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Diffstat (limited to 'contrib/libmpcdec/requant.c')
| -rw-r--r-- | contrib/libmpcdec/requant.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/contrib/libmpcdec/requant.c b/contrib/libmpcdec/requant.c new file mode 100644 index 000000000..2e4c98b62 --- /dev/null +++ b/contrib/libmpcdec/requant.c @@ -0,0 +1,120 @@ +/* + Copyright (c) 2005, The Musepack Development Team + All rights reserved. + + 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 The Musepack Development Team 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 COPYRIGHT + OWNER 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. +*/ + +/// \file requant.c +/// Requantization function implementations. +/// \todo document me + +#include <mpcdec/mpcdec.h> +#include <mpcdec/internal.h> + +/* C O N S T A N T S */ +// bits per sample for chosen quantizer +const mpc_uint32_t Res_bit [18] = { + 0, 0, 0, 0, 0, 0, 0, 0, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 +}; + +// coefficients for requantization +// 65536/step bzw. 65536/(2*D+1) + +#define _(X) MAKE_MPC_SAMPLE_EX(X,14) + +const MPC_SAMPLE_FORMAT __Cc [1 + 18] = { + _(111.285962475327f), // 32768/2/255*sqrt(3) + _(65536.000000000000f), _(21845.333333333332f), _(13107.200000000001f), _(9362.285714285713f), + _(7281.777777777777f), _(4369.066666666666f), _(2114.064516129032f), _(1040.253968253968f), + _(516.031496062992f), _(257.003921568627f), _(128.250489236790f), _(64.062561094819f), + _(32.015632633121f), _(16.003907203907f), _(8.000976681723f), _(4.000244155527f), + _(2.000061037018f), _(1.000015259021f) +}; + +#undef _ + +// offset for requantization +// 2*D+1 = steps of quantizer +const mpc_int32_t __Dc [1 + 18] = { + 2, + 0, 1, 2, 3, 4, 7, 15, 31, 63, + 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767 +}; + +#ifdef MPC_FIXED_POINT +static mpc_uint32_t find_shift(double fval) +{ + mpc_int64_t val = (mpc_int64_t)fval; + mpc_uint32_t ptr = 0; + if (val<0) val = -val; + while(val) {val>>=1;ptr++;} + + return ptr > 31 ? 0 : 31 - ptr; +} +#endif + +/* F U N C T I O N S */ + +#define SET_SCF(N,X) d->SCF[N] = MAKE_MPC_SAMPLE_EX(X,d->SCF_shift[N] = (unsigned char)find_shift(X)); + +void +mpc_decoder_scale_output(mpc_decoder *d, double factor) +{ + mpc_int32_t n; + double f1; + double f2; +#ifndef MPC_FIXED_POINT + factor *= 1.0 / (double)(1<<(MPC_FIXED_POINT_SHIFT-1)); +#else + factor *= 1.0 / (double)(1<<(16 - MPC_FIXED_POINT_SHIFT)); +#endif + f1 = f2 = factor; + + // handles +1.58...-98.41 dB, where's scf[n] / scf[n-1] = 1.20050805774840750476 + + SET_SCF(1,factor); + + f1 *= 0.83298066476582673961; + f2 *= 1/0.83298066476582673961; + + for ( n = 1; n <= 128; n++ ) { + SET_SCF((unsigned char)(1+n),f1); + SET_SCF((unsigned char)(1-n),f2); + f1 *= 0.83298066476582673961; + f2 *= 1/0.83298066476582673961; + } +} + +void +mpc_decoder_initialisiere_quantisierungstabellen(mpc_decoder *d, double scale_factor) +{ + mpc_decoder_scale_output(d, scale_factor); +} |