sf_table.h

00001 /*
00002  * libmad - MPEG audio decoder library
00003  * Copyright (C) 2000-2004 Underbit Technologies, Inc.
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License as published by
00007  * the Free Software Foundation; either version 2 of the License, or
00008  * (at your option) any later version.
00009  *
00010  * This program is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  * GNU General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU General Public License
00016  * along with this program; if not, write to the Free Software
00017  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00018  *
00019  * $Id: sf_table.c,v 1.1 2010/11/23 20:12:57 andy Exp $
00020  */
00021 
00022 /*
00023  * These are the scalefactor values for Layer I and Layer II.
00024  * The values are from Table B.1 of ISO/IEC 11172-3.
00025  *
00026  * There is some error introduced by the 32-bit fixed-point representation;
00027  * the amount of error is shown. For 16-bit PCM output, this shouldn't be
00028  * too much of a problem.
00029  *
00030  * Strictly speaking, Table B.1 has only 63 entries (0-62), thus a strict
00031  * interpretation of ISO/IEC 11172-3 would suggest that a scalefactor index of
00032  * 63 is invalid. However, for better compatibility with current practices, we
00033  * add a 64th entry.
00034  */
00035 static
00036 mad_fixed_t const sf_table[64] = {
00037 
00038   MAD_F(0x20000000),  /* 2.000000000000 => 2.000000000000, e  0.000000000000 */
00039   MAD_F(0x1965fea5),  /* 1.587401051968 => 1.587401051074, e  0.000000000894 */
00040   MAD_F(0x1428a2fa),  /* 1.259921049895 => 1.259921051562, e -0.000000001667 */
00041   MAD_F(0x10000000),  /* 1.000000000000 => 1.000000000000, e  0.000000000000 */
00042   MAD_F(0x0cb2ff53),  /* 0.793700525984 => 0.793700527400, e -0.000000001416 */
00043   MAD_F(0x0a14517d),  /* 0.629960524947 => 0.629960525781, e -0.000000000833 */
00044   MAD_F(0x08000000),  /* 0.500000000000 => 0.500000000000, e  0.000000000000 */
00045   MAD_F(0x06597fa9),  /* 0.396850262992 => 0.396850261837, e  0.000000001155 */
00046 
00047   MAD_F(0x050a28be),  /* 0.314980262474 => 0.314980261028, e  0.000000001446 */
00048   MAD_F(0x04000000),  /* 0.250000000000 => 0.250000000000, e  0.000000000000 */
00049   MAD_F(0x032cbfd5),  /* 0.198425131496 => 0.198425132781, e -0.000000001285 */
00050   MAD_F(0x0285145f),  /* 0.157490131237 => 0.157490130514, e  0.000000000723 */
00051   MAD_F(0x02000000),  /* 0.125000000000 => 0.125000000000, e  0.000000000000 */
00052   MAD_F(0x01965fea),  /* 0.099212565748 => 0.099212564528, e  0.000000001220 */
00053   MAD_F(0x01428a30),  /* 0.078745065618 => 0.078745067120, e -0.000000001501 */
00054   MAD_F(0x01000000),  /* 0.062500000000 => 0.062500000000, e  0.000000000000 */
00055 
00056   MAD_F(0x00cb2ff5),  /* 0.049606282874 => 0.049606282264, e  0.000000000610 */
00057   MAD_F(0x00a14518),  /* 0.039372532809 => 0.039372533560, e -0.000000000751 */
00058   MAD_F(0x00800000),  /* 0.031250000000 => 0.031250000000, e  0.000000000000 */
00059   MAD_F(0x006597fb),  /* 0.024803141437 => 0.024803142995, e -0.000000001558 */
00060   MAD_F(0x0050a28c),  /* 0.019686266405 => 0.019686266780, e -0.000000000375 */
00061   MAD_F(0x00400000),  /* 0.015625000000 => 0.015625000000, e  0.000000000000 */
00062   MAD_F(0x0032cbfd),  /* 0.012401570719 => 0.012401569635, e  0.000000001084 */
00063   MAD_F(0x00285146),  /* 0.009843133202 => 0.009843133390, e -0.000000000188 */
00064 
00065   MAD_F(0x00200000),  /* 0.007812500000 => 0.007812500000, e  0.000000000000 */
00066   MAD_F(0x001965ff),  /* 0.006200785359 => 0.006200786680, e -0.000000001321 */
00067   MAD_F(0x001428a3),  /* 0.004921566601 => 0.004921566695, e -0.000000000094 */
00068   MAD_F(0x00100000),  /* 0.003906250000 => 0.003906250000, e  0.000000000000 */
00069   MAD_F(0x000cb2ff),  /* 0.003100392680 => 0.003100391477, e  0.000000001202 */
00070   MAD_F(0x000a1451),  /* 0.002460783301 => 0.002460781485, e  0.000000001816 */
00071   MAD_F(0x00080000),  /* 0.001953125000 => 0.001953125000, e  0.000000000000 */
00072   MAD_F(0x00065980),  /* 0.001550196340 => 0.001550197601, e -0.000000001262 */
00073 
00074   MAD_F(0x00050a29),  /* 0.001230391650 => 0.001230392605, e -0.000000000955 */
00075   MAD_F(0x00040000),  /* 0.000976562500 => 0.000976562500, e  0.000000000000 */
00076   MAD_F(0x00032cc0),  /* 0.000775098170 => 0.000775098801, e -0.000000000631 */
00077   MAD_F(0x00028514),  /* 0.000615195825 => 0.000615194440, e  0.000000001385 */
00078   MAD_F(0x00020000),  /* 0.000488281250 => 0.000488281250, e  0.000000000000 */
00079   MAD_F(0x00019660),  /* 0.000387549085 => 0.000387549400, e -0.000000000315 */
00080   MAD_F(0x0001428a),  /* 0.000307597913 => 0.000307597220, e  0.000000000693 */
00081   MAD_F(0x00010000),  /* 0.000244140625 => 0.000244140625, e  0.000000000000 */
00082 
00083   MAD_F(0x0000cb30),  /* 0.000193774542 => 0.000193774700, e -0.000000000158 */
00084   MAD_F(0x0000a145),  /* 0.000153798956 => 0.000153798610, e  0.000000000346 */
00085   MAD_F(0x00008000),  /* 0.000122070313 => 0.000122070313, e  0.000000000000 */
00086   MAD_F(0x00006598),  /* 0.000096887271 => 0.000096887350, e -0.000000000079 */
00087   MAD_F(0x000050a3),  /* 0.000076899478 => 0.000076901168, e -0.000000001689 */
00088   MAD_F(0x00004000),  /* 0.000061035156 => 0.000061035156, e  0.000000000000 */
00089   MAD_F(0x000032cc),  /* 0.000048443636 => 0.000048443675, e -0.000000000039 */
00090   MAD_F(0x00002851),  /* 0.000038449739 => 0.000038448721, e  0.000000001018 */
00091 
00092   MAD_F(0x00002000),  /* 0.000030517578 => 0.000030517578, e  0.000000000000 */
00093   MAD_F(0x00001966),  /* 0.000024221818 => 0.000024221838, e -0.000000000020 */
00094   MAD_F(0x00001429),  /* 0.000019224870 => 0.000019226223, e -0.000000001354 */
00095   MAD_F(0x00001000),  /* 0.000015258789 => 0.000015258789, e -0.000000000000 */
00096   MAD_F(0x00000cb3),  /* 0.000012110909 => 0.000012110919, e -0.000000000010 */
00097   MAD_F(0x00000a14),  /* 0.000009612435 => 0.000009611249, e  0.000000001186 */
00098   MAD_F(0x00000800),  /* 0.000007629395 => 0.000007629395, e -0.000000000000 */
00099   MAD_F(0x00000659),  /* 0.000006055454 => 0.000006053597, e  0.000000001858 */
00100 
00101   MAD_F(0x0000050a),  /* 0.000004806217 => 0.000004805624, e  0.000000000593 */
00102   MAD_F(0x00000400),  /* 0.000003814697 => 0.000003814697, e  0.000000000000 */
00103   MAD_F(0x0000032d),  /* 0.000003027727 => 0.000003028661, e -0.000000000934 */
00104   MAD_F(0x00000285),  /* 0.000002403109 => 0.000002402812, e  0.000000000296 */
00105   MAD_F(0x00000200),  /* 0.000001907349 => 0.000001907349, e -0.000000000000 */
00106   MAD_F(0x00000196),  /* 0.000001513864 => 0.000001512468, e  0.000000001396 */
00107   MAD_F(0x00000143),  /* 0.000001201554 => 0.000001203269, e -0.000000001714 */
00108   MAD_F(0x00000000)   /* this compatibility entry is not part of Table B.1 */
00109 };