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FFmpeg/libavcodec/apedec.c
Stefano Sabatini 9106a698e7 Rename bitstream.h to get_bits.h. 
Originally committed as revision 18494 to svn://svn.ffmpeg.org/ffmpeg/trunk
2009-04-13 16:20:26 +00:00

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/*
* 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 "get_bits.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,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->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"),
};
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