/* * Monkey's Audio lossless audio decoder * Copyright (c) 2007 Benjamin Zores <ben@geexbox.org> * based upon libdemac from Dave Chapman. * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #define ALT_BITSTREAM_READER_LE #include "avcodec.h" #include "dsputil.h" #include "bitstream.h" #include "bytestream.h" /** * @file libavcodec/apedec.c * Monkey's Audio lossless audio decoder */ #define BLOCKS_PER_LOOP 4608 #define MAX_CHANNELS 2 #define MAX_BYTESPERSAMPLE 3 #define APE_FRAMECODE_MONO_SILENCE 1 #define APE_FRAMECODE_STEREO_SILENCE 3 #define APE_FRAMECODE_PSEUDO_STEREO 4 #define HISTORY_SIZE 512 #define PREDICTOR_ORDER 8 /** Total size of all predictor histories */ #define PREDICTOR_SIZE 50 #define YDELAYA (18 + PREDICTOR_ORDER*4) #define YDELAYB (18 + PREDICTOR_ORDER*3) #define XDELAYA (18 + PREDICTOR_ORDER*2) #define XDELAYB (18 + PREDICTOR_ORDER) #define YADAPTCOEFFSA 18 #define XADAPTCOEFFSA 14 #define YADAPTCOEFFSB 10 #define XADAPTCOEFFSB 5 /** * Possible compression levels * @{ */ enum APECompressionLevel { COMPRESSION_LEVEL_FAST = 1000, COMPRESSION_LEVEL_NORMAL = 2000, COMPRESSION_LEVEL_HIGH = 3000, COMPRESSION_LEVEL_EXTRA_HIGH = 4000, COMPRESSION_LEVEL_INSANE = 5000 }; /** @} */ #define APE_FILTER_LEVELS 3 /** Filter orders depending on compression level */ static const uint16_t ape_filter_orders[5][APE_FILTER_LEVELS] = { { 0, 0, 0 }, { 16, 0, 0 }, { 64, 0, 0 }, { 32, 256, 0 }, { 16, 256, 1280 } }; /** Filter fraction bits depending on compression level */ static const uint8_t ape_filter_fracbits[5][APE_FILTER_LEVELS] = { { 0, 0, 0 }, { 11, 0, 0 }, { 11, 0, 0 }, { 10, 13, 0 }, { 11, 13, 15 } }; /** Filters applied to the decoded data */ typedef struct APEFilter { int16_t *coeffs; ///< actual coefficients used in filtering int16_t *adaptcoeffs; ///< adaptive filter coefficients used for correcting of actual filter coefficients int16_t *historybuffer; ///< filter memory int16_t *delay; ///< filtered values int avg; } APEFilter; typedef struct APERice { uint32_t k; uint32_t ksum; } APERice; typedef struct APERangecoder { uint32_t low; ///< low end of interval uint32_t range; ///< length of interval uint32_t help; ///< bytes_to_follow resp. intermediate value unsigned int buffer; ///< buffer for input/output } APERangecoder; /** Filter histories */ typedef struct APEPredictor { int32_t *buf; int32_t lastA[2]; int32_t filterA[2]; int32_t filterB[2]; int32_t coeffsA[2][4]; ///< adaption coefficients int32_t coeffsB[2][5]; ///< adaption coefficients int32_t historybuffer[HISTORY_SIZE + PREDICTOR_SIZE]; } APEPredictor; /** Decoder context */ typedef struct APEContext { AVCodecContext *avctx; DSPContext dsp; int channels; int samples; ///< samples left to decode in current frame int fileversion; ///< codec version, very important in decoding process int compression_level; ///< compression levels int fset; ///< which filter set to use (calculated from compression level) int flags; ///< global decoder flags uint32_t CRC; ///< frame CRC int frameflags; ///< frame flags int currentframeblocks; ///< samples (per channel) in current frame int blocksdecoded; ///< count of decoded samples in current frame APEPredictor predictor; ///< predictor used for final reconstruction int32_t decoded0[BLOCKS_PER_LOOP]; ///< decoded data for the first channel int32_t decoded1[BLOCKS_PER_LOOP]; ///< decoded data for the second channel int16_t* filterbuf[APE_FILTER_LEVELS]; ///< filter memory APERangecoder rc; ///< rangecoder used to decode actual values APERice riceX; ///< rice code parameters for the second channel APERice riceY; ///< rice code parameters for the first channel APEFilter filters[APE_FILTER_LEVELS][2]; ///< filters used for reconstruction uint8_t *data; ///< current frame data uint8_t *data_end; ///< frame data end const uint8_t *ptr; ///< current position in frame data const uint8_t *last_ptr; ///< position where last 4608-sample block ended int error; } APEContext; // TODO: dsputilize static av_cold int ape_decode_init(AVCodecContext * avctx) { APEContext *s = avctx->priv_data; int i; if (avctx->extradata_size != 6) { av_log(avctx, AV_LOG_ERROR, "Incorrect extradata\n"); return -1; } if (avctx->bits_per_coded_sample != 16) { av_log(avctx, AV_LOG_ERROR, "Only 16-bit samples are supported\n"); return -1; } if (avctx->channels > 2) { av_log(avctx, AV_LOG_ERROR, "Only mono and stereo is supported\n"); return -1; } s->avctx = avctx; s->channels = avctx->channels; s->fileversion = AV_RL16(avctx->extradata); s->compression_level = AV_RL16(avctx->extradata + 2); s->flags = AV_RL16(avctx->extradata + 4); av_log(avctx, AV_LOG_DEBUG, "Compression Level: %d - Flags: %d\n", s->compression_level, s->flags); if (s->compression_level % 1000 || s->compression_level > COMPRESSION_LEVEL_INSANE) { av_log(avctx, AV_LOG_ERROR, "Incorrect compression level %d\n", s->compression_level); return -1; } s->fset = s->compression_level / 1000 - 1; for (i = 0; i < APE_FILTER_LEVELS; i++) { if (!ape_filter_orders[s->fset][i]) break; s->filterbuf[i] = av_malloc((ape_filter_orders[s->fset][i] * 3 + HISTORY_SIZE) * 4); } dsputil_init(&s->dsp, avctx); avctx->sample_fmt = SAMPLE_FMT_S16; avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO; return 0; } static av_cold int ape_decode_close(AVCodecContext * avctx) { APEContext *s = avctx->priv_data; int i; for (i = 0; i < APE_FILTER_LEVELS; i++) av_freep(&s->filterbuf[i]); return 0; } /** * @defgroup rangecoder APE range decoder * @{ */ #define CODE_BITS 32 #define TOP_VALUE ((unsigned int)1 << (CODE_BITS-1)) #define SHIFT_BITS (CODE_BITS - 9) #define EXTRA_BITS ((CODE_BITS-2) % 8 + 1) #define BOTTOM_VALUE (TOP_VALUE >> 8) /** Start the decoder */ static inline void range_start_decoding(APEContext * ctx) { ctx->rc.buffer = bytestream_get_byte(&ctx->ptr); ctx->rc.low = ctx->rc.buffer >> (8 - EXTRA_BITS); ctx->rc.range = (uint32_t) 1 << EXTRA_BITS; } /** Perform normalization */ static inline void range_dec_normalize(APEContext * ctx) { while (ctx->rc.range <= BOTTOM_VALUE) { ctx->rc.buffer <<= 8; if(ctx->ptr < ctx->data_end) ctx->rc.buffer += *ctx->ptr; ctx->ptr++; ctx->rc.low = (ctx->rc.low << 8) | ((ctx->rc.buffer >> 1) & 0xFF); ctx->rc.range <<= 8; } } /** * Calculate culmulative frequency for next symbol. Does NO update! * @param ctx decoder context * @param tot_f is the total frequency or (code_value)1<<shift * @return the culmulative frequency */ static inline int range_decode_culfreq(APEContext * ctx, int tot_f) { range_dec_normalize(ctx); ctx->rc.help = ctx->rc.range / tot_f; return ctx->rc.low / ctx->rc.help; } /** * Decode value with given size in bits * @param ctx decoder context * @param shift number of bits to decode */ static inline int range_decode_culshift(APEContext * ctx, int shift) { range_dec_normalize(ctx); ctx->rc.help = ctx->rc.range >> shift; return ctx->rc.low / ctx->rc.help; } /** * Update decoding state * @param ctx decoder context * @param sy_f the interval length (frequency of the symbol) * @param lt_f the lower end (frequency sum of < symbols) */ static inline void range_decode_update(APEContext * ctx, int sy_f, int lt_f) { ctx->rc.low -= ctx->rc.help * lt_f; ctx->rc.range = ctx->rc.help * sy_f; } /** Decode n bits (n <= 16) without modelling */ static inline int range_decode_bits(APEContext * ctx, int n) { int sym = range_decode_culshift(ctx, n); range_decode_update(ctx, 1, sym); return sym; } #define MODEL_ELEMENTS 64 /** * Fixed probabilities for symbols in Monkey Audio version 3.97 */ static const uint16_t counts_3970[22] = { 0, 14824, 28224, 39348, 47855, 53994, 58171, 60926, 62682, 63786, 64463, 64878, 65126, 65276, 65365, 65419, 65450, 65469, 65480, 65487, 65491, 65493, }; /** * Probability ranges for symbols in Monkey Audio version 3.97 */ static const uint16_t counts_diff_3970[21] = { 14824, 13400, 11124, 8507, 6139, 4177, 2755, 1756, 1104, 677, 415, 248, 150, 89, 54, 31, 19, 11, 7, 4, 2, }; /** * Fixed probabilities for symbols in Monkey Audio version 3.98 */ static const uint16_t counts_3980[22] = { 0, 19578, 36160, 48417, 56323, 60899, 63265, 64435, 64971, 65232, 65351, 65416, 65447, 65466, 65476, 65482, 65485, 65488, 65490, 65491, 65492, 65493, }; /** * Probability ranges for symbols in Monkey Audio version 3.98 */ static const uint16_t counts_diff_3980[21] = { 19578, 16582, 12257, 7906, 4576, 2366, 1170, 536, 261, 119, 65, 31, 19, 10, 6, 3, 3, 2, 1, 1, 1, }; /** * Decode symbol * @param ctx decoder context * @param counts probability range start position * @param counts_diff probability range widths */ static inline int range_get_symbol(APEContext * ctx, const uint16_t counts[], const uint16_t counts_diff[]) { int symbol, cf; cf = range_decode_culshift(ctx, 16); if(cf > 65492){ symbol= cf - 65535 + 63; range_decode_update(ctx, 1, cf); if(cf > 65535) ctx->error=1; return symbol; } /* figure out the symbol inefficiently; a binary search would be much better */ for (symbol = 0; counts[symbol + 1] <= cf; symbol++); range_decode_update(ctx, counts_diff[symbol], counts[symbol]); return symbol; } /** @} */ // group rangecoder static inline void update_rice(APERice *rice, int x) { int lim = rice->k ? (1 << (rice->k + 4)) : 0; rice->ksum += ((x + 1) / 2) - ((rice->ksum + 16) >> 5); if (rice->ksum < lim) rice->k--; else if (rice->ksum >= (1 << (rice->k + 5))) rice->k++; } static inline int ape_decode_value(APEContext * ctx, APERice *rice) { int x, overflow; if (ctx->fileversion < 3990) { int tmpk; overflow = range_get_symbol(ctx, counts_3970, counts_diff_3970); if (overflow == (MODEL_ELEMENTS - 1)) { tmpk = range_decode_bits(ctx, 5); overflow = 0; } else tmpk = (rice->k < 1) ? 0 : rice->k - 1; if (tmpk <= 16) x = range_decode_bits(ctx, tmpk); else { x = range_decode_bits(ctx, 16); x |= (range_decode_bits(ctx, tmpk - 16) << 16); } x += overflow << tmpk; } else { int base, pivot; pivot = rice->ksum >> 5; if (pivot == 0) pivot = 1; overflow = range_get_symbol(ctx, counts_3980, counts_diff_3980); if (overflow == (MODEL_ELEMENTS - 1)) { overflow = range_decode_bits(ctx, 16) << 16; overflow |= range_decode_bits(ctx, 16); } base = range_decode_culfreq(ctx, pivot); range_decode_update(ctx, 1, base); x = base + overflow * pivot; } update_rice(rice, x); /* Convert to signed */ if (x & 1) return (x >> 1) + 1; else return -(x >> 1); } static void entropy_decode(APEContext * ctx, int blockstodecode, int stereo) { int32_t *decoded0 = ctx->decoded0; int32_t *decoded1 = ctx->decoded1; ctx->blocksdecoded = blockstodecode; if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) { /* We are pure silence, just memset the output buffer. */ memset(decoded0, 0, blockstodecode * sizeof(int32_t)); memset(decoded1, 0, blockstodecode * sizeof(int32_t)); } else { while (blockstodecode--) { *decoded0++ = ape_decode_value(ctx, &ctx->riceY); if (stereo) *decoded1++ = ape_decode_value(ctx, &ctx->riceX); } } if (ctx->blocksdecoded == ctx->currentframeblocks) range_dec_normalize(ctx); /* normalize to use up all bytes */ } static void init_entropy_decoder(APEContext * ctx) { /* Read the CRC */ ctx->CRC = bytestream_get_be32(&ctx->ptr); /* Read the frame flags if they exist */ ctx->frameflags = 0; if ((ctx->fileversion > 3820) && (ctx->CRC & 0x80000000)) { ctx->CRC &= ~0x80000000; ctx->frameflags = bytestream_get_be32(&ctx->ptr); } /* Keep a count of the blocks decoded in this frame */ ctx->blocksdecoded = 0; /* Initialize the rice structs */ ctx->riceX.k = 10; ctx->riceX.ksum = (1 << ctx->riceX.k) * 16; ctx->riceY.k = 10; ctx->riceY.ksum = (1 << ctx->riceY.k) * 16; /* The first 8 bits of input are ignored. */ ctx->ptr++; range_start_decoding(ctx); } static const int32_t initial_coeffs[4] = { 360, 317, -109, 98 }; static void init_predictor_decoder(APEContext * ctx) { APEPredictor *p = &ctx->predictor; /* Zero the history buffers */ memset(p->historybuffer, 0, PREDICTOR_SIZE * sizeof(int32_t)); p->buf = p->historybuffer; /* Initialize and zero the coefficients */ memcpy(p->coeffsA[0], initial_coeffs, sizeof(initial_coeffs)); memcpy(p->coeffsA[1], initial_coeffs, sizeof(initial_coeffs)); memset(p->coeffsB, 0, sizeof(p->coeffsB)); p->filterA[0] = p->filterA[1] = 0; p->filterB[0] = p->filterB[1] = 0; p->lastA[0] = p->lastA[1] = 0; } /** Get inverse sign of integer (-1 for positive, 1 for negative and 0 for zero) */ static inline int APESIGN(int32_t x) { return (x < 0) - (x > 0); } 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) { int32_t predictionA, predictionB; p->buf[delayA] = p->lastA[filter]; p->buf[adaptA] = APESIGN(p->buf[delayA]); p->buf[delayA - 1] = p->buf[delayA] - p->buf[delayA - 1]; p->buf[adaptA - 1] = APESIGN(p->buf[delayA - 1]); predictionA = p->buf[delayA ] * p->coeffsA[filter][0] + p->buf[delayA - 1] * p->coeffsA[filter][1] + p->buf[delayA - 2] * p->coeffsA[filter][2] + p->buf[delayA - 3] * p->coeffsA[filter][3]; /* Apply a scaled first-order filter compression */ p->buf[delayB] = p->filterA[filter ^ 1] - ((p->filterB[filter] * 31) >> 5); p->buf[adaptB] = APESIGN(p->buf[delayB]); p->buf[delayB - 1] = p->buf[delayB] - p->buf[delayB - 1]; p->buf[adaptB - 1] = APESIGN(p->buf[delayB - 1]); p->filterB[filter] = p->filterA[filter ^ 1]; predictionB = p->buf[delayB ] * p->coeffsB[filter][0] + p->buf[delayB - 1] * p->coeffsB[filter][1] + p->buf[delayB - 2] * p->coeffsB[filter][2] + p->buf[delayB - 3] * p->coeffsB[filter][3] + p->buf[delayB - 4] * p->coeffsB[filter][4]; p->lastA[filter] = decoded + ((predictionA + (predictionB >> 1)) >> 10); p->filterA[filter] = p->lastA[filter] + ((p->filterA[filter] * 31) >> 5); if (!decoded) // no need updating filter coefficients return p->filterA[filter]; if (decoded > 0) { p->coeffsA[filter][0] -= p->buf[adaptA ]; p->coeffsA[filter][1] -= p->buf[adaptA - 1]; p->coeffsA[filter][2] -= p->buf[adaptA - 2]; p->coeffsA[filter][3] -= p->buf[adaptA - 3]; p->coeffsB[filter][0] -= p->buf[adaptB ]; p->coeffsB[filter][1] -= p->buf[adaptB - 1]; p->coeffsB[filter][2] -= p->buf[adaptB - 2]; p->coeffsB[filter][3] -= p->buf[adaptB - 3]; p->coeffsB[filter][4] -= p->buf[adaptB - 4]; } else { p->coeffsA[filter][0] += p->buf[adaptA ]; p->coeffsA[filter][1] += p->buf[adaptA - 1]; p->coeffsA[filter][2] += p->buf[adaptA - 2]; p->coeffsA[filter][3] += p->buf[adaptA - 3]; p->coeffsB[filter][0] += p->buf[adaptB ]; p->coeffsB[filter][1] += p->buf[adaptB - 1]; p->coeffsB[filter][2] += p->buf[adaptB - 2]; p->coeffsB[filter][3] += p->buf[adaptB - 3]; p->coeffsB[filter][4] += p->buf[adaptB - 4]; } return p->filterA[filter]; } static void predictor_decode_stereo(APEContext * ctx, int count) { int32_t predictionA, predictionB; APEPredictor *p = &ctx->predictor; int32_t *decoded0 = ctx->decoded0; int32_t *decoded1 = ctx->decoded1; while (count--) { /* Predictor Y */ predictionA = predictor_update_filter(p, *decoded0, 0, YDELAYA, YDELAYB, YADAPTCOEFFSA, YADAPTCOEFFSB); predictionB = predictor_update_filter(p, *decoded1, 1, XDELAYA, XDELAYB, XADAPTCOEFFSA, XADAPTCOEFFSB); *(decoded0++) = predictionA; *(decoded1++) = predictionB; /* Combined */ p->buf++; /* Have we filled the history buffer? */ if (p->buf == p->historybuffer + HISTORY_SIZE) { memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t)); p->buf = p->historybuffer; } } } static void predictor_decode_mono(APEContext * ctx, int count) { APEPredictor *p = &ctx->predictor; int32_t *decoded0 = ctx->decoded0; int32_t predictionA, currentA, A; currentA = p->lastA[0]; while (count--) { A = *decoded0; p->buf[YDELAYA] = currentA; p->buf[YDELAYA - 1] = p->buf[YDELAYA] - p->buf[YDELAYA - 1]; predictionA = p->buf[YDELAYA ] * p->coeffsA[0][0] + p->buf[YDELAYA - 1] * p->coeffsA[0][1] + p->buf[YDELAYA - 2] * p->coeffsA[0][2] + p->buf[YDELAYA - 3] * p->coeffsA[0][3]; currentA = A + (predictionA >> 10); p->buf[YADAPTCOEFFSA] = APESIGN(p->buf[YDELAYA ]); p->buf[YADAPTCOEFFSA - 1] = APESIGN(p->buf[YDELAYA - 1]); if (A > 0) { p->coeffsA[0][0] -= p->buf[YADAPTCOEFFSA ]; p->coeffsA[0][1] -= p->buf[YADAPTCOEFFSA - 1]; p->coeffsA[0][2] -= p->buf[YADAPTCOEFFSA - 2]; p->coeffsA[0][3] -= p->buf[YADAPTCOEFFSA - 3]; } else if (A < 0) { p->coeffsA[0][0] += p->buf[YADAPTCOEFFSA ]; p->coeffsA[0][1] += p->buf[YADAPTCOEFFSA - 1]; p->coeffsA[0][2] += p->buf[YADAPTCOEFFSA - 2]; p->coeffsA[0][3] += p->buf[YADAPTCOEFFSA - 3]; } p->buf++; /* Have we filled the history buffer? */ if (p->buf == p->historybuffer + HISTORY_SIZE) { memmove(p->historybuffer, p->buf, PREDICTOR_SIZE * sizeof(int32_t)); p->buf = p->historybuffer; } p->filterA[0] = currentA + ((p->filterA[0] * 31) >> 5); *(decoded0++) = p->filterA[0]; } p->lastA[0] = currentA; } static void do_init_filter(APEFilter *f, int16_t * buf, int order) { f->coeffs = buf; f->historybuffer = buf + order; f->delay = f->historybuffer + order * 2; f->adaptcoeffs = f->historybuffer + order; memset(f->historybuffer, 0, (order * 2) * sizeof(int16_t)); memset(f->coeffs, 0, order * sizeof(int16_t)); f->avg = 0; } static void init_filter(APEContext * ctx, APEFilter *f, int16_t * buf, int order) { do_init_filter(&f[0], buf, order); do_init_filter(&f[1], buf + order * 3 + HISTORY_SIZE, order); } static inline void do_apply_filter(APEContext * ctx, int version, APEFilter *f, int32_t *data, int count, int order, int fracbits) { int res; int absres; while (count--) { /* round fixedpoint scalar product */ res = (ctx->dsp.scalarproduct_int16(f->delay - order, f->coeffs, order, 0) + (1 << (fracbits - 1))) >> fracbits; if (*data < 0) ctx->dsp.add_int16(f->coeffs, f->adaptcoeffs - order, order); else if (*data > 0) ctx->dsp.sub_int16(f->coeffs, f->adaptcoeffs - order, order); res += *data; *data++ = res; /* Update the output history */ *f->delay++ = av_clip_int16(res); if (version < 3980) { /* Version ??? to < 3.98 files (untested) */ f->adaptcoeffs[0] = (res == 0) ? 0 : ((res >> 28) & 8) - 4; f->adaptcoeffs[-4] >>= 1; f->adaptcoeffs[-8] >>= 1; } else { /* Version 3.98 and later files */ /* Update the adaption coefficients */ absres = (res < 0 ? -res : res); if (absres > (f->avg * 3)) *f->adaptcoeffs = ((res >> 25) & 64) - 32; else if (absres > (f->avg * 4) / 3) *f->adaptcoeffs = ((res >> 26) & 32) - 16; else if (absres > 0) *f->adaptcoeffs = ((res >> 27) & 16) - 8; else *f->adaptcoeffs = 0; f->avg += (absres - f->avg) / 16; f->adaptcoeffs[-1] >>= 1; f->adaptcoeffs[-2] >>= 1; f->adaptcoeffs[-8] >>= 1; } f->adaptcoeffs++; /* Have we filled the history buffer? */ if (f->delay == f->historybuffer + HISTORY_SIZE + (order * 2)) { memmove(f->historybuffer, f->delay - (order * 2), (order * 2) * sizeof(int16_t)); f->delay = f->historybuffer + order * 2; f->adaptcoeffs = f->historybuffer + order; } } } static void apply_filter(APEContext * ctx, APEFilter *f, int32_t * data0, int32_t * data1, int count, int order, int fracbits) { do_apply_filter(ctx, ctx->fileversion, &f[0], data0, count, order, fracbits); if (data1) do_apply_filter(ctx, ctx->fileversion, &f[1], data1, count, order, fracbits); } static void ape_apply_filters(APEContext * ctx, int32_t * decoded0, int32_t * decoded1, int count) { int i; for (i = 0; i < APE_FILTER_LEVELS; i++) { if (!ape_filter_orders[ctx->fset][i]) break; apply_filter(ctx, ctx->filters[i], decoded0, decoded1, count, ape_filter_orders[ctx->fset][i], ape_filter_fracbits[ctx->fset][i]); } } static void init_frame_decoder(APEContext * ctx) { int i; init_entropy_decoder(ctx); init_predictor_decoder(ctx); for (i = 0; i < APE_FILTER_LEVELS; i++) { if (!ape_filter_orders[ctx->fset][i]) break; init_filter(ctx, ctx->filters[i], ctx->filterbuf[i], ape_filter_orders[ctx->fset][i]); } } static void ape_unpack_mono(APEContext * ctx, int count) { int32_t left; int32_t *decoded0 = ctx->decoded0; int32_t *decoded1 = ctx->decoded1; if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) { entropy_decode(ctx, count, 0); /* We are pure silence, so we're done. */ av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence mono\n"); return; } entropy_decode(ctx, count, 0); ape_apply_filters(ctx, decoded0, NULL, count); /* Now apply the predictor decoding */ predictor_decode_mono(ctx, count); /* Pseudo-stereo - just copy left channel to right channel */ if (ctx->channels == 2) { while (count--) { left = *decoded0; *(decoded1++) = *(decoded0++) = left; } } } static void ape_unpack_stereo(APEContext * ctx, int count) { int32_t left, right; int32_t *decoded0 = ctx->decoded0; int32_t *decoded1 = ctx->decoded1; if (ctx->frameflags & APE_FRAMECODE_STEREO_SILENCE) { /* We are pure silence, so we're done. */ av_log(ctx->avctx, AV_LOG_DEBUG, "pure silence stereo\n"); return; } entropy_decode(ctx, count, 1); ape_apply_filters(ctx, decoded0, decoded1, count); /* Now apply the predictor decoding */ predictor_decode_stereo(ctx, count); /* Decorrelate and scale to output depth */ while (count--) { left = *decoded1 - (*decoded0 / 2); right = left + *decoded0; *(decoded0++) = left; *(decoded1++) = right; } } static int ape_decode_frame(AVCodecContext * avctx, void *data, int *data_size, const uint8_t * buf, int buf_size) { APEContext *s = avctx->priv_data; int16_t *samples = data; int nblocks; int i, n; int blockstodecode; int bytes_used; if (buf_size == 0 && !s->samples) { *data_size = 0; return 0; } /* should not happen but who knows */ if (BLOCKS_PER_LOOP * 2 * avctx->channels > *data_size) { 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); return -1; } if(!s->samples){ s->data = av_realloc(s->data, (buf_size + 3) & ~3); s->dsp.bswap_buf((uint32_t*)s->data, (const uint32_t*)buf, buf_size >> 2); s->ptr = s->last_ptr = s->data; s->data_end = s->data + buf_size; nblocks = s->samples = bytestream_get_be32(&s->ptr); n = bytestream_get_be32(&s->ptr); if(n < 0 || n > 3){ av_log(avctx, AV_LOG_ERROR, "Incorrect offset passed\n"); s->data = NULL; return -1; } s->ptr += n; s->currentframeblocks = nblocks; buf += 4; if (s->samples <= 0) { *data_size = 0; return buf_size; } memset(s->decoded0, 0, sizeof(s->decoded0)); memset(s->decoded1, 0, sizeof(s->decoded1)); /* Initialize the frame decoder */ init_frame_decoder(s); } if (!s->data) { *data_size = 0; return buf_size; } nblocks = s->samples; blockstodecode = FFMIN(BLOCKS_PER_LOOP, nblocks); s->error=0; if ((s->channels == 1) || (s->frameflags & APE_FRAMECODE_PSEUDO_STEREO)) ape_unpack_mono(s, blockstodecode); else ape_unpack_stereo(s, blockstodecode); if(s->error || s->ptr > s->data_end){ s->samples=0; av_log(avctx, AV_LOG_ERROR, "Error decoding frame\n"); return -1; } for (i = 0; i < blockstodecode; i++) { *samples++ = s->decoded0[i]; if(s->channels == 2) *samples++ = s->decoded1[i]; } s->samples -= blockstodecode; *data_size = blockstodecode * 2 * s->channels; bytes_used = s->samples ? s->ptr - s->last_ptr : buf_size; s->last_ptr = s->ptr; return bytes_used; } AVCodec ape_decoder = { "ape", CODEC_TYPE_AUDIO, CODEC_ID_APE, sizeof(APEContext), ape_decode_init, NULL, ape_decode_close, ape_decode_frame, .long_name = NULL_IF_CONFIG_SMALL("Monkey's Audio"), };