a90a07fa7deff206fa91344428e8a4a4ac27cf37
[libav.git] / libavcodec / apedec.c
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
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 };