aa97e4d498
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@5983 a1c6a512-1295-4272-9138-f99709370657
422 lines
16 KiB
C
422 lines
16 KiB
C
/* libFLAC - Free Lossless Audio Codec library
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* Copyright (C) 2000,2001,2002,2003,2004,2005 Josh Coalson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of the Xiph.org Foundation nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <math.h>
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#include "private/bitmath.h"
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#include "private/fixed.h"
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#include "FLAC/assert.h"
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#ifndef M_LN2
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/* math.h in VC++ doesn't seem to have this (how Microsoft is that?) */
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#define M_LN2 0.69314718055994530942
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#endif
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#ifdef min
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#undef min
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#endif
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#define min(x,y) ((x) < (y)? (x) : (y))
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#ifdef local_abs
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#undef local_abs
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#endif
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#define local_abs(x) ((unsigned)((x)<0? -(x) : (x)))
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#ifdef FLAC__INTEGER_ONLY_LIBRARY
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/* rbps stands for residual bits per sample
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*
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* (ln(2) * err)
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* rbps = log (-----------)
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* 2 ( n )
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*/
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static FLAC__fixedpoint local__compute_rbps_integerized(FLAC__uint32 err, FLAC__uint32 n)
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{
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FLAC__uint32 rbps;
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unsigned bits; /* the number of bits required to represent a number */
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int fracbits; /* the number of bits of rbps that comprise the fractional part */
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FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint));
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FLAC__ASSERT(err > 0);
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FLAC__ASSERT(n > 0);
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FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE);
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if(err <= n)
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return 0;
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/*
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* The above two things tell us 1) n fits in 16 bits; 2) err/n > 1.
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* These allow us later to know we won't lose too much precision in the
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* fixed-point division (err<<fracbits)/n.
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*/
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fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2(err)+1);
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err <<= fracbits;
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err /= n;
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/* err now holds err/n with fracbits fractional bits */
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/*
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* Whittle err down to 16 bits max. 16 significant bits is enough for
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* our purposes.
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*/
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FLAC__ASSERT(err > 0);
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bits = FLAC__bitmath_ilog2(err)+1;
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if(bits > 16) {
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err >>= (bits-16);
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fracbits -= (bits-16);
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}
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rbps = (FLAC__uint32)err;
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/* Multiply by fixed-point version of ln(2), with 16 fractional bits */
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rbps *= FLAC__FP_LN2;
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fracbits += 16;
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FLAC__ASSERT(fracbits >= 0);
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/* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */
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{
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const int f = fracbits & 3;
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if(f) {
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rbps >>= f;
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fracbits -= f;
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}
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}
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rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1));
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if(rbps == 0)
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return 0;
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/*
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* The return value must have 16 fractional bits. Since the whole part
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* of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits
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* must be >= -3, these assertion allows us to be able to shift rbps
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* left if necessary to get 16 fracbits without losing any bits of the
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* whole part of rbps.
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*
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* There is a slight chance due to accumulated error that the whole part
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* will require 6 bits, so we use 6 in the assertion. Really though as
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* long as it fits in 13 bits (32 - (16 - (-3))) we are fine.
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*/
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FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6);
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FLAC__ASSERT(fracbits >= -3);
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/* now shift the decimal point into place */
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if(fracbits < 16)
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return rbps << (16-fracbits);
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else if(fracbits > 16)
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return rbps >> (fracbits-16);
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else
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return rbps;
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}
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static FLAC__fixedpoint local__compute_rbps_wide_integerized(FLAC__uint64 err, FLAC__uint32 n)
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{
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FLAC__uint32 rbps;
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unsigned bits; /* the number of bits required to represent a number */
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int fracbits; /* the number of bits of rbps that comprise the fractional part */
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FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint));
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FLAC__ASSERT(err > 0);
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FLAC__ASSERT(n > 0);
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FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE);
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if(err <= n)
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return 0;
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/*
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* The above two things tell us 1) n fits in 16 bits; 2) err/n > 1.
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* These allow us later to know we won't lose too much precision in the
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* fixed-point division (err<<fracbits)/n.
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*/
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fracbits = (8*sizeof(err)) - (FLAC__bitmath_ilog2_wide(err)+1);
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err <<= fracbits;
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err /= n;
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/* err now holds err/n with fracbits fractional bits */
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/*
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* Whittle err down to 16 bits max. 16 significant bits is enough for
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* our purposes.
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*/
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FLAC__ASSERT(err > 0);
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bits = FLAC__bitmath_ilog2_wide(err)+1;
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if(bits > 16) {
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err >>= (bits-16);
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fracbits -= (bits-16);
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}
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rbps = (FLAC__uint32)err;
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/* Multiply by fixed-point version of ln(2), with 16 fractional bits */
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rbps *= FLAC__FP_LN2;
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fracbits += 16;
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FLAC__ASSERT(fracbits >= 0);
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/* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */
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{
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const int f = fracbits & 3;
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if(f) {
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rbps >>= f;
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fracbits -= f;
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}
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}
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rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1));
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if(rbps == 0)
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return 0;
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/*
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* The return value must have 16 fractional bits. Since the whole part
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* of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits
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* must be >= -3, these assertion allows us to be able to shift rbps
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* left if necessary to get 16 fracbits without losing any bits of the
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* whole part of rbps.
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*
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* There is a slight chance due to accumulated error that the whole part
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* will require 6 bits, so we use 6 in the assertion. Really though as
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* long as it fits in 13 bits (32 - (16 - (-3))) we are fine.
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*/
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FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6);
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FLAC__ASSERT(fracbits >= -3);
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/* now shift the decimal point into place */
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if(fracbits < 16)
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return rbps << (16-fracbits);
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else if(fracbits > 16)
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return rbps >> (fracbits-16);
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else
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return rbps;
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}
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#endif
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#ifndef FLAC__INTEGER_ONLY_LIBRARY
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unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
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#else
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unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
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#endif
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{
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FLAC__int32 last_error_0 = data[-1];
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FLAC__int32 last_error_1 = data[-1] - data[-2];
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FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
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FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
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FLAC__int32 error, save;
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FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
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unsigned i, order;
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for(i = 0; i < data_len; i++) {
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error = data[i] ; total_error_0 += local_abs(error); save = error;
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error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
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error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
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error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
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error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
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}
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if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
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order = 0;
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else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
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order = 1;
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else if(total_error_2 < min(total_error_3, total_error_4))
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order = 2;
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else if(total_error_3 < total_error_4)
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order = 3;
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else
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order = 4;
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/* Estimate the expected number of bits per residual signal sample. */
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/* 'total_error*' is linearly related to the variance of the residual */
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/* signal, so we use it directly to compute E(|x|) */
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FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
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#ifndef FLAC__INTEGER_ONLY_LIBRARY
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residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
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#else
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residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_integerized(total_error_0, data_len) : 0;
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residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_integerized(total_error_1, data_len) : 0;
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residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_integerized(total_error_2, data_len) : 0;
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residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_integerized(total_error_3, data_len) : 0;
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residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_integerized(total_error_4, data_len) : 0;
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#endif
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return order;
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}
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#ifndef FLAC__INTEGER_ONLY_LIBRARY
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unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
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#else
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unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1])
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#endif
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{
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FLAC__int32 last_error_0 = data[-1];
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FLAC__int32 last_error_1 = data[-1] - data[-2];
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FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]);
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FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]);
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FLAC__int32 error, save;
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/* total_error_* are 64-bits to avoid overflow when encoding
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* erratic signals when the bits-per-sample and blocksize are
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* large.
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*/
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FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0;
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unsigned i, order;
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for(i = 0; i < data_len; i++) {
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error = data[i] ; total_error_0 += local_abs(error); save = error;
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error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error;
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error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error;
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error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error;
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error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save;
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}
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if(total_error_0 < min(min(min(total_error_1, total_error_2), total_error_3), total_error_4))
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order = 0;
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else if(total_error_1 < min(min(total_error_2, total_error_3), total_error_4))
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order = 1;
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else if(total_error_2 < min(total_error_3, total_error_4))
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order = 2;
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else if(total_error_3 < total_error_4)
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order = 3;
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else
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order = 4;
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/* Estimate the expected number of bits per residual signal sample. */
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/* 'total_error*' is linearly related to the variance of the residual */
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/* signal, so we use it directly to compute E(|x|) */
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FLAC__ASSERT(data_len > 0 || total_error_0 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_1 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_2 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_3 == 0);
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FLAC__ASSERT(data_len > 0 || total_error_4 == 0);
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#ifndef FLAC__INTEGER_ONLY_LIBRARY
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#if defined _MSC_VER || defined __MINGW32__
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/* with MSVC you have to spoon feed it the casting */
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residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)(FLAC__int64)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
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#else
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residual_bits_per_sample[0] = (FLAC__float)((total_error_0 > 0) ? log(M_LN2 * (FLAC__double)total_error_0 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[1] = (FLAC__float)((total_error_1 > 0) ? log(M_LN2 * (FLAC__double)total_error_1 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[2] = (FLAC__float)((total_error_2 > 0) ? log(M_LN2 * (FLAC__double)total_error_2 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[3] = (FLAC__float)((total_error_3 > 0) ? log(M_LN2 * (FLAC__double)total_error_3 / (FLAC__double)data_len) / M_LN2 : 0.0);
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residual_bits_per_sample[4] = (FLAC__float)((total_error_4 > 0) ? log(M_LN2 * (FLAC__double)total_error_4 / (FLAC__double)data_len) / M_LN2 : 0.0);
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#endif
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#else
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residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_wide_integerized(total_error_0, data_len) : 0;
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residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_wide_integerized(total_error_1, data_len) : 0;
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residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_wide_integerized(total_error_2, data_len) : 0;
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residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_wide_integerized(total_error_3, data_len) : 0;
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residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_wide_integerized(total_error_4, data_len) : 0;
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#endif
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return order;
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}
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void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[])
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{
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const int idata_len = (int)data_len;
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int i;
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switch(order) {
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case 0:
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for(i = 0; i < idata_len; i++) {
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residual[i] = data[i];
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}
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break;
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case 1:
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for(i = 0; i < idata_len; i++) {
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residual[i] = data[i] - data[i-1];
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}
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break;
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case 2:
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for(i = 0; i < idata_len; i++) {
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/* == data[i] - 2*data[i-1] + data[i-2] */
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residual[i] = data[i] - (data[i-1] << 1) + data[i-2];
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}
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break;
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case 3:
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for(i = 0; i < idata_len; i++) {
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/* == data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3] */
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residual[i] = data[i] - (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) - data[i-3];
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}
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break;
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case 4:
|
|
for(i = 0; i < idata_len; i++) {
|
|
/* == data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4] */
|
|
residual[i] = data[i] - ((data[i-1]+data[i-3])<<2) + ((data[i-2]<<2) + (data[i-2]<<1)) + data[i-4];
|
|
}
|
|
break;
|
|
default:
|
|
FLAC__ASSERT(0);
|
|
}
|
|
}
|
|
|
|
void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[])
|
|
{
|
|
int i, idata_len = (int)data_len;
|
|
|
|
switch(order) {
|
|
case 0:
|
|
for(i = 0; i < idata_len; i++) {
|
|
data[i] = residual[i];
|
|
}
|
|
break;
|
|
case 1:
|
|
for(i = 0; i < idata_len; i++) {
|
|
data[i] = residual[i] + data[i-1];
|
|
}
|
|
break;
|
|
case 2:
|
|
for(i = 0; i < idata_len; i++) {
|
|
/* == residual[i] + 2*data[i-1] - data[i-2] */
|
|
data[i] = residual[i] + (data[i-1]<<1) - data[i-2];
|
|
}
|
|
break;
|
|
case 3:
|
|
for(i = 0; i < idata_len; i++) {
|
|
/* residual[i] + 3*data[i-1] - 3*data[i-2]) + data[i-3] */
|
|
data[i] = residual[i] + (((data[i-1]-data[i-2])<<1) + (data[i-1]-data[i-2])) + data[i-3];
|
|
}
|
|
break;
|
|
case 4:
|
|
for(i = 0; i < idata_len; i++) {
|
|
/* == residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4] */
|
|
data[i] = residual[i] + ((data[i-1]+data[i-3])<<2) - ((data[i-2]<<2) + (data[i-2]<<1)) - data[i-4];
|
|
}
|
|
break;
|
|
default:
|
|
FLAC__ASSERT(0);
|
|
}
|
|
}
|