders[ctx->fset][i]);
732
    }
733
}
734

    
735
static void ape_unpack_mono(APEContext * ctx, int count)
736
{
737
    int32_t left;
738
    int32_t *decoded0 = ctx->decoded0;
739
    int32_t *decoded1 = ctx->decoded1;
740

    
741
    if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
742
        entropy_decode(ctx, count, 0);
743
        /* We are pure silence, so we're done. */
744
        av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence mono\n");
745
        return;
746
    }
747

    
748
    entropy_decode(ctx, count, 0);
749
    ape_apply_filters(ctx, decoded0, NULL, count);
750

    
751
    /* Now apply the predictor decoding */
752
    predictor_decode_mono(ctx, count);
753

    
754
    /* Pseudo-stereo - just copy left channel to right channel */
755
    if (ctx->channels == 2) {
756
        while (count--) {
757
            left = *decoded0;
758
            *(decoded1++) = *(decoded0++) = left;
759
        }
760
    }
761
}
762

    
763
static void ape_unpack_stereo(APEContext * ctx, int count)
764
{
765
    int32_t left, right;
766
    int32_t *decoded0 = ctx->decoded0;
767
    int32_t *decoded1 = ctx->decoded1;
768

    
769
    if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
770
        /* We are pure silence, so we're done. */
771
        av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence stereo\n");
772
        return;
773
    }
774

    
775
    entropy_decode(ctx, count, 1);
776
    ape_apply_filters(ctx, decoded0, decoded1, count);
777

    
778
    /* Now apply the predictor decoding */
779
    predictor_decode_stereo(ctx, count);
780

    
781
    /* Decorrelate and scale to output depth */
782
    while (count--) {
783
        left = *decoded1 - (*decoded0 / 2);
784
        right = left + *decoded0;
785

    
786
        *(decoded0++) = left;
787
        *(decoded1++) = right;
788
    }
789
}
790

    
791
static int ape_decode_frame(AVCodecContext * avctx,
792
                            void *data, int *data_size,
793
                            AVPacket *avpkt)
794
{
795
    const uint8_t *buf = avpkt->data;
796
    int buf_size = avpkt->size;
797
    APEContext *s = avctx->priv_data;
798
    int16_t *samples = data;
799
    int nblocks;
800
    int i, n;
801
    int blockstodecode;
802
    int bytes_used;
803

    
804
    if (buf_size == 0 && !s->samples) {
805
        *data_size = 0;
806
        return 0;
807
    }
808

    
809
    /* should not happen but who knows */
810
    if (BLOCKS_PER_LOOP * 2 * avctx->channels > *data_size) {
811
        av_log (avctx, AV_LOG_ERROR, "Packet size is too big to be handled in lavc! (max is %d where you have %d)\n", *data_size, s->samples * 2 * avctx->channels);
812
        return -1;
813
    }
814

    
815
    if(!s->samples){
816
        s->data = av_realloc(s->data, (buf_size + 3) & ~3);
817
        s->dsp.bswap_buf((uint32_t*)s->data, (const uint32_t*)buf, buf_size >> 2);
818
        s->ptr = s->last_ptr = s->data;
819
        s->data_end = s->data + buf_size;
820

    
821
        nblocks = s->samples = bytestream_get_be32(&s->ptr);
822
        n =  bytestream_get_be32(&s->ptr);
823
        if(n < 0 || n > 3){
824
            av_log(avctx, AV_LOG_ERROR, "Incorrect offset passed\n");
825
            s->data = NULL;
826
            return -1;
827
        }
828
        s->ptr += n;
829

    
830
        s->currentframeblocks = nblocks;
831
        buf += 4;
832
        if (s->samples <= 0) {
833
            *data_size = 0;
834
            return buf_size;
835
        }
836

    
837
        memset(s->decoded0,  0, sizeof(s->decoded0));
838
        memset(s->decoded1,  0, sizeof(s->decoded1));
839

    
840
        /* Initialize the frame decoder */
841
        init_frame_decoder(s);
842
    }
843

    
844
    if (!s->data) {
845
        *data_size = 0;
846
        return buf_size;
847
    }
848

    
849
    nblocks = s->samples;
850
    blockstodecode = FFMIN(BLOCKS_PER_LOOP, nblocks);
851

    
852
    s->error=0;
853

    
854
    if ((s->channels == 1) || (s->frameflags & APE_FRAMECODE_PSEUDO_STEREO))
855
        ape_unpack_mono(s, blockstodecode);
856
    else
857
        ape_unpack_stereo(s, blockstodecode);
858
    emms_c();
859

    
860
    if(s->error || s->ptr > s->data_end){
861
        s->samples=0;
862
        av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n");
863
        return -1;
864
    }
865

    
866
    for (i = 0; i < blockstodecode; i++) {
867
        *samples++ = s->decoded0[i];
868
        if(s->channels == 2)
869
            *samples++ = s->decoded1[i];
870
    }
871

    
872
    s->samples -= blockstodecode;
873

    
874
    *data_size = blockstodecode * 2 * s->channels;
875
    bytes_used = s->samples ? s->ptr - s->last_ptr : buf_size;
876
    s->last_ptr = s->ptr;
877
    return bytes_used;
878
}
879

    
880
AVCodec ape_decoder = {
881
    "ape",
882
    AVMEDIA_TYPE_AUDIO,
883
    CODEC_ID_APE,
884
    sizeof(APEContext),
885
    ape_decode_init,
886
    NULL,
887
    ape_decode_close,
888
    ape_decode_frame,
889
    .capabilities = CODEC_CAP_SUBFRAMES,
890
    .long_name = NULL_IF_CONFIG_SMALL("Monkey's Audio"),
891
};