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395 lines
15 KiB
395 lines
15 KiB
/* libFLAC - Free Lossless Audio Codec library |
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* Copyright (C) 2000-2009 Josh Coalson |
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* Copyright (C) 2011-2016 Xiph.Org Foundation |
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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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#ifdef HAVE_CONFIG_H |
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# include <config.h> |
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#endif |
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#include <math.h> |
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#include <string.h> |
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#include "share/compat.h" |
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#include "private/bitmath.h" |
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#include "private/fixed.h" |
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#include "private/macros.h" |
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#include "FLAC/assert.h" |
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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 -= (int)(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 -= (int)(bits-16); // defined, but cast to int to avoid ubsan assert. |
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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, 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 < flac_min(flac_min(flac_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 < flac_min(flac_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 < flac_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] = (float)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[1] = (float)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[2] = (float)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[3] = (float)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[4] = (float)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (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, 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 < flac_min(flac_min(flac_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 < flac_min(flac_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 < flac_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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|
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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] = (float)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[1] = (float)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[2] = (float)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[3] = (float)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0); |
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residual_bits_per_sample[4] = (float)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (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_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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FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0])); |
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memcpy(residual, data, sizeof(residual[0])*data_len); |
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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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break; |
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case 2: |
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for(i = 0; i < idata_len; i++) |
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residual[i] = data[i] - 2*data[i-1] + data[i-2]; |
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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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residual[i] = data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3]; |
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break; |
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case 4: |
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for(i = 0; i < idata_len; i++) |
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residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + data[i-4]; |
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break; |
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default: |
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FLAC__ASSERT(0); |
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} |
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} |
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void FLAC__fixed_restore_signal(const FLAC__int32 residual[], unsigned data_len, unsigned order, FLAC__int32 data[]) |
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{ |
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int i, idata_len = (int)data_len; |
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switch(order) { |
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case 0: |
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FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0])); |
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memcpy(data, residual, sizeof(residual[0])*data_len); |
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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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data[i] = residual[i] + data[i-1]; |
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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] = residual[i] + 2*data[i-1] - data[i-2]; |
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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] = residual[i] + 3*data[i-1] - 3*data[i-2] + data[i-3]; |
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break; |
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case 4: |
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for(i = 0; i < idata_len; i++) |
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data[i] = residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4]; |
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break; |
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default: |
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FLAC__ASSERT(0); |
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} |
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}
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