2 * Monkey's Audio lossless audio decoder
3 * Copyright (c) 2007 Benjamin Zores <ben@geexbox.org>
4 * based upon libdemac from Dave Chapman.
6 * This file is part of FFmpeg.
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.
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.
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
23 #define ALT_BITSTREAM_READER_LE
27 #include "bytestream.h"
31 * Monkey's Audio lossless audio decoder
34 #define BLOCKS_PER_LOOP 4608
35 #define MAX_CHANNELS 2
36 #define MAX_BYTESPERSAMPLE 3
38 #define APE_FRAMECODE_MONO_SILENCE 1
39 #define APE_FRAMECODE_STEREO_SILENCE 3
40 #define APE_FRAMECODE_PSEUDO_STEREO 4
42 #define HISTORY_SIZE 512
43 #define PREDICTOR_ORDER 8
44 /** Total size of all predictor histories */
45 #define PREDICTOR_SIZE 50
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)
52 #define YADAPTCOEFFSA 18
53 #define XADAPTCOEFFSA 14
54 #define YADAPTCOEFFSB 10
55 #define XADAPTCOEFFSB 5
58 * Possible compression levels
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
70 #define APE_FILTER_LEVELS 3
72 /** Filter orders depending on compression level */
73 static const uint16_t ape_filter_orders[5][APE_FILTER_LEVELS] = {
81 /** Filter fraction bits depending on compression level */
82 static const uint8_t ape_filter_fracbits[5][APE_FILTER_LEVELS] = {
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
101 typedef struct APERice {
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
113 /** Filter histories */
114 typedef struct APEPredictor {
122 int32_t coeffsA[2][4]; ///< adaption coefficients
123 int32_t coeffsB[2][5]; ///< adaption coefficients
124 int32_t historybuffer[HISTORY_SIZE + PREDICTOR_SIZE];
127 /** Decoder context */
128 typedef struct APEContext {
129 AVCodecContext *avctx;
132 int samples; ///< samples left to decode in current frame
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
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
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
148 int16_t* filterbuf[APE_FILTER_LEVELS]; ///< filter memory
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
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
165 static av_cold int ape_decode_init(AVCodecContext * avctx)
167 APEContext *s = avctx->priv_data;
170 if (avctx->extradata_size != 6) {
171 av_log(avctx, AV_LOG_ERROR, "Incorrect extradata\n");
174 if (avctx->bits_per_coded_sample != 16) {
175 av_log(avctx, AV_LOG_ERROR, "Only 16-bit samples are supported\n");
178 if (avctx->channels > 2) {
179 av_log(avctx, AV_LOG_ERROR, "Only mono and stereo is supported\n");
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);
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);
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])
197 s->filterbuf[i] = av_malloc((ape_filter_orders[s->fset][i] * 3 + HISTORY_SIZE) * 4);
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;
206 static av_cold int ape_decode_close(AVCodecContext * avctx)
208 APEContext *s = avctx->priv_data;
211 for (i = 0; i < APE_FILTER_LEVELS; i++)
212 av_freep(&s->filterbuf[i]);
219 * @defgroup rangecoder APE range decoder
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)
229 /** Start the decoder */
230 static inline void range_start_decoding(APEContext * ctx)
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;
237 /** Perform normalization */
238 static inline void range_dec_normalize(APEContext * ctx)
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;
245 ctx->rc.low = (ctx->rc.low << 8) | ((ctx->rc.buffer >> 1) & 0xFF);
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
256 static inline int range_decode_culfreq(APEContext * ctx, int tot_f)
258 range_dec_normalize(ctx);
259 ctx->rc.help = ctx->rc.range / tot_f;
260 return ctx->rc.low / ctx->rc.help;
264 * Decode value with given size in bits
265 * @param ctx decoder context
266 * @param shift number of bits to decode
268 static inline int range_decode_culshift(APEContext * ctx, int shift)
270 range_dec_normalize(ctx);
271 ctx->rc.help = ctx->rc.range >> shift;
272 return ctx->rc.low / ctx->rc.help;
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)
282 static inline void range_decode_update(APEContext * ctx, int sy_f, int lt_f)
284 ctx->rc.low -= ctx->rc.help * lt_f;
285 ctx->rc.range = ctx->rc.help * sy_f;
288 /** Decode n bits (n <= 16) without modelling */
289 static inline int range_decode_bits(APEContext * ctx, int n)
291 int sym = range_decode_culshift(ctx, n);
292 range_decode_update(ctx, 1, sym);
297 #define MODEL_ELEMENTS 64
300 * Fixed probabilities for symbols in Monkey Audio version 3.97
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,
309 * Probability ranges for symbols in Monkey Audio version 3.97
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,
318 * Fixed probabilities for symbols in Monkey Audio version 3.98
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,
327 * Probability ranges for symbols in Monkey Audio version 3.98
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,
337 * @param ctx decoder context
338 * @param counts probability range start position
339 * @param counts_diff probability range widths
341 static inline int range_get_symbol(APEContext * ctx,
342 const uint16_t counts[],
343 const uint16_t counts_diff[])
347 cf = range_decode_culshift(ctx, 16);
350 symbol= cf - 65535 + 63;
351 range_decode_update(ctx, 1, cf);
356 /* figure out the symbol inefficiently; a binary search would be much better */
357 for (symbol = 0; counts[symbol + 1] <= cf; symbol++);
359 range_decode_update(ctx, counts_diff[symbol], counts[symbol]);
363 /** @} */ // group rangecoder
365 static inline void update_rice(APERice *rice, int x)
367 int lim = rice->k ? (1 << (rice->k + 4)) : 0;
368 rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5);
370 if (rice->ksum < lim)
372 else if (rice->ksum >= (1 << (rice->k + 5)))
376 static inline int ape_decode_value(APEContext * ctx, APERice *rice)
380 if (ctx->fileversion < 3990) {
383 overflow = range_get_symbol(ctx, counts_3970, counts_diff_3970);
385 if (overflow == (MODEL_ELEMENTS - 1)) {
386 tmpk = range_decode_bits(ctx, 5);
389 tmpk = (rice->k < 1) ? 0 : rice->k - 1;
392 x = range_decode_bits(ctx, tmpk);
394 x = range_decode_bits(ctx, 16);
395 x |= (range_decode_bits(ctx, tmpk - 16) << 16);
397 x += overflow << tmpk;
401 pivot = rice->ksum >> 5;
405 overflow = range_get_symbol(ctx, counts_3980, counts_diff_3980);
407 if (overflow == (MODEL_ELEMENTS - 1)) {
408 overflow = range_decode_bits(ctx, 16) << 16;
409 overflow |= range_decode_bits(ctx, 16);
412 if (pivot < 0x10000) {
413 base = range_decode_culfreq(ctx, pivot);
414 range_decode_update(ctx, 1, base);
416 int base_hi = pivot, base_lo;
419 while (base_hi & ~0xFFFF) {
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);
428 base = (base_hi << bbits) + base_lo;
431 x = base + overflow * pivot;
434 update_rice(rice, x);
436 /* Convert to signed */
443 static void entropy_decode(APEContext * ctx, int blockstodecode, int stereo)
445 int32_t *decoded0 = ctx->decoded0;
446 int32_t *decoded1 = ctx->decoded1;
448 ctx->blocksdecoded = blockstodecode;
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));
455 while (blockstodecode--) {
456 *decoded0++ = ape_decode_value(ctx, &ctx->riceY);
458 *decoded1++ = ape_decode_value(ctx, &ctx->riceX);
462 if (ctx->blocksdecoded == ctx->currentframeblocks)
463 range_dec_normalize(ctx); /* normalize to use up all bytes */
466 static void init_entropy_decoder(APEContext * ctx)
469 ctx->CRC = bytestream_get_be32(&ctx->ptr);
471 /* Read the frame flags if they exist */
473 if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) {
474 ctx->CRC &= ~0x80000000;
476 ctx->frameflags = bytestream_get_be32(&ctx->ptr);
479 /* Keep a count of the blocks decoded in this frame */
480 ctx->blocksdecoded = 0;
482 /* Initialize the rice structs */
484 ctx->riceX.ksum = (1 << ctx->riceX.k) * 16;
486 ctx->riceY.ksum = (1 << ctx->riceY.k) * 16;
488 /* The first 8 bits of input are ignored. */
491 range_start_decoding(ctx);
494 static const int32_t initial_coeffs[4] = {
498 static void init_predictor_decoder(APEContext * ctx)
500 APEPredictor *p = &ctx->predictor;
502 /* Zero the history buffers */
503 memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t));
504 p->buf = p->historybuffer;
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));
511 p->filterA[0] = p->filterA[1] = 0;
512 p->filterB[0] = p->filterB[1] = 0;
513 p->lastA[0] = p->lastA[1] = 0;
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);
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)
523 int32_t predictionA, predictionB, sign;
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]);
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];
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];
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];
548 p->lastA[filter] = decoded + ((predictionA + (predictionB >> 1)) >> 10);
549 p->filterA[filter] = p->lastA[filter] + ((p->filterA[filter] * 31) >> 5);
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;
562 return p->filterA[filter];
565 static void predictor_decode_stereo(APEContext * ctx, int count)
567 APEPredictor *p = &ctx->predictor;
568 int32_t *decoded0 = ctx->decoded0;
569 int32_t *decoded1 = ctx->decoded1;
573 *decoded0 = predictor_update_filter(p, *decoded0, 0, YDELAYA, YDELAYB, YADAPTCOEFFSA, YADAPTCOEFFSB);
575 *decoded1 = predictor_update_filter(p, *decoded1, 1, XDELAYA, XDELAYB, XADAPTCOEFFSA, XADAPTCOEFFSB);
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;
589 static void predictor_decode_mono(APEContext * ctx, int count)
591 APEPredictor *p = &ctx->predictor;
592 int32_t *decoded0 = ctx->decoded0;
593 int32_t predictionA, currentA, A, sign;
595 currentA = p->lastA[0];
600 p->buf[YDELAYA] = currentA;
601 p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1];
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];
608 currentA = A + (predictionA >> 10);
610 p->buf[YADAPTCOEFFSA] = APESIGN(p->buf[YDELAYA ]);
611 p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]);
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;
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;
627 p->filterA[0] = currentA + ((p->filterA[0] * 31) >> 5);
628 *(decoded0++) = p->filterA[0];
631 p->lastA[0] = currentA;
634 static void do_init_filter(APEFilter *f, int16_t * buf, int order)
637 f->historybuffer = buf + order;
638 f->delay = f->historybuffer + order * 2;
639 f->adaptcoeffs = f->historybuffer + order;
641 memset(f->historybuffer, 0, (order * 2) * sizeof(int16_t));
642 memset(f->coeffs, 0, order * sizeof(int16_t));
646 static void init_filter(APEContext * ctx, APEFilter *f, int16_t * buf, int order)
648 do_init_filter(&f[0], buf, order);
649 do_init_filter(&f[1], buf + order * 3 + HISTORY_SIZE, order);
652 static void do_apply_filter(APEContext * ctx, int version, APEFilter *f, int32_t *data, int count, int order, int fracbits)
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;
664 /* Update the output history */
665 *f->delay++ = av_clip_int16(res);
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;
673 /* Version 3.98 and later files */
675 /* Update the adaption coefficients */
678 *f->adaptcoeffs = ((res & (1<<31)) - (1<<30)) >> (25 + (absres <= f->avg*3) + (absres <= f->avg*4/3));
682 f->avg += (absres - f->avg) / 16;
684 f->adaptcoeffs[-1] >>= 1;
685 f->adaptcoeffs[-2] >>= 1;
686 f->adaptcoeffs[-8] >>= 1;
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;
701 static void apply_filter(APEContext * ctx, APEFilter *f,
702 int32_t * data0, int32_t * data1,
703 int count, int order, int fracbits)
705 do_apply_filter(ctx, ctx->fileversion, &f[0], data0, count, order, fracbits);
707 do_apply_filter(ctx, ctx->fileversion, &f[1], data1, count, order, fracbits);
710 static void ape_apply_filters(APEContext * ctx, int32_t * decoded0,
711 int32_t * decoded1, int count)
715 for (i = 0; i < APE_FILTER_LEVELS; i++) {
716 if (!ape_filter_orders[ctx->fset][i])
718 apply_filter(ctx, ctx->filters[i], decoded0, decoded1, count, ape_filter_orders[ctx->fset][i], ape_filter_fracbits[ctx->fset][i]);
722 static void init_frame_decoder(APEContext * ctx)
725 init_entropy_decoder(ctx);
726 init_predictor_decoder(ctx);
728 for (i = 0; i < APE_FILTER_LEVELS; i++) {
729 if (!ape_filter_orders[ctx->fset][i])
731 init_filter(ctx, ctx->filters[i], ctx->filterbuf[i], ape_filter_orders[ctx->fset][i]);
735 static void ape_unpack_mono(APEContext * ctx, int count)
738 int32_t *decoded0 = ctx->decoded0;
739 int32_t *decoded1 = ctx->decoded1;
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");
748 entropy_decode(ctx, count, 0);
749 ape_apply_filters(ctx, decoded0, NULL, count);
751 /* Now apply the predictor decoding */
752 predictor_decode_mono(ctx, count);
754 /* Pseudo-stereo - just copy left channel to right channel */
755 if (ctx->channels == 2) {
758 *(decoded1++) = *(decoded0++) = left;
763 static void ape_unpack_stereo(APEContext * ctx, int count)
766 int32_t *decoded0 = ctx->decoded0;
767 int32_t *decoded1 = ctx->decoded1;
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");
775 entropy_decode(ctx, count, 1);
776 ape_apply_filters(ctx, decoded0, decoded1, count);
778 /* Now apply the predictor decoding */
779 predictor_decode_stereo(ctx, count);
781 /* Decorrelate and scale to output depth */
783 left = *decoded1 - (*decoded0 / 2);
784 right = left + *decoded0;
786 *(decoded0++) = left;
787 *(decoded1++) = right;
791 static int ape_decode_frame(AVCodecContext * avctx,
792 void *data, int *data_size,
795 const uint8_t *buf = avpkt->data;
796 int buf_size = avpkt->size;
797 APEContext *s = avctx->priv_data;
798 int16_t *samples = data;
804 if (buf_size == 0 && !s->samples) {
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);
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;
821 nblocks = s->samples = bytestream_get_be32(&s->ptr);
822 n = bytestream_get_be32(&s->ptr);
824 av_log(avctx, AV_LOG_ERROR, "Incorrect offset passed\n");
830 s->currentframeblocks = nblocks;
832 if (s->samples <= 0) {
837 memset(s->decoded0, 0, sizeof(s->decoded0));
838 memset(s->decoded1, 0, sizeof(s->decoded1));
840 /* Initialize the frame decoder */
841 init_frame_decoder(s);
849 nblocks = s->samples;
850 blockstodecode = FFMIN(BLOCKS_PER_LOOP, nblocks);
854 if ((s->channels == 1) || (s->frameflags & APE_FRAMECODE_PSEUDO_STEREO))
855 ape_unpack_mono(s, blockstodecode);
857 ape_unpack_stereo(s, blockstodecode);
860 if(s->error || s->ptr > s->data_end){
862 av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n");
866 for (i = 0; i < blockstodecode; i++) {
867 *samples++ = s->decoded0[i];
869 *samples++ = s->decoded1[i];
872 s->samples -= blockstodecode;
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;
880 AVCodec ape_decoder = {
889 .capabilities = CODEC_CAP_SUBFRAMES,
890 .long_name = NULL_IF_CONFIG_SMALL("Monkey's Audio"),