1 /*
2 Copyright (c) 2005-2009, The Musepack Development Team
3 All rights reserved.
4
5 Redistribution and use in source and binary forms, with or without
6 modification, are permitted provided that the following conditions are
7 met:
8
9 * Redistributions of source code must retain the above copyright
10 notice, this list of conditions and the following disclaimer.
11
12 * Redistributions in binary form must reproduce the above
13 copyright notice, this list of conditions and the following
14 disclaimer in the documentation and/or other materials provided
15 with the distribution.
16
17 * Neither the name of the The Musepack Development Team nor the
18 names of its contributors may be used to endorse or promote
19 products derived from this software without specific prior
20 written permission.
21
22 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
25 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
26 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
28 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
32 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 */
34 /// \file requant.c
35 /// Requantization function implementations.
36 /// \todo document me
37 #include "mpcdec.h"
38
39 #include "requant.h"
40 #include "mpcdec_math.h"
41 #include "decoder.h"
42
43 /* C O N S T A N T S */
44 // Bits per sample for chosen quantizer
45 const mpc_uint8_t Res_bit [18] = {
46 0, 0, 0, 0, 0, 0, 0, 0, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16
47 };
48
49 // Requantization coefficients
50 // 65536/step bzw. 65536/(2*D+1)
51
52 #define _(X) MAKE_MPC_SAMPLE_EX(X,14)
53
54 const MPC_SAMPLE_FORMAT __Cc [1 + 18] = {
55 _(111.285962475327f), // 32768/2/255*sqrt(3)
56 _(65536.000000000000f), _(21845.333333333332f), _(13107.200000000001f), _(9362.285714285713f),
57 _(7281.777777777777f), _(4369.066666666666f), _(2114.064516129032f), _(1040.253968253968f),
58 _(516.031496062992f), _(257.003921568627f), _(128.250489236790f), _(64.062561094819f),
59 _(32.015632633121f), _(16.003907203907f), _(8.000976681723f), _(4.000244155527f),
60 _(2.000061037018f), _(1.000015259021f)
61 };
62
63 #undef _
64
65 // Requantization offset
66 // 2*D+1 = steps of quantizer
67 const mpc_int16_t __Dc [1 + 18] = {
68 2,
69 0, 1, 2, 3, 4, 7, 15, 31, 63,
70 127, 255, 511, 1023, 2047, 4095, 8191, 16383, 32767
71 };
72
73 #ifdef MPC_FIXED_POINT
find_shift(double fval)74 static mpc_uint32_t find_shift(double fval)
75 {
76 mpc_int64_t val = (mpc_int64_t) fval;
77 mpc_uint32_t ptr = 0;
78 if(val<0)
79 val = -val;
80 while(val)
81 {
82 val >>= 1;
83 ptr++;
84 }
85 return ptr > 31 ? 0 : 31 - ptr;
86 }
87 #endif
88
89 /* F U N C T I O N S */
90
91 #define SET_SCF(N,X) d->SCF[N] = MAKE_MPC_SAMPLE_EX(X,d->SCF_shift[N] = (mpc_uint8_t) find_shift(X));
92
93 void
mpc_decoder_scale_output(mpc_decoder * d,double factor)94 mpc_decoder_scale_output(mpc_decoder *d, double factor)
95 {
96 mpc_int32_t n; double f1, f2;
97
98 #ifndef MPC_FIXED_POINT
99 factor *= 1.0 / (double) (1<<(MPC_FIXED_POINT_SHIFT-1));
100 #else
101 factor *= 1.0 / (double) (1<<(16-MPC_FIXED_POINT_SHIFT));
102 #endif
103 f1 = f2 = factor;
104
105 // handles +1.58...-98.41 dB, where's scf[n] / scf[n-1] = 1.20050805774840750476
106
107 SET_SCF(1,factor);
108
109 f1 *= 0.83298066476582673961;
110 f2 *= 1/0.83298066476582673961;
111
112 for ( n = 1; n <= 128; n++ ) {
113 SET_SCF((mpc_uint8_t)(1+n),f1);
114 SET_SCF((mpc_uint8_t)(1-n),f2);
115 f1 *= 0.83298066476582673961;
116 f2 *= 1/0.83298066476582673961;
117 }
118 }
119
120 void
mpc_decoder_init_quant(mpc_decoder * d,double scale_factor)121 mpc_decoder_init_quant(mpc_decoder *d, double scale_factor)
122 {
123 mpc_decoder_scale_output(d, scale_factor);
124 }
125