/* libFLAC - Free Lossless Audio Codec library * Copyright (C) 2000-2009 Josh Coalson * Copyright (C) 2011-2016 Xiph.Org Foundation * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of the Xiph.org Foundation nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifdef HAVE_CONFIG_H # include #endif #include #include #include "share/compat.h" #include "private/bitmath.h" #include "private/fixed.h" #include "private/macros.h" #include "FLAC/assert.h" #ifdef local_abs #undef local_abs #endif #define local_abs(x) ((unsigned)((x)<0? -(x) : (x))) #ifdef FLAC__INTEGER_ONLY_LIBRARY /* rbps stands for residual bits per sample * * (ln(2) * err) * rbps = log (-----------) * 2 ( n ) */ static FLAC__fixedpoint local__compute_rbps_integerized(FLAC__uint32 err, FLAC__uint32 n) { FLAC__uint32 rbps; unsigned bits; /* the number of bits required to represent a number */ int fracbits; /* the number of bits of rbps that comprise the fractional part */ FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint)); FLAC__ASSERT(err > 0); FLAC__ASSERT(n > 0); FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE); if(err <= n) return 0; /* * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1. * These allow us later to know we won't lose too much precision in the * fixed-point division (err< 0); bits = FLAC__bitmath_ilog2(err)+1; if(bits > 16) { err >>= (bits-16); fracbits -= (int)(bits-16); } rbps = (FLAC__uint32)err; /* Multiply by fixed-point version of ln(2), with 16 fractional bits */ rbps *= FLAC__FP_LN2; fracbits += 16; FLAC__ASSERT(fracbits >= 0); /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */ { const int f = fracbits & 3; if(f) { rbps >>= f; fracbits -= f; } } rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1)); if(rbps == 0) return 0; /* * The return value must have 16 fractional bits. Since the whole part * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits * must be >= -3, these assertion allows us to be able to shift rbps * left if necessary to get 16 fracbits without losing any bits of the * whole part of rbps. * * There is a slight chance due to accumulated error that the whole part * will require 6 bits, so we use 6 in the assertion. Really though as * long as it fits in 13 bits (32 - (16 - (-3))) we are fine. */ FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6); FLAC__ASSERT(fracbits >= -3); /* now shift the decimal point into place */ if(fracbits < 16) return rbps << (16-fracbits); else if(fracbits > 16) return rbps >> (fracbits-16); else return rbps; } static FLAC__fixedpoint local__compute_rbps_wide_integerized(FLAC__uint64 err, FLAC__uint32 n) { FLAC__uint32 rbps; unsigned bits; /* the number of bits required to represent a number */ int fracbits; /* the number of bits of rbps that comprise the fractional part */ FLAC__ASSERT(sizeof(rbps) == sizeof(FLAC__fixedpoint)); FLAC__ASSERT(err > 0); FLAC__ASSERT(n > 0); FLAC__ASSERT(n <= FLAC__MAX_BLOCK_SIZE); if(err <= n) return 0; /* * The above two things tell us 1) n fits in 16 bits; 2) err/n > 1. * These allow us later to know we won't lose too much precision in the * fixed-point division (err< 0); bits = FLAC__bitmath_ilog2_wide(err)+1; if(bits > 16) { err >>= (bits-16); fracbits -= (int)(bits-16); // defined, but cast to int to avoid ubsan assert. } rbps = (FLAC__uint32)err; /* Multiply by fixed-point version of ln(2), with 16 fractional bits */ rbps *= FLAC__FP_LN2; fracbits += 16; FLAC__ASSERT(fracbits >= 0); /* FLAC__fixedpoint_log2 requires fracbits%4 to be 0 */ { const int f = fracbits & 3; if(f) { rbps >>= f; fracbits -= f; } } rbps = FLAC__fixedpoint_log2(rbps, fracbits, (unsigned)(-1)); if(rbps == 0) return 0; /* * The return value must have 16 fractional bits. Since the whole part * of the base-2 log of a 32 bit number must fit in 5 bits, and fracbits * must be >= -3, these assertion allows us to be able to shift rbps * left if necessary to get 16 fracbits without losing any bits of the * whole part of rbps. * * There is a slight chance due to accumulated error that the whole part * will require 6 bits, so we use 6 in the assertion. Really though as * long as it fits in 13 bits (32 - (16 - (-3))) we are fine. */ FLAC__ASSERT((int)FLAC__bitmath_ilog2(rbps)+1 <= fracbits + 6); FLAC__ASSERT(fracbits >= -3); /* now shift the decimal point into place */ if(fracbits < 16) return rbps << (16-fracbits); else if(fracbits > 16) return rbps >> (fracbits-16); else return rbps; } #endif #ifndef FLAC__INTEGER_ONLY_LIBRARY unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #else unsigned FLAC__fixed_compute_best_predictor(const FLAC__int32 data[], unsigned data_len, FLAC__fixedpoint residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #endif { FLAC__int32 last_error_0 = data[-1]; FLAC__int32 last_error_1 = data[-1] - data[-2]; FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]); FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]); FLAC__int32 error, save; FLAC__uint32 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0; unsigned i, order; for(i = 0; i < data_len; i++) { error = data[i] ; total_error_0 += local_abs(error); save = error; error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error; error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error; error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error; error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save; } if(total_error_0 < flac_min(flac_min(flac_min(total_error_1, total_error_2), total_error_3), total_error_4)) order = 0; else if(total_error_1 < flac_min(flac_min(total_error_2, total_error_3), total_error_4)) order = 1; else if(total_error_2 < flac_min(total_error_3, total_error_4)) order = 2; else if(total_error_3 < total_error_4) order = 3; else order = 4; /* Estimate the expected number of bits per residual signal sample. */ /* 'total_error*' is linearly related to the variance of the residual */ /* signal, so we use it directly to compute E(|x|) */ FLAC__ASSERT(data_len > 0 || total_error_0 == 0); FLAC__ASSERT(data_len > 0 || total_error_1 == 0); FLAC__ASSERT(data_len > 0 || total_error_2 == 0); FLAC__ASSERT(data_len > 0 || total_error_3 == 0); FLAC__ASSERT(data_len > 0 || total_error_4 == 0); #ifndef FLAC__INTEGER_ONLY_LIBRARY residual_bits_per_sample[0] = (float)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[1] = (float)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[2] = (float)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[3] = (float)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[4] = (float)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double)data_len) / M_LN2 : 0.0); #else residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_integerized(total_error_0, data_len) : 0; residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_integerized(total_error_1, data_len) : 0; residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_integerized(total_error_2, data_len) : 0; residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_integerized(total_error_3, data_len) : 0; residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_integerized(total_error_4, data_len) : 0; #endif return order; } #ifndef FLAC__INTEGER_ONLY_LIBRARY unsigned FLAC__fixed_compute_best_predictor_wide(const FLAC__int32 data[], unsigned data_len, float residual_bits_per_sample[FLAC__MAX_FIXED_ORDER+1]) #else 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]) #endif { FLAC__int32 last_error_0 = data[-1]; FLAC__int32 last_error_1 = data[-1] - data[-2]; FLAC__int32 last_error_2 = last_error_1 - (data[-2] - data[-3]); FLAC__int32 last_error_3 = last_error_2 - (data[-2] - 2*data[-3] + data[-4]); FLAC__int32 error, save; /* total_error_* are 64-bits to avoid overflow when encoding * erratic signals when the bits-per-sample and blocksize are * large. */ FLAC__uint64 total_error_0 = 0, total_error_1 = 0, total_error_2 = 0, total_error_3 = 0, total_error_4 = 0; unsigned i, order; for(i = 0; i < data_len; i++) { error = data[i] ; total_error_0 += local_abs(error); save = error; error -= last_error_0; total_error_1 += local_abs(error); last_error_0 = save; save = error; error -= last_error_1; total_error_2 += local_abs(error); last_error_1 = save; save = error; error -= last_error_2; total_error_3 += local_abs(error); last_error_2 = save; save = error; error -= last_error_3; total_error_4 += local_abs(error); last_error_3 = save; } if(total_error_0 < flac_min(flac_min(flac_min(total_error_1, total_error_2), total_error_3), total_error_4)) order = 0; else if(total_error_1 < flac_min(flac_min(total_error_2, total_error_3), total_error_4)) order = 1; else if(total_error_2 < flac_min(total_error_3, total_error_4)) order = 2; else if(total_error_3 < total_error_4) order = 3; else order = 4; /* Estimate the expected number of bits per residual signal sample. */ /* 'total_error*' is linearly related to the variance of the residual */ /* signal, so we use it directly to compute E(|x|) */ FLAC__ASSERT(data_len > 0 || total_error_0 == 0); FLAC__ASSERT(data_len > 0 || total_error_1 == 0); FLAC__ASSERT(data_len > 0 || total_error_2 == 0); FLAC__ASSERT(data_len > 0 || total_error_3 == 0); FLAC__ASSERT(data_len > 0 || total_error_4 == 0); #ifndef FLAC__INTEGER_ONLY_LIBRARY residual_bits_per_sample[0] = (float)((total_error_0 > 0) ? log(M_LN2 * (double)total_error_0 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[1] = (float)((total_error_1 > 0) ? log(M_LN2 * (double)total_error_1 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[2] = (float)((total_error_2 > 0) ? log(M_LN2 * (double)total_error_2 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[3] = (float)((total_error_3 > 0) ? log(M_LN2 * (double)total_error_3 / (double)data_len) / M_LN2 : 0.0); residual_bits_per_sample[4] = (float)((total_error_4 > 0) ? log(M_LN2 * (double)total_error_4 / (double)data_len) / M_LN2 : 0.0); #else residual_bits_per_sample[0] = (total_error_0 > 0) ? local__compute_rbps_wide_integerized(total_error_0, data_len) : 0; residual_bits_per_sample[1] = (total_error_1 > 0) ? local__compute_rbps_wide_integerized(total_error_1, data_len) : 0; residual_bits_per_sample[2] = (total_error_2 > 0) ? local__compute_rbps_wide_integerized(total_error_2, data_len) : 0; residual_bits_per_sample[3] = (total_error_3 > 0) ? local__compute_rbps_wide_integerized(total_error_3, data_len) : 0; residual_bits_per_sample[4] = (total_error_4 > 0) ? local__compute_rbps_wide_integerized(total_error_4, data_len) : 0; #endif return order; } void FLAC__fixed_compute_residual(const FLAC__int32 data[], unsigned data_len, unsigned order, FLAC__int32 residual[]) { const int idata_len = (int)data_len; int i; switch(order) { case 0: FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0])); memcpy(residual, data, sizeof(residual[0])*data_len); break; case 1: for(i = 0; i < idata_len; i++) residual[i] = data[i] - data[i-1]; break; case 2: for(i = 0; i < idata_len; i++) residual[i] = data[i] - 2*data[i-1] + data[i-2]; break; case 3: for(i = 0; i < idata_len; i++) residual[i] = data[i] - 3*data[i-1] + 3*data[i-2] - data[i-3]; break; case 4: for(i = 0; i < idata_len; i++) residual[i] = data[i] - 4*data[i-1] + 6*data[i-2] - 4*data[i-3] + 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: FLAC__ASSERT(sizeof(residual[0]) == sizeof(data[0])); memcpy(data, residual, sizeof(residual[0])*data_len); 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++) data[i] = residual[i] + 2*data[i-1] - data[i-2]; break; case 3: for(i = 0; i < idata_len; i++) data[i] = residual[i] + 3*data[i-1] - 3*data[i-2] + data[i-3]; break; case 4: for(i = 0; i < idata_len; i++) data[i] = residual[i] + 4*data[i-1] - 6*data[i-2] + 4*data[i-3] - data[i-4]; break; default: FLAC__ASSERT(0); } }