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Be more verbose in describing VQF demuxer
[ffmpeg-lucabe.git] / libavcodec / apedec.c
blob59be99694e4799f3bce45625e351455d2cddfd6f
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 "bitstream.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 return 0;
215 }
216
217 /**
218 * @defgroup rangecoder APE range decoder
219 * @{
220 */
221
222 #define CODE_BITS 32
223 #define TOP_VALUE ((unsigned int)1 << (CODE_BITS-1))
224 #define SHIFT_BITS (CODE_BITS - 9)
225 #define EXTRA_BITS ((CODE_BITS-2) % 8 + 1)
226 #define BOTTOM_VALUE (TOP_VALUE >> 8)
227
228 /** Start the decoder */
229 static inline void range_start_decoding(APEContext * ctx)
230 {
231 ctx->rc.buffer = bytestream_get_byte(&ctx->ptr);
232 ctx->rc.low = ctx->rc.buffer >> (8 - EXTRA_BITS);
233 ctx->rc.range = (uint32_t) 1 << EXTRA_BITS;
234 }
235
236 /** Perform normalization */
237 static inline void range_dec_normalize(APEContext * ctx)
238 {
239 while (ctx->rc.range <= BOTTOM_VALUE) {
240 ctx->rc.buffer <<= 8;
241 if(ctx->ptr < ctx->data_end)
242 ctx->rc.buffer += *ctx->ptr;
243 ctx->ptr++;
244 ctx->rc.low = (ctx->rc.low << 8) | ((ctx->rc.buffer >> 1) & 0xFF);
245 ctx->rc.range <<= 8;
246 }
247 }
248
249 /**
250 * Calculate culmulative frequency for next symbol. Does NO update!
251 * @param ctx decoder context
252 * @param tot_f is the total frequency or (code_value)1<<shift
253 * @return the culmulative frequency
254 */
255 static inline int range_decode_culfreq(APEContext * ctx, int tot_f)
256 {
257 range_dec_normalize(ctx);
258 ctx->rc.help = ctx->rc.range / tot_f;
259 return ctx->rc.low / ctx->rc.help;
260 }
261
262 /**
263 * Decode value with given size in bits
264 * @param ctx decoder context
265 * @param shift number of bits to decode
266 */
267 static inline int range_decode_culshift(APEContext * ctx, int shift)
268 {
269 range_dec_normalize(ctx);
270 ctx->rc.help = ctx->rc.range >> shift;
271 return ctx->rc.low / ctx->rc.help;
272 }
273
274
275 /**
276 * Update decoding state
277 * @param ctx decoder context
278 * @param sy_f the interval length (frequency of the symbol)
279 * @param lt_f the lower end (frequency sum of < symbols)
280 */
281 static inline void range_decode_update(APEContext * ctx, int sy_f, int lt_f)
282 {
283 ctx->rc.low -= ctx->rc.help * lt_f;
284 ctx->rc.range = ctx->rc.help * sy_f;
285 }
286
287 /** Decode n bits (n <= 16) without modelling */
288 static inline int range_decode_bits(APEContext * ctx, int n)
289 {
290 int sym = range_decode_culshift(ctx, n);
291 range_decode_update(ctx, 1, sym);
292 return sym;
293 }
294
295
296 #define MODEL_ELEMENTS 64
297
298 /**
299 * Fixed probabilities for symbols in Monkey Audio version 3.97
300 */
301 static const uint16_t counts_3970[22] = {
302 0, 14824, 28224, 39348, 47855, 53994, 58171, 60926,
303 62682, 63786, 64463, 64878, 65126, 65276, 65365, 65419,
304 65450, 65469, 65480, 65487, 65491, 65493,
305 };
306
307 /**
308 * Probability ranges for symbols in Monkey Audio version 3.97
309 */
310 static const uint16_t counts_diff_3970[21] = {
311 14824, 13400, 11124, 8507, 6139, 4177, 2755, 1756,
312 1104, 677, 415, 248, 150, 89, 54, 31,
313 19, 11, 7, 4, 2,
314 };
315
316 /**
317 * Fixed probabilities for symbols in Monkey Audio version 3.98
318 */
319 static const uint16_t counts_3980[22] = {
320 0, 19578, 36160, 48417, 56323, 60899, 63265, 64435,
321 64971, 65232, 65351, 65416, 65447, 65466, 65476, 65482,
322 65485, 65488, 65490, 65491, 65492, 65493,
323 };
324
325 /**
326 * Probability ranges for symbols in Monkey Audio version 3.98
327 */
328 static const uint16_t counts_diff_3980[21] = {
329 19578, 16582, 12257, 7906, 4576, 2366, 1170, 536,
330 261, 119, 65, 31, 19, 10, 6, 3,
331 3, 2, 1, 1, 1,
332 };
333
334 /**
335 * Decode symbol
336 * @param ctx decoder context
337 * @param counts probability range start position
338 * @param counts_diff probability range widths
339 */
340 static inline int range_get_symbol(APEContext * ctx,
341 const uint16_t counts[],
342 const uint16_t counts_diff[])
343 {
344 int symbol, cf;
345
346 cf = range_decode_culshift(ctx, 16);
347
348 if(cf > 65492){
349 symbol= cf - 65535 + 63;
350 range_decode_update(ctx, 1, cf);
351 if(cf > 65535)
352 ctx->error=1;
353 return symbol;
354 }
355 /* figure out the symbol inefficiently; a binary search would be much better */
356 for (symbol = 0; counts[symbol + 1] <= cf; symbol++);
357
358 range_decode_update(ctx, counts_diff[symbol], counts[symbol]);
359
360 return symbol;
361 }
362 /** @} */ // group rangecoder
363
364 static inline void update_rice(APERice *rice, int x)
365 {
366 int lim = rice->k ? (1 << (rice->k + 4)) : 0;
367 rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5);
368
369 if (rice->ksum < lim)
370 rice->k--;
371 else if (rice->ksum >= (1 << (rice->k + 5)))
372 rice->k++;
373 }
374
375 static inline int ape_decode_value(APEContext * ctx, APERice *rice)
376 {
377 int x, overflow;
378
379 if (ctx->fileversion < 3990) {
380 int tmpk;
381
382 overflow = range_get_symbol(ctx, counts_3970, counts_diff_3970);
383
384 if (overflow == (MODEL_ELEMENTS - 1)) {
385 tmpk = range_decode_bits(ctx, 5);
386 overflow = 0;
387 } else
388 tmpk = (rice->k < 1) ? 0 : rice->k - 1;
389
390 if (tmpk <= 16)
391 x = range_decode_bits(ctx, tmpk);
392 else {
393 x = range_decode_bits(ctx, 16);
394 x |= (range_decode_bits(ctx, tmpk - 16) << 16);
395 }
396 x += overflow << tmpk;
397 } else {
398 int base, pivot;
399
400 pivot = rice->ksum >> 5;
401 if (pivot == 0)
402 pivot = 1;
403
404 overflow = range_get_symbol(ctx, counts_3980, counts_diff_3980);
405
406 if (overflow == (MODEL_ELEMENTS - 1)) {
407 overflow = range_decode_bits(ctx, 16) << 16;
408 overflow |= range_decode_bits(ctx, 16);
409 }
410
411 base = range_decode_culfreq(ctx, pivot);
412 range_decode_update(ctx, 1, base);
413
414 x = base + overflow * pivot;
415 }
416
417 update_rice(rice, x);
418
419 /* Convert to signed */
420 if (x & 1)
421 return (x >> 1) + 1;
422 else
423 return -(x >> 1);
424 }
425
426 static void entropy_decode(APEContext * ctx, int blockstodecode, int stereo)
427 {
428 int32_t *decoded0 = ctx->decoded0;
429 int32_t *decoded1 = ctx->decoded1;
430
431 ctx->blocksdecoded = blockstodecode;
432
433 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
434 /* We are pure silence, just memset the output buffer. */
435 memset(decoded0, 0, blockstodecode * sizeof(int32_t));
436 memset(decoded1, 0, blockstodecode * sizeof(int32_t));
437 } else {
438 while (blockstodecode--) {
439 *decoded0++ = ape_decode_value(ctx, &ctx->riceY);
440 if (stereo)
441 *decoded1++ = ape_decode_value(ctx, &ctx->riceX);
442 }
443 }
444
445 if (ctx->blocksdecoded == ctx->currentframeblocks)
446 range_dec_normalize(ctx); /* normalize to use up all bytes */
447 }
448
449 static void init_entropy_decoder(APEContext * ctx)
450 {
451 /* Read the CRC */
452 ctx->CRC = bytestream_get_be32(&ctx->ptr);
453
454 /* Read the frame flags if they exist */
455 ctx->frameflags = 0;
456 if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) {
457 ctx->CRC &= ~0x80000000;
458
459 ctx->frameflags = bytestream_get_be32(&ctx->ptr);
460 }
461
462 /* Keep a count of the blocks decoded in this frame */
463 ctx->blocksdecoded = 0;
464
465 /* Initialize the rice structs */
466 ctx->riceX.k = 10;
467 ctx->riceX.ksum = (1 << ctx->riceX.k) * 16;
468 ctx->riceY.k = 10;
469 ctx->riceY.ksum = (1 << ctx->riceY.k) * 16;
470
471 /* The first 8 bits of input are ignored. */
472 ctx->ptr++;
473
474 range_start_decoding(ctx);
475 }
476
477 static const int32_t initial_coeffs[4] = {
478 360, 317, -109, 98
479 };
480
481 static void init_predictor_decoder(APEContext * ctx)
482 {
483 APEPredictor *p = &ctx->predictor;
484
485 /* Zero the history buffers */
486 memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t));
487 p->buf = p->historybuffer;
488
489 /* Initialize and zero the coefficients */
490 memcpy(p->coeffsA[0], initial_coeffs, sizeof(initial_coeffs));
491 memcpy(p->coeffsA[1], initial_coeffs, sizeof(initial_coeffs));
492 memset(p->coeffsB, 0, sizeof(p->coeffsB));
493
494 p->filterA[0] = p->filterA[1] = 0;
495 p->filterB[0] = p->filterB[1] = 0;
496 p->lastA[0] = p->lastA[1] = 0;
497 }
498
499 /** Get inverse sign of integer (-1 for positive, 1 for negative and 0 for zero) */
500 static inline int APESIGN(int32_t x) {
501 return (x < 0) - (x > 0);
502 }
503
504 static int predictor_update_filter(APEPredictor *p, const int decoded, const int filter, const int delayA, const int delayB, const int adaptA, const int adaptB)
505 {
506 int32_t predictionA, predictionB;
507
508 p->buf[delayA] = p->lastA[filter];
509 p->buf[adaptA] = APESIGN(p->buf[delayA]);
510 p->buf[delayA - 1] = p->buf[delayA] - p->buf[delayA - 1];
511 p->buf[adaptA - 1] = APESIGN(p->buf[delayA - 1]);
512
513 predictionA = p->buf[delayA ] * p->coeffsA[filter][0] +
514 p->buf[delayA - 1] * p->coeffsA[filter][1] +
515 p->buf[delayA - 2] * p->coeffsA[filter][2] +
516 p->buf[delayA - 3] * p->coeffsA[filter][3];
517
518 /* Apply a scaled first-order filter compression */
519 p->buf[delayB] = p->filterA[filter ^ 1] - ((p->filterB[filter] * 31) >> 5);
520 p->buf[adaptB] = APESIGN(p->buf[delayB]);
521 p->buf[delayB - 1] = p->buf[delayB] - p->buf[delayB - 1];
522 p->buf[adaptB - 1] = APESIGN(p->buf[delayB - 1]);
523 p->filterB[filter] = p->filterA[filter ^ 1];
524
525 predictionB = p->buf[delayB ] * p->coeffsB[filter][0] +
526 p->buf[delayB - 1] * p->coeffsB[filter][1] +
527 p->buf[delayB - 2] * p->coeffsB[filter][2] +
528 p->buf[delayB - 3] * p->coeffsB[filter][3] +
529 p->buf[delayB - 4] * p->coeffsB[filter][4];
530
531 p->lastA[filter] = decoded + ((predictionA + (predictionB >> 1)) >> 10);
532 p->filterA[filter] = p->lastA[filter] + ((p->filterA[filter] * 31) >> 5);
533
534 if (!decoded) // no need updating filter coefficients
535 return p->filterA[filter];
536
537 if (decoded > 0) {
538 p->coeffsA[filter][0] -= p->buf[adaptA ];
539 p->coeffsA[filter][1] -= p->buf[adaptA - 1];
540 p->coeffsA[filter][2] -= p->buf[adaptA - 2];
541 p->coeffsA[filter][3] -= p->buf[adaptA - 3];
542
543 p->coeffsB[filter][0] -= p->buf[adaptB ];
544 p->coeffsB[filter][1] -= p->buf[adaptB - 1];
545 p->coeffsB[filter][2] -= p->buf[adaptB - 2];
546 p->coeffsB[filter][3] -= p->buf[adaptB - 3];
547 p->coeffsB[filter][4] -= p->buf[adaptB - 4];
548 } else {
549 p->coeffsA[filter][0] += p->buf[adaptA ];
550 p->coeffsA[filter][1] += p->buf[adaptA - 1];
551 p->coeffsA[filter][2] += p->buf[adaptA - 2];
552 p->coeffsA[filter][3] += p->buf[adaptA - 3];
553
554 p->coeffsB[filter][0] += p->buf[adaptB ];
555 p->coeffsB[filter][1] += p->buf[adaptB - 1];
556 p->coeffsB[filter][2] += p->buf[adaptB - 2];
557 p->coeffsB[filter][3] += p->buf[adaptB - 3];
558 p->coeffsB[filter][4] += p->buf[adaptB - 4];
559 }
560 return p->filterA[filter];
561 }
562
563 static void predictor_decode_stereo(APEContext * ctx, int count)
564 {
565 int32_t predictionA, predictionB;
566 APEPredictor *p = &ctx->predictor;
567 int32_t *decoded0 = ctx->decoded0;
568 int32_t *decoded1 = ctx->decoded1;
569
570 while (count--) {
571 /* Predictor Y */
572 predictionA = predictor_update_filter(p, *decoded0, 0, YDELAYA, YDELAYB, YADAPTCOEFFSA, YADAPTCOEFFSB);
573 predictionB = predictor_update_filter(p, *decoded1, 1, XDELAYA, XDELAYB, XADAPTCOEFFSA, XADAPTCOEFFSB);
574 *(decoded0++) = predictionA;
575 *(decoded1++) = predictionB;
576
577 /* Combined */
578 p->buf++;
579
580 /* Have we filled the history buffer? */
581 if (p->buf == p->historybuffer + HISTORY_SIZE) {
582 memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t));
583 p->buf = p->historybuffer;
584 }
585 }
586 }
587
588 static void predictor_decode_mono(APEContext * ctx, int count)
589 {
590 APEPredictor *p = &ctx->predictor;
591 int32_t *decoded0 = ctx->decoded0;
592 int32_t predictionA, currentA, A;
593
594 currentA = p->lastA[0];
595
596 while (count--) {
597 A = *decoded0;
598
599 p->buf[YDELAYA] = currentA;
600 p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1];
601
602 predictionA = p->buf[YDELAYA ] * p->coeffsA[0][0] +
603 p->buf[YDELAYA - 1] * p->coeffsA[0][1] +
604 p->buf[YDELAYA - 2] * p->coeffsA[0][2] +
605 p->buf[YDELAYA - 3] * p->coeffsA[0][3];
606
607 currentA = A + (predictionA >> 10);
608
609 p->buf[YADAPTCOEFFSA] = APESIGN(p->buf[YDELAYA ]);
610 p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]);
611
612 if (A > 0) {
613 p->coeffsA[0][0] -= p->buf[YADAPTCOEFFSA ];
614 p->coeffsA[0][1] -= p->buf[YADAPTCOEFFSA - 1];
615 p->coeffsA[0][2] -= p->buf[YADAPTCOEFFSA - 2];
616 p->coeffsA[0][3] -= p->buf[YADAPTCOEFFSA - 3];
617 } else if (A < 0) {
618 p->coeffsA[0][0] += p->buf[YADAPTCOEFFSA ];
619 p->coeffsA[0][1] += p->buf[YADAPTCOEFFSA - 1];
620 p->coeffsA[0][2] += p->buf[YADAPTCOEFFSA - 2];
621 p->coeffsA[0][3] += p->buf[YADAPTCOEFFSA - 3];
622 }
623
624 p->buf++;
625
626 /* Have we filled the history buffer? */
627 if (p->buf == p->historybuffer + HISTORY_SIZE) {
628 memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t));
629 p->buf = p->historybuffer;
630 }
631
632 p->filterA[0] = currentA + ((p->filterA[0] * 31) >> 5);
633 *(decoded0++) = p->filterA[0];
634 }
635
636 p->lastA[0] = currentA;
637 }
638
639 static void do_init_filter(APEFilter *f, int16_t * buf, int order)
640 {
641 f->coeffs = buf;
642 f->historybuffer = buf + order;
643 f->delay = f->historybuffer + order * 2;
644 f->adaptcoeffs = f->historybuffer + order;
645
646 memset(f->historybuffer, 0, (order * 2) * sizeof(int16_t));
647 memset(f->coeffs, 0, order * sizeof(int16_t));
648 f->avg = 0;
649 }
650
651 static void init_filter(APEContext * ctx, APEFilter *f, int16_t * buf, int order)
652 {
653 do_init_filter(&f[0], buf, order);
654 do_init_filter(&f[1], buf + order * 3 + HISTORY_SIZE, order);
655 }
656
657 static inline void do_apply_filter(APEContext * ctx, int version, APEFilter *f, int32_t *data, int count, int order, int fracbits)
658 {
659 int res;
660 int absres;
661
662 while (count--) {
663 /* round fixedpoint scalar product */
664 res = (ctx->dsp.scalarproduct_int16(f->delay - order, f->coeffs, order, 0) + (1 << (fracbits - 1))) >> fracbits;
665
666 if (*data < 0)
667 ctx->dsp.add_int16(f->coeffs, f->adaptcoeffs - order, order);
668 else if (*data > 0)
669 ctx->dsp.sub_int16(f->coeffs, f->adaptcoeffs - order, order);
670
671 res += *data;
672
673 *data++ = res;
674
675 /* Update the output history */
676 *f->delay++ = av_clip_int16(res);
677
678 if (version < 3980) {
679 /* Version ??? to < 3.98 files (untested) */
680 f->adaptcoeffs[0] = (res == 0) ? 0 : ((res >> 28) & 8) - 4;
681 f->adaptcoeffs[-4] >>= 1;
682 f->adaptcoeffs[-8] >>= 1;
683 } else {
684 /* Version 3.98 and later files */
685
686 /* Update the adaption coefficients */
687 absres = (res < 0 ? -res : res);
688
689 if (absres > (f->avg * 3))
690 *f->adaptcoeffs = ((res >> 25) & 64) - 32;
691 else if (absres > (f->avg * 4) / 3)
692 *f->adaptcoeffs = ((res >> 26) & 32) - 16;
693 else if (absres > 0)
694 *f->adaptcoeffs = ((res >> 27) & 16) - 8;
695 else
696 *f->adaptcoeffs = 0;
697
698 f->avg += (absres - f->avg) / 16;
699
700 f->adaptcoeffs[-1] >>= 1;
701 f->adaptcoeffs[-2] >>= 1;
702 f->adaptcoeffs[-8] >>= 1;
703 }
704
705 f->adaptcoeffs++;
706
707 /* Have we filled the history buffer? */
708 if (f->delay == f->historybuffer + HISTORY_SIZE + (order * 2)) {
709 memmove(f->historybuffer, f->delay - (order * 2),
710 (order * 2) * sizeof(int16_t));
711 f->delay = f->historybuffer + order * 2;
712 f->adaptcoeffs = f->historybuffer + order;
713 }
714 }
715 }
716
717 static void apply_filter(APEContext * ctx, APEFilter *f,
718 int32_t * data0, int32_t * data1,
719 int count, int order, int fracbits)
720 {
721 do_apply_filter(ctx, ctx->fileversion, &f[0], data0, count, order, fracbits);
722 if (data1)
723 do_apply_filter(ctx, ctx->fileversion, &f[1], data1, count, order, fracbits);
724 }
725
726 static void ape_apply_filters(APEContext * ctx, int32_t * decoded0,
727 int32_t * decoded1, int count)
728 {
729 int i;
730
731 for (i = 0; i < APE_FILTER_LEVELS; i++) {
732 if (!ape_filter_orders[ctx->fset][i])
733 break;
734 apply_filter(ctx, ctx->filters[i], decoded0, decoded1, count, ape_filter_orders[ctx->fset][i], ape_filter_fracbits[ctx->fset][i]);
735 }
736 }
737
738 static void init_frame_decoder(APEContext * ctx)
739 {
740 int i;
741 init_entropy_decoder(ctx);
742 init_predictor_decoder(ctx);
743
744 for (i = 0; i < APE_FILTER_LEVELS; i++) {
745 if (!ape_filter_orders[ctx->fset][i])
746 break;
747 init_filter(ctx, ctx->filters[i], ctx->filterbuf[i], ape_filter_orders[ctx->fset][i]);
748 }
749 }
750
751 static void ape_unpack_mono(APEContext * ctx, int count)
752 {
753 int32_t left;
754 int32_t *decoded0 = ctx->decoded0;
755 int32_t *decoded1 = ctx->decoded1;
756
757 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
758 entropy_decode(ctx, count, 0);
759 /* We are pure silence, so we're done. */
760 av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence mono\n");
761 return;
762 }
763
764 entropy_decode(ctx, count, 0);
765 ape_apply_filters(ctx, decoded0, NULL, count);
766
767 /* Now apply the predictor decoding */
768 predictor_decode_mono(ctx, count);
769
770 /* Pseudo-stereo - just copy left channel to right channel */
771 if (ctx->channels == 2) {
772 while (count--) {
773 left = *decoded0;
774 *(decoded1++) = *(decoded0++) = left;
775 }
776 }
777 }
778
779 static void ape_unpack_stereo(APEContext * ctx, int count)
780 {
781 int32_t left, right;
782 int32_t *decoded0 = ctx->decoded0;
783 int32_t *decoded1 = ctx->decoded1;
784
785 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
786 /* We are pure silence, so we're done. */
787 av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence stereo\n");
788 return;
789 }
790
791 entropy_decode(ctx, count, 1);
792 ape_apply_filters(ctx, decoded0, decoded1, count);
793
794 /* Now apply the predictor decoding */
795 predictor_decode_stereo(ctx, count);
796
797 /* Decorrelate and scale to output depth */
798 while (count--) {
799 left = *decoded1 - (*decoded0 / 2);
800 right = left + *decoded0;
801
802 *(decoded0++) = left;
803 *(decoded1++) = right;
804 }
805 }
806
807 static int ape_decode_frame(AVCodecContext * avctx,
808 void *data, int *data_size,
809 const uint8_t * buf, int buf_size)
810 {
811 APEContext *s = avctx->priv_data;
812 int16_t *samples = data;
813 int nblocks;
814 int i, n;
815 int blockstodecode;
816 int bytes_used;
817
818 if (buf_size == 0 && !s->samples) {
819 *data_size = 0;
820 return 0;
821 }
822
823 /* should not happen but who knows */
824 if (BLOCKS_PER_LOOP * 2 * avctx->channels > *data_size) {
825 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);
826 return -1;
827 }
828
829 if(!s->samples){
830 s->data = av_realloc(s->data, (buf_size + 3) & ~3);
831 s->dsp.bswap_buf((uint32_t*)s->data, (const uint32_t*)buf, buf_size >> 2);
832 s->ptr = s->last_ptr = s->data;
833 s->data_end = s->data + buf_size;
834
835 nblocks = s->samples = bytestream_get_be32(&s->ptr);
836 n = bytestream_get_be32(&s->ptr);
837 if(n < 0 || n > 3){
838 av_log(avctx, AV_LOG_ERROR, "Incorrect offset passed\n");
839 s->data = NULL;
840 return -1;
841 }
842 s->ptr += n;
843
844 s->currentframeblocks = nblocks;
845 buf += 4;
846 if (s->samples <= 0) {
847 *data_size = 0;
848 return buf_size;
849 }
850
851 memset(s->decoded0, 0, sizeof(s->decoded0));
852 memset(s->decoded1, 0, sizeof(s->decoded1));
853
854 /* Initialize the frame decoder */
855 init_frame_decoder(s);
856 }
857
858 if (!s->data) {
859 *data_size = 0;
860 return buf_size;
861 }
862
863 nblocks = s->samples;
864 blockstodecode = FFMIN(BLOCKS_PER_LOOP, nblocks);
865
866 s->error=0;
867
868 if ((s->channels == 1) || (s->frameflags & APE_FRAMECODE_PSEUDO_STEREO))
869 ape_unpack_mono(s, blockstodecode);
870 else
871 ape_unpack_stereo(s, blockstodecode);
872
873 if(s->error || s->ptr > s->data_end){
874 s->samples=0;
875 av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n");
876 return -1;
877 }
878
879 for (i = 0; i < blockstodecode; i++) {
880 *samples++ = s->decoded0[i];
881 if(s->channels == 2)
882 *samples++ = s->decoded1[i];
883 }
884
885 s->samples -= blockstodecode;
886
887 *data_size = blockstodecode * 2 * s->channels;
888 bytes_used = s->samples ? s->ptr - s->last_ptr : buf_size;
889 s->last_ptr = s->ptr;
890 return bytes_used;
891 }
892
893 AVCodec ape_decoder = {
894 "ape",
895 CODEC_TYPE_AUDIO,
896 CODEC_ID_APE,
897 sizeof(APEContext),
898 ape_decode_init,
899 NULL,
900 ape_decode_close,
901 ape_decode_frame,
902 .long_name = NULL_IF_CONFIG_SMALL("Monkey's Audio"),
903 };
lucabe's unfinished and experimental patches for ffmpeg