1 /* libFLAC - Free Lossless Audio Codec library
2 * Copyright (C) 2000,2001,2002,2003,2004 Josh Coalson
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
8 * - Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * - Neither the name of the Xiph.org Foundation nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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32 #ifndef FLAC__PRIVATE__LPC_H
33 #define FLAC__PRIVATE__LPC_H
35 #include "FLAC/format.h"
42 * FLAC__lpc_compute_autocorrelation()
43 * --------------------------------------------------------------------
44 * Compute the autocorrelation for lags between 0 and lag-1.
45 * Assumes data[] outside of [0,data_len-1] == 0.
46 * Asserts that lag > 0.
48 * IN data[0,data_len-1]
50 * IN 0 < lag <= data_len
53 void FLAC__lpc_compute_autocorrelation(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[]);
55 # ifdef FLAC__CPU_IA32
56 # ifdef FLAC__HAS_NASM
57 void FLAC__lpc_compute_autocorrelation_asm_ia32(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[]);
58 void FLAC__lpc_compute_autocorrelation_asm_ia32_sse_lag_4(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[]);
59 void FLAC__lpc_compute_autocorrelation_asm_ia32_sse_lag_8(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[]);
60 void FLAC__lpc_compute_autocorrelation_asm_ia32_sse_lag_12(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[]);
61 void FLAC__lpc_compute_autocorrelation_asm_ia32_3dnow(const FLAC__real data[], unsigned data_len, unsigned lag, FLAC__real autoc[]);
67 * FLAC__lpc_compute_lp_coefficients()
68 * --------------------------------------------------------------------
69 * Computes LP coefficients for orders 1..max_order.
70 * Do not call if autoc[0] == 0.0. This means the signal is zero
71 * and there is no point in calculating a predictor.
73 * IN autoc[0,max_order] autocorrelation values
74 * IN 0 < max_order <= FLAC__MAX_LPC_ORDER max LP order to compute
75 * OUT lp_coeff[0,max_order-1][0,max_order-1] LP coefficients for each order
77 * *** lp_coeff[0,max_order-1][max_order,FLAC__MAX_LPC_ORDER-1] are untouched
78 * OUT error[0,max_order-1] error for each order
80 * Example: if max_order is 9, the LP coefficients for order 9 will be
81 * in lp_coeff[8][0,8], the LP coefficients for order 8 will be
82 * in lp_coeff[7][0,7], etc.
84 void FLAC__lpc_compute_lp_coefficients(const FLAC__real autoc[], unsigned max_order, FLAC__real lp_coeff[][FLAC__MAX_LPC_ORDER], FLAC__real error[]);
87 * FLAC__lpc_quantize_coefficients()
88 * --------------------------------------------------------------------
89 * Quantizes the LP coefficients. NOTE: precision + bits_per_sample
90 * must be less than 32 (sizeof(FLAC__int32)*8).
92 * IN lp_coeff[0,order-1] LP coefficients
94 * IN FLAC__MIN_QLP_COEFF_PRECISION < precision
95 * desired precision (in bits, including sign
96 * bit) of largest coefficient
97 * OUT qlp_coeff[0,order-1] quantized coefficients
98 * OUT shift # of bits to shift right to get approximated
99 * LP coefficients. NOTE: could be negative.
100 * RETURN 0 => quantization OK
101 * 1 => coefficients require too much shifting for *shift to
102 * fit in the LPC subframe header. 'shift' is unset.
103 * 2 => coefficients are all zero, which is bad. 'shift' is
106 int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], unsigned order, unsigned precision, FLAC__int32 qlp_coeff[], int *shift);
109 * FLAC__lpc_compute_residual_from_qlp_coefficients()
110 * --------------------------------------------------------------------
111 * Compute the residual signal obtained from sutracting the predicted
112 * signal from the original.
114 * IN data[-order,data_len-1] original signal (NOTE THE INDICES!)
115 * IN data_len length of original signal
116 * IN qlp_coeff[0,order-1] quantized LP coefficients
117 * IN order > 0 LP order
118 * IN lp_quantization quantization of LP coefficients in bits
119 * OUT residual[0,data_len-1] residual signal
121 void FLAC__lpc_compute_residual_from_qlp_coefficients(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[]);
122 void FLAC__lpc_compute_residual_from_qlp_coefficients_wide(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[]);
124 # ifdef FLAC__CPU_IA32
125 # ifdef FLAC__HAS_NASM
126 void FLAC__lpc_compute_residual_from_qlp_coefficients_asm_ia32(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[]);
127 void FLAC__lpc_compute_residual_from_qlp_coefficients_asm_ia32_mmx(const FLAC__int32 data[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 residual[]);
133 * FLAC__lpc_restore_signal()
134 * --------------------------------------------------------------------
135 * Restore the original signal by summing the residual and the
138 * IN residual[0,data_len-1] residual signal
139 * IN data_len length of original signal
140 * IN qlp_coeff[0,order-1] quantized LP coefficients
141 * IN order > 0 LP order
142 * IN lp_quantization quantization of LP coefficients in bits
143 * *** IMPORTANT: the caller must pass in the historical samples:
144 * IN data[-order,-1] previously-reconstructed historical samples
145 * OUT data[0,data_len-1] original signal
147 void FLAC__lpc_restore_signal(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
148 void FLAC__lpc_restore_signal_wide(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
150 # ifdef FLAC__CPU_IA32
151 # ifdef FLAC__HAS_NASM
152 void FLAC__lpc_restore_signal_asm_ia32(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
153 void FLAC__lpc_restore_signal_asm_ia32_mmx(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
154 # endif /* FLAC__HAS_NASM */
155 # elif defined FLAC__CPU_PPC
156 void FLAC__lpc_restore_signal_asm_ppc_altivec_16(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
157 void FLAC__lpc_restore_signal_asm_ppc_altivec_16_order8(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
158 # endif/* FLAC__CPU_IA32 || FLAC__CPU_PPC */
159 #endif /* FLAC__NO_ASM */
162 * FLAC__lpc_compute_expected_bits_per_residual_sample()
163 * --------------------------------------------------------------------
164 * Compute the expected number of bits per residual signal sample
165 * based on the LP error (which is related to the residual variance).
167 * IN lpc_error >= 0.0 error returned from calculating LP coefficients
168 * IN total_samples > 0 # of samples in residual signal
169 * RETURN expected bits per sample
171 FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample(FLAC__real lpc_error, unsigned total_samples);
172 FLAC__real FLAC__lpc_compute_expected_bits_per_residual_sample_with_error_scale(FLAC__real lpc_error, double error_scale);
175 * FLAC__lpc_compute_best_order()
176 * --------------------------------------------------------------------
177 * Compute the best order from the array of signal errors returned
178 * during coefficient computation.
180 * IN lpc_error[0,max_order-1] >= 0.0 error returned from calculating LP coefficients
181 * IN max_order > 0 max LP order
182 * IN total_samples > 0 # of samples in residual signal
183 * IN bits_per_signal_sample # of bits per sample in the original signal
184 * RETURN [1,max_order] best order
186 unsigned FLAC__lpc_compute_best_order(const FLAC__real lpc_error[], unsigned max_order, unsigned total_samples, unsigned bits_per_signal_sample);