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"
28 #include "libavutil/audioconvert.h"
32 * Monkey's Audio lossless audio decoder
35 #define BLOCKS_PER_LOOP 4608
36 #define MAX_CHANNELS 2
37 #define MAX_BYTESPERSAMPLE 3
39 #define APE_FRAMECODE_MONO_SILENCE 1
40 #define APE_FRAMECODE_STEREO_SILENCE 3
41 #define APE_FRAMECODE_PSEUDO_STEREO 4
43 #define HISTORY_SIZE 512
44 #define PREDICTOR_ORDER 8
45 /** Total size of all predictor histories */
46 #define PREDICTOR_SIZE 50
48 #define YDELAYA (18 + PREDICTOR_ORDER*4)
49 #define YDELAYB (18 + PREDICTOR_ORDER*3)
50 #define XDELAYA (18 + PREDICTOR_ORDER*2)
51 #define XDELAYB (18 + PREDICTOR_ORDER)
53 #define YADAPTCOEFFSA 18
54 #define XADAPTCOEFFSA 14
55 #define YADAPTCOEFFSB 10
56 #define XADAPTCOEFFSB 5
59 * Possible compression levels
62 enum APECompressionLevel {
63 COMPRESSION_LEVEL_FAST = 1000,
64 COMPRESSION_LEVEL_NORMAL = 2000,
65 COMPRESSION_LEVEL_HIGH = 3000,
66 COMPRESSION_LEVEL_EXTRA_HIGH = 4000,
67 COMPRESSION_LEVEL_INSANE = 5000
71 #define APE_FILTER_LEVELS 3
73 /** Filter orders depending on compression level */
74 static const uint16_t ape_filter_orders[5][APE_FILTER_LEVELS] = {
82 /** Filter fraction bits depending on compression level */
83 static const uint8_t ape_filter_fracbits[5][APE_FILTER_LEVELS] = {
92 /** Filters applied to the decoded data */
93 typedef struct APEFilter {
94 int16_t *coeffs; ///< actual coefficients used in filtering
95 int16_t *adaptcoeffs; ///< adaptive filter coefficients used for correcting of actual filter coefficients
96 int16_t *historybuffer; ///< filter memory
97 int16_t *delay; ///< filtered values
102 typedef struct APERice {
107 typedef struct APERangecoder {
108 uint32_t low; ///< low end of interval
109 uint32_t range; ///< length of interval
110 uint32_t help; ///< bytes_to_follow resp. intermediate value
111 unsigned int buffer; ///< buffer for input/output
114 /** Filter histories */
115 typedef struct APEPredictor {
123 int32_t coeffsA[2][4]; ///< adaption coefficients
124 int32_t coeffsB[2][5]; ///< adaption coefficients
125 int32_t historybuffer[HISTORY_SIZE + PREDICTOR_SIZE];
128 /** Decoder context */
129 typedef struct APEContext {
130 AVCodecContext *avctx;
133 int samples; ///< samples left to decode in current frame
135 int fileversion; ///< codec version, very important in decoding process
136 int compression_level; ///< compression levels
137 int fset; ///< which filter set to use (calculated from compression level)
138 int flags; ///< global decoder flags
140 uint32_t CRC; ///< frame CRC
141 int frameflags; ///< frame flags
142 int currentframeblocks; ///< samples (per channel) in current frame
143 int blocksdecoded; ///< count of decoded samples in current frame
144 APEPredictor predictor; ///< predictor used for final reconstruction
146 int32_t decoded0[BLOCKS_PER_LOOP]; ///< decoded data for the first channel
147 int32_t decoded1[BLOCKS_PER_LOOP]; ///< decoded data for the second channel
149 int16_t* filterbuf[APE_FILTER_LEVELS]; ///< filter memory
151 APERangecoder rc; ///< rangecoder used to decode actual values
152 APERice riceX; ///< rice code parameters for the second channel
153 APERice riceY; ///< rice code parameters for the first channel
154 APEFilter filters[APE_FILTER_LEVELS][2]; ///< filters used for reconstruction
156 uint8_t *data; ///< current frame data
157 uint8_t *data_end; ///< frame data end
158 const uint8_t *ptr; ///< current position in frame data
159 const uint8_t *last_ptr; ///< position where last 4608-sample block ended
166 static av_cold int ape_decode_init(AVCodecContext * avctx)
168 APEContext *s = avctx->priv_data;
171 if (avctx->extradata_size != 6) {
172 av_log(avctx, AV_LOG_ERROR, "Incorrect extradata\n");
175 if (avctx->bits_per_coded_sample != 16) {
176 av_log(avctx, AV_LOG_ERROR, "Only 16-bit samples are supported\n");
179 if (avctx->channels > 2) {
180 av_log(avctx, AV_LOG_ERROR, "Only mono and stereo is supported\n");
184 s->channels = avctx->channels;
185 s->fileversion = AV_RL16(avctx->extradata);
186 s->compression_level = AV_RL16(avctx->extradata + 2);
187 s->flags = AV_RL16(avctx->extradata + 4);
189 av_log(avctx, AV_LOG_DEBUG, "Compression Level: %d - Flags: %d\n", s->compression_level, s->flags);
190 if (s->compression_level % 1000 || s->compression_level > COMPRESSION_LEVEL_INSANE) {
191 av_log(avctx, AV_LOG_ERROR, "Incorrect compression level %d\n", s->compression_level);
194 s->fset = s->compression_level / 1000 - 1;
195 for (i = 0; i < APE_FILTER_LEVELS; i++) {
196 if (!ape_filter_orders[s->fset][i])
198 s->filterbuf[i] = av_malloc((ape_filter_orders[s->fset][i] * 3 + HISTORY_SIZE) * 4);
201 dsputil_init(&s->dsp, avctx);
202 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
203 avctx->channel_layout = (avctx->channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
207 static av_cold int ape_decode_close(AVCodecContext * avctx)
209 APEContext *s = avctx->priv_data;
212 for (i = 0; i < APE_FILTER_LEVELS; i++)
213 av_freep(&s->filterbuf[i]);
220 * @defgroup rangecoder APE range decoder
225 #define TOP_VALUE ((unsigned int)1 << (CODE_BITS-1))
226 #define SHIFT_BITS (CODE_BITS - 9)
227 #define EXTRA_BITS ((CODE_BITS-2) % 8 + 1)
228 #define BOTTOM_VALUE (TOP_VALUE >> 8)
230 /** Start the decoder */
231 static inline void range_start_decoding(APEContext * ctx)
233 ctx->rc.buffer = bytestream_get_byte(&ctx->ptr);
234 ctx->rc.low = ctx->rc.buffer >> (8 - EXTRA_BITS);
235 ctx->rc.range = (uint32_t) 1 << EXTRA_BITS;
238 /** Perform normalization */
239 static inline void range_dec_normalize(APEContext * ctx)
241 while (ctx->rc.range <= BOTTOM_VALUE) {
242 ctx->rc.buffer <<= 8;
243 if(ctx->ptr < ctx->data_end)
244 ctx->rc.buffer += *ctx->ptr;
246 ctx->rc.low = (ctx->rc.low << 8) | ((ctx->rc.buffer >> 1) & 0xFF);
252 * Calculate culmulative frequency for next symbol. Does NO update!
253 * @param ctx decoder context
254 * @param tot_f is the total frequency or (code_value)1<<shift
255 * @return the culmulative frequency
257 static inline int range_decode_culfreq(APEContext * ctx, int tot_f)
259 range_dec_normalize(ctx);
260 ctx->rc.help = ctx->rc.range / tot_f;
261 return ctx->rc.low / ctx->rc.help;
265 * Decode value with given size in bits
266 * @param ctx decoder context
267 * @param shift number of bits to decode
269 static inline int range_decode_culshift(APEContext * ctx, int shift)
271 range_dec_normalize(ctx);
272 ctx->rc.help = ctx->rc.range >> shift;
273 return ctx->rc.low / ctx->rc.help;
278 * Update decoding state
279 * @param ctx decoder context
280 * @param sy_f the interval length (frequency of the symbol)
281 * @param lt_f the lower end (frequency sum of < symbols)
283 static inline void range_decode_update(APEContext * ctx, int sy_f, int lt_f)
285 ctx->rc.low -= ctx->rc.help * lt_f;
286 ctx->rc.range = ctx->rc.help * sy_f;
289 /** Decode n bits (n <= 16) without modelling */
290 static inline int range_decode_bits(APEContext * ctx, int n)
292 int sym = range_decode_culshift(ctx, n);
293 range_decode_update(ctx, 1, sym);
298 #define MODEL_ELEMENTS 64
301 * Fixed probabilities for symbols in Monkey Audio version 3.97
303 static const uint16_t counts_3970[22] = {
304 0, 14824, 28224, 39348, 47855, 53994, 58171, 60926,
305 62682, 63786, 64463, 64878, 65126, 65276, 65365, 65419,
306 65450, 65469, 65480, 65487, 65491, 65493,
310 * Probability ranges for symbols in Monkey Audio version 3.97
312 static const uint16_t counts_diff_3970[21] = {
313 14824, 13400, 11124, 8507, 6139, 4177, 2755, 1756,
314 1104, 677, 415, 248, 150, 89, 54, 31,
319 * Fixed probabilities for symbols in Monkey Audio version 3.98
321 static const uint16_t counts_3980[22] = {
322 0, 19578, 36160, 48417, 56323, 60899, 63265, 64435,
323 64971, 65232, 65351, 65416, 65447, 65466, 65476, 65482,
324 65485, 65488, 65490, 65491, 65492, 65493,
328 * Probability ranges for symbols in Monkey Audio version 3.98
330 static const uint16_t counts_diff_3980[21] = {
331 19578, 16582, 12257, 7906, 4576, 2366, 1170, 536,
332 261, 119, 65, 31, 19, 10, 6, 3,
338 * @param ctx decoder context
339 * @param counts probability range start position
340 * @param counts_diff probability range widths
342 static inline int range_get_symbol(APEContext * ctx,
343 const uint16_t counts[],
344 const uint16_t counts_diff[])
348 cf = range_decode_culshift(ctx, 16);
351 symbol= cf - 65535 + 63;
352 range_decode_update(ctx, 1, cf);
357 /* figure out the symbol inefficiently; a binary search would be much better */
358 for (symbol = 0; counts[symbol + 1] <= cf; symbol++);
360 range_decode_update(ctx, counts_diff[symbol], counts[symbol]);
364 /** @} */ // group rangecoder
366 static inline void update_rice(APERice *rice, int x)
368 int lim = rice->k ? (1 << (rice->k + 4)) : 0;
369 rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5);
371 if (rice->ksum < lim)
373 else if (rice->ksum >= (1 << (rice->k + 5)))
377 static inline int ape_decode_value(APEContext * ctx, APERice *rice)
381 if (ctx->fileversion < 3990) {
384 overflow = range_get_symbol(ctx, counts_3970, counts_diff_3970);
386 if (overflow == (MODEL_ELEMENTS - 1)) {
387 tmpk = range_decode_bits(ctx, 5);
390 tmpk = (rice->k < 1) ? 0 : rice->k - 1;
393 x = range_decode_bits(ctx, tmpk);
395 x = range_decode_bits(ctx, 16);
396 x |= (range_decode_bits(ctx, tmpk - 16) << 16);
398 x += overflow << tmpk;
402 pivot = rice->ksum >> 5;
406 overflow = range_get_symbol(ctx, counts_3980, counts_diff_3980);
408 if (overflow == (MODEL_ELEMENTS - 1)) {
409 overflow = range_decode_bits(ctx, 16) << 16;
410 overflow |= range_decode_bits(ctx, 16);
413 if (pivot < 0x10000) {
414 base = range_decode_culfreq(ctx, pivot);
415 range_decode_update(ctx, 1, base);
417 int base_hi = pivot, base_lo;
420 while (base_hi & ~0xFFFF) {
424 base_hi = range_decode_culfreq(ctx, base_hi + 1);
425 range_decode_update(ctx, 1, base_hi);
426 base_lo = range_decode_culfreq(ctx, 1 << bbits);
427 range_decode_update(ctx, 1, base_lo);
429 base = (base_hi << bbits) + base_lo;
432 x = base + overflow * pivot;
435 update_rice(rice, x);
437 /* Convert to signed */
444 static void entropy_decode(APEContext * ctx, int blockstodecode, int stereo)
446 int32_t *decoded0 = ctx->decoded0;
447 int32_t *decoded1 = ctx->decoded1;
449 ctx->blocksdecoded = blockstodecode;
451 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
452 /* We are pure silence, just memset the output buffer. */
453 memset(decoded0, 0, blockstodecode * sizeof(int32_t));
454 memset(decoded1, 0, blockstodecode * sizeof(int32_t));
456 while (blockstodecode--) {
457 *decoded0++ = ape_decode_value(ctx, &ctx->riceY);
459 *decoded1++ = ape_decode_value(ctx, &ctx->riceX);
463 if (ctx->blocksdecoded == ctx->currentframeblocks)
464 range_dec_normalize(ctx); /* normalize to use up all bytes */
467 static void init_entropy_decoder(APEContext * ctx)
470 ctx->CRC = bytestream_get_be32(&ctx->ptr);
472 /* Read the frame flags if they exist */
474 if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) {
475 ctx->CRC &= ~0x80000000;
477 ctx->frameflags = bytestream_get_be32(&ctx->ptr);
480 /* Keep a count of the blocks decoded in this frame */
481 ctx->blocksdecoded = 0;
483 /* Initialize the rice structs */
485 ctx->riceX.ksum = (1 << ctx->riceX.k) * 16;
487 ctx->riceY.ksum = (1 << ctx->riceY.k) * 16;
489 /* The first 8 bits of input are ignored. */
492 range_start_decoding(ctx);
495 static const int32_t initial_coeffs[4] = {
499 static void init_predictor_decoder(APEContext * ctx)
501 APEPredictor *p = &ctx->predictor;
503 /* Zero the history buffers */
504 memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t));
505 p->buf = p->historybuffer;
507 /* Initialize and zero the coefficients */
508 memcpy(p->coeffsA[0], initial_coeffs, sizeof(initial_coeffs));
509 memcpy(p->coeffsA[1], initial_coeffs, sizeof(initial_coeffs));
510 memset(p->coeffsB, 0, sizeof(p->coeffsB));
512 p->filterA[0] = p->filterA[1] = 0;
513 p->filterB[0] = p->filterB[1] = 0;
514 p->lastA[0] = p->lastA[1] = 0;
517 /** Get inverse sign of integer (-1 for positive, 1 for negative and 0 for zero) */
518 static inline int APESIGN(int32_t x) {
519 return (x < 0) - (x > 0);
522 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)
524 int32_t predictionA, predictionB, sign;
526 p->buf[delayA] = p->lastA[filter];
527 p->buf[adaptA] = APESIGN(p->buf[delayA]);
528 p->buf[delayA - 1] = p->buf[delayA] - p->buf[delayA - 1];
529 p->buf[adaptA - 1] = APESIGN(p->buf[delayA - 1]);
531 predictionA = p->buf[delayA ] * p->coeffsA[filter][0] +
532 p->buf[delayA - 1] * p->coeffsA[filter][1] +
533 p->buf[delayA - 2] * p->coeffsA[filter][2] +
534 p->buf[delayA - 3] * p->coeffsA[filter][3];
536 /* Apply a scaled first-order filter compression */
537 p->buf[delayB] = p->filterA[filter ^ 1] - ((p->filterB[filter] * 31) >> 5);
538 p->buf[adaptB] = APESIGN(p->buf[delayB]);
539 p->buf[delayB - 1] = p->buf[delayB] - p->buf[delayB - 1];
540 p->buf[adaptB - 1] = APESIGN(p->buf[delayB - 1]);
541 p->filterB[filter] = p->filterA[filter ^ 1];
543 predictionB = p->buf[delayB ] * p->coeffsB[filter][0] +
544 p->buf[delayB - 1] * p->coeffsB[filter][1] +
545 p->buf[delayB - 2] * p->coeffsB[filter][2] +
546 p->buf[delayB - 3] * p->coeffsB[filter][3] +
547 p->buf[delayB - 4] * p->coeffsB[filter][4];
549 p->lastA[filter] = decoded + ((predictionA + (predictionB >> 1)) >> 10);
550 p->filterA[filter] = p->lastA[filter] + ((p->filterA[filter] * 31) >> 5);
552 sign = APESIGN(decoded);
553 p->coeffsA[filter][0] += p->buf[adaptA ] * sign;
554 p->coeffsA[filter][1] += p->buf[adaptA - 1] * sign;
555 p->coeffsA[filter][2] += p->buf[adaptA - 2] * sign;
556 p->coeffsA[filter][3] += p->buf[adaptA - 3] * sign;
557 p->coeffsB[filter][0] += p->buf[adaptB ] * sign;
558 p->coeffsB[filter][1] += p->buf[adaptB - 1] * sign;
559 p->coeffsB[filter][2] += p->buf[adaptB - 2] * sign;
560 p->coeffsB[filter][3] += p->buf[adaptB - 3] * sign;
561 p->coeffsB[filter][4] += p->buf[adaptB - 4] * sign;
563 return p->filterA[filter];
566 static void predictor_decode_stereo(APEContext * ctx, int count)
568 APEPredictor *p = &ctx->predictor;
569 int32_t *decoded0 = ctx->decoded0;
570 int32_t *decoded1 = ctx->decoded1;
574 *decoded0 = predictor_update_filter(p, *decoded0, 0, YDELAYA, YDELAYB, YADAPTCOEFFSA, YADAPTCOEFFSB);
576 *decoded1 = predictor_update_filter(p, *decoded1, 1, XDELAYA, XDELAYB, XADAPTCOEFFSA, XADAPTCOEFFSB);
582 /* Have we filled the history buffer? */
583 if (p->buf == p->historybuffer + HISTORY_SIZE) {
584 memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t));
585 p->buf = p->historybuffer;
590 static void predictor_decode_mono(APEContext * ctx, int count)
592 APEPredictor *p = &ctx->predictor;
593 int32_t *decoded0 = ctx->decoded0;
594 int32_t predictionA, currentA, A, sign;
596 currentA = p->lastA[0];
601 p->buf[YDELAYA] = currentA;
602 p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1];
604 predictionA = p->buf[YDELAYA ] * p->coeffsA[0][0] +
605 p->buf[YDELAYA - 1] * p->coeffsA[0][1] +
606 p->buf[YDELAYA - 2] * p->coeffsA[0][2] +
607 p->buf[YDELAYA - 3] * p->coeffsA[0][3];
609 currentA = A + (predictionA >> 10);
611 p->buf[YADAPTCOEFFSA] = APESIGN(p->buf[YDELAYA ]);
612 p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]);
615 p->coeffsA[0][0] += p->buf[YADAPTCOEFFSA ] * sign;
616 p->coeffsA[0][1] += p->buf[YADAPTCOEFFSA - 1] * sign;
617 p->coeffsA[0][2] += p->buf[YADAPTCOEFFSA - 2] * sign;
618 p->coeffsA[0][3] += p->buf[YADAPTCOEFFSA - 3] * sign;
622 /* Have we filled the history buffer? */
623 if (p->buf == p->historybuffer + HISTORY_SIZE) {
624 memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t));
625 p->buf = p->historybuffer;
628 p->filterA[0] = currentA + ((p->filterA[0] * 31) >> 5);
629 *(decoded0++) = p->filterA[0];
632 p->lastA[0] = currentA;
635 static void do_init_filter(APEFilter *f, int16_t * buf, int order)
638 f->historybuffer = buf + order;
639 f->delay = f->historybuffer + order * 2;
640 f->adaptcoeffs = f->historybuffer + order;
642 memset(f->historybuffer, 0, (order * 2) * sizeof(int16_t));
643 memset(f->coeffs, 0, order * sizeof(int16_t));
647 static void init_filter(APEContext * ctx, APEFilter *f, int16_t * buf, int order)
649 do_init_filter(&f[0], buf, order);
650 do_init_filter(&f[1], buf + order * 3 + HISTORY_SIZE, order);
653 static void do_apply_filter(APEContext * ctx, int version, APEFilter *f, int32_t *data, int count, int order, int fracbits)
659 /* round fixedpoint scalar product */
660 res = ctx->dsp.scalarproduct_and_madd_int16(f->coeffs, f->delay - order, f->adaptcoeffs - order, order, APESIGN(*data));
661 res = (res + (1 << (fracbits - 1))) >> fracbits;
665 /* Update the output history */
666 *f->delay++ = av_clip_int16(res);
668 if (version < 3980) {
669 /* Version ??? to < 3.98 files (untested) */
670 f->adaptcoeffs[0] = (res == 0) ? 0 : ((res >> 28) & 8) - 4;
671 f->adaptcoeffs[-4] >>= 1;
672 f->adaptcoeffs[-8] >>= 1;
674 /* Version 3.98 and later files */
676 /* Update the adaption coefficients */
679 *f->adaptcoeffs = ((res & (1<<31)) - (1<<30)) >> (25 + (absres <= f->avg*3) + (absres <= f->avg*4/3));
683 f->avg += (absres - f->avg) / 16;
685 f->adaptcoeffs[-1] >>= 1;
686 f->adaptcoeffs[-2] >>= 1;
687 f->adaptcoeffs[-8] >>= 1;
692 /* Have we filled the history buffer? */
693 if (f->delay == f->historybuffer + HISTORY_SIZE + (order * 2)) {
694 memmove(f->historybuffer, f->delay - (order * 2),
695 (order * 2) * sizeof(int16_t));
696 f->delay = f->historybuffer + order * 2;
697 f->adaptcoeffs = f->historybuffer + order;
702 static void apply_filter(APEContext * ctx, APEFilter *f,
703 int32_t * data0, int32_t * data1,
704 int count, int order, int fracbits)
706 do_apply_filter(ctx, ctx->fileversion, &f[0], data0, count, order, fracbits);
708 do_apply_filter(ctx, ctx->fileversion, &f[1], data1, count, order, fracbits);
711 static void ape_apply_filters(APEContext * ctx, int32_t * decoded0,
712 int32_t * decoded1, int count)
716 for (i = 0; i < APE_FILTER_LEVELS; i++) {
717 if (!ape_filter_orders[ctx->fset][i])
719 apply_filter(ctx, ctx->filters[i], decoded0, decoded1, count, ape_filter_orders[ctx->fset][i], ape_filter_fracbits[ctx->fset][i]);
723 static void init_frame_decoder(APEContext * ctx)
726 init_entropy_decoder(ctx);
727 init_predictor_decoder(ctx);
729 for (i = 0; i < APE_FILTER_LEVELS; i++) {
730 if (!ape_filter_orders[ctx->fset][i])
732 init_filter(ctx, ctx->filters[i], ctx->filterbuf[i], ape_filter_orders[ctx->fset][i]);
736 static void ape_unpack_mono(APEContext * ctx, int count)
739 int32_t *decoded0 = ctx->decoded0;
740 int32_t *decoded1 = ctx->decoded1;
742 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
743 entropy_decode(ctx, count, 0);
744 /* We are pure silence, so we're done. */
745 av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence mono\n");
749 entropy_decode(ctx, count, 0);
750 ape_apply_filters(ctx, decoded0, NULL, count);
752 /* Now apply the predictor decoding */
753 predictor_decode_mono(ctx, count);
755 /* Pseudo-stereo - just copy left channel to right channel */
756 if (ctx->channels == 2) {
759 *(decoded1++) = *(decoded0++) = left;
764 static void ape_unpack_stereo(APEContext * ctx, int count)
767 int32_t *decoded0 = ctx->decoded0;
768 int32_t *decoded1 = ctx->decoded1;
770 if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) {
771 /* We are pure silence, so we're done. */
772 av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence stereo\n");
776 entropy_decode(ctx, count, 1);
777 ape_apply_filters(ctx, decoded0, decoded1, count);
779 /* Now apply the predictor decoding */
780 predictor_decode_stereo(ctx, count);
782 /* Decorrelate and scale to output depth */
784 left = *decoded1 - (*decoded0 / 2);
785 right = left + *decoded0;
787 *(decoded0++) = left;
788 *(decoded1++) = right;
792 static int ape_decode_frame(AVCodecContext * avctx,
793 void *data, int *data_size,
796 const uint8_t *buf = avpkt->data;
797 int buf_size = avpkt->size;
798 APEContext *s = avctx->priv_data;
799 int16_t *samples = data;
805 if (buf_size == 0 && !s->samples) {
810 /* should not happen but who knows */
811 if (BLOCKS_PER_LOOP * 2 * avctx->channels > *data_size) {
812 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);
817 s->data = av_realloc(s->data, (buf_size + 3) & ~3);
818 s->dsp.bswap_buf((uint32_t*)s->data, (const uint32_t*)buf, buf_size >> 2);
819 s->ptr = s->last_ptr = s->data;
820 s->data_end = s->data + buf_size;
822 nblocks = s->samples = bytestream_get_be32(&s->ptr);
823 n = bytestream_get_be32(&s->ptr);
825 av_log(avctx, AV_LOG_ERROR, "Incorrect offset passed\n");
831 s->currentframeblocks = nblocks;
833 if (s->samples <= 0) {
838 memset(s->decoded0, 0, sizeof(s->decoded0));
839 memset(s->decoded1, 0, sizeof(s->decoded1));
841 /* Initialize the frame decoder */
842 init_frame_decoder(s);
850 nblocks = s->samples;
851 blockstodecode = FFMIN(BLOCKS_PER_LOOP, nblocks);
855 if ((s->channels == 1) || (s->frameflags & APE_FRAMECODE_PSEUDO_STEREO))
856 ape_unpack_mono(s, blockstodecode);
858 ape_unpack_stereo(s, blockstodecode);
861 if(s->error || s->ptr > s->data_end){
863 av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n");
867 for (i = 0; i < blockstodecode; i++) {
868 *samples++ = s->decoded0[i];
870 *samples++ = s->decoded1[i];
873 s->samples -= blockstodecode;
875 *data_size = blockstodecode * 2 * s->channels;
876 bytes_used = s->samples ? s->ptr - s->last_ptr : buf_size;
877 s->last_ptr = s->ptr;
881 static void ape_flush(AVCodecContext *avctx)
883 APEContext *s = avctx->priv_data;
887 AVCodec ff_ape_decoder = {
896 .capabilities = CODEC_CAP_SUBFRAMES,
898 .long_name = NULL_IF_CONFIG_SMALL("Monkey's Audio"),