android 卡拉ok 源码

/* * Layer3.java -- MPEG 1.0/2.0/2.5 Audio Layer III (MP3) 解码 * Copyright (C) 2010 * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * If you would like to negotiate alternate licensing terms, you may do * so by contacting the author: <http://jmp123.sourceforge.net/> */ package jmp123.decoder; public final class Layer3 implements IFrame123 { private static Header objHeader; private static Synthesis objFilter; private static BitStream bsMainInfo; private static int maxGr; private static int intChannels; private static int[] intSfbIdxLong; private static int[] intSfbIdxShort; private static boolean isMPEG1; private static boolean isIntensityStereo; //true:强度立体声 public Layer3(BitStream bs,Header h) { bsMainInfo = bs; objHeader = h; intChannels = objHeader.getChannels(); objFilter = new Synthesis(intChannels); isMPEG1 = objHeader.getVersion() == Header.MPEG1 ? true : false; maxGr = isMPEG1 ? 2 : 1; objSI = new SideInfo(); objHuffBits = new HuffmanBits(bsMainInfo); bsSI = new BitStream(36); scfL = new int[2][23]; scfS = new int[2][3][13]; is = new int[32 * 18 + 4]; xr = new float[2][32][18]; intWidthLong = new int[22]; intWidthShort = new int[13]; floatRawOut = new float[36]; floatPrevBlck = new float[2][32][18]; cs = new float[] { 0.85749293f, 0.8817420f, 0.94962865f, 0.98331459f, 0.99551782f, 0.99916056f, 0.99989920f, 0.99999316f }; ca = new float[] { -0.51449576f, -0.47173197f, -0.31337745f, -0.18191320f, -0.09457419f, -0.04096558f, -0.0141986f, -3.69997467e-3f}; int i; /* * floatPowIS[]:用于查表求 v^(4/3)，v是经哈夫曼解码出的一个(正)值，该值的范围是0..8191 */ floatPowIS = new float[8207]; for (i = 0; i < 8207; i++) floatPowIS[i] = (float) Math.pow(i, 4.0 / 3.0); /* * pow_2[] -- 用于查表求 2 ^ exp, exp 是长块(long block)逆量化的指数 */ floatPow2 = new float[256 + 118 + 4]; for (i = -256; i < 118 + 4; i++) floatPow2[i + 256] = (float) Math.pow(2.0, -0.25 * (i + 210)); //--------------------------------------------------------------------- //待解码文件的不同特征用到不同的变量.初始化: //--------------------------------------------------------------------- int intSfreq = objHeader.getSampleFrequency(); intSfreq += isMPEG1 ? 0 : ((objHeader.getVersion() == Header.MPEG2) ? 3 : 6); /* * ANNEX B,Table 3-B.8. Layer III scalefactor bands */ switch (intSfreq) { case 0: /* MPEG 1, sampling_frequency=0, 44.1kHz */ intSfbIdxLong = new int[] { 0, 4, 8, 12, 16, 20, 24, 30, 36, 44, 52, 62, 74, 90, 110, 134, 162, 196, 238, 288, 342, 418, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 16, 22, 30, 40, 52, 66, 84, 106, 136, 192 }; break; case 1: /* MPEG 1, sampling_frequency=1, 48kHz */ intSfbIdxLong = new int[] { 0, 4, 8, 12, 16, 20, 24, 30, 36, 42, 50, 60, 72, 88, 106, 128, 156, 190, 230, 276, 330, 384, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 16, 22, 28, 38, 50, 64, 80, 100, 126, 192 }; break; case 2: /* MPEG 1, sampling_frequency=2, 32kHz */ intSfbIdxLong = new int[] { 0, 4, 8, 12, 16, 20, 24, 30, 36, 44, 54, 66, 82, 102, 126, 156, 194, 240, 296, 364, 448, 550, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 16, 22, 30, 42, 58, 78, 104, 138, 180, 192 }; break; case 3: /* MPEG 2, sampling_frequency=0, 22.05kHz */ intSfbIdxLong = new int[] { 0, 6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96, 116, 140, 168, 200, 238, 284, 336, 396, 464, 522, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 18, 24, 32, 42, 56, 74, 100, 132, 174, 192 }; break; case 4: /* MPEG 2, sampling_frequency=1, 24kHz */ intSfbIdxLong = new int[] { 0, 6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96, 114, 136, 162, 194, 232, 278, 330, 394, 464, 540, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 18, 26, 36, 48, 62, 80, 104, 136, 180, 192 }; break; case 5: /* MPEG 2, sampling_frequency=2, 16kHz */ intSfbIdxLong = new int[] { 0, 6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96, 116, 140, 168, 200, 238, 284, 336, 396, 464, 522, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 18, 26, 36, 48, 62, 80, 104, 134, 174, 192 }; break; case 6: /* MPEG 2.5, sampling_frequency=0, 11.025kHz */ intSfbIdxLong = new int[] { 0, 6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96, 116, 140, 168, 200, 238, 284, 336, 396, 464, 522, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 18, 26, 36, 48, 62, 80, 104, 134, 174, 192 }; break; case 7: /* MPEG 2.5, sampling_frequency=1, 12kHz */ intSfbIdxLong = new int[] { 0, 6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96, 116, 140, 168, 200, 238, 284, 336, 396, 464, 522, 576 }; intSfbIdxShort = new int[] { 0, 4, 8, 12, 18, 26, 36, 48, 62, 80, 104, 134, 174, 192 }; break; case 8: /* MPEG 2.5, sampling_frequency=2, 8kHz */ intSfbIdxLong = new int[] { 0, 12, 24, 36, 48, 60, 72, 88, 108, 132, 160, 192, 232, 280, 336, 400, 476, 566, 568, 570, 572, 574, 576 }; intSfbIdxShort = new int[] { 0, 8, 16, 24, 36, 52, 72, 96, 124, 160, 162, 164, 166, 192 }; break; } for (i = 0; i < 22; i++) intWidthLong[i] = intSfbIdxLong[i + 1] - intSfbIdxLong[i]; for (i = 0; i < 13; i++) intWidthShort[i] = intSfbIdxShort[i + 1] - intSfbIdxShort[i]; //--------------------------------------------------------------------- //强度立体声: isIntensityStereo = objHeader.isIntensity(); if(isIntensityStereo) { if (isMPEG1) //MPEG 1.0 is_coef = new float[] { 0.0f, 0.211324865f, 0.366025404f, 0.5f, 0.633974596f, 0.788675135f, 1.0f }; else //MPEG 2.0/2.5 lsf_is_coef = new float[][] { { 0.840896415f, 0.707106781f, 0.594603558f, 0.5f, 0.420448208f, 0.353553391f, 0.297301779f, 0.25f, 0.210224104f, 0.176776695f, 0.148650889f, 0.125f, 0.105112052f, 0.088388348f, 0.074325445f }, { 0.707106781f, 0.5f, 0.353553391f, 0.25f, 0.176776695f, 0.125f, 0.088388348f, 0.0625f, 0.044194174f, 0.03125f, 0.022097087f, 0.015625f, 0.011048543f, 0.0078125f, 0.005524272f } }; } //----------------------------------------------------------------- //MPEG 2.0/2.5 if (!isMPEG1) { i_slen2 = new int[256]; // MPEG 2.0 slen for intensity stereo n_slen2 = new int[512]; // MPEG 2.0 slen for 'normal' mode nr_of_sfb = new byte[][][] { //ISO/IEC 13818-3 subclause 2.4.3.2 nr_of_sfbx x=1..4 { { 6, 5, 5, 5 }, { 6, 5, 7, 3 }, { 11, 10, 0, 0 }, { 7, 7, 7, 0 }, { 6, 6, 6, 3 }, { 8, 8, 5, 0 } }, { { 9, 9, 9, 9 }, { 9, 9, 12, 6 }, { 18, 18, 0, 0 }, { 12, 12, 12, 0 }, { 12, 9, 9, 6 }, { 15, 12, 9, 0 } }, { { 6, 9, 9, 9 }, { 6, 9, 12, 6 }, { 15, 18, 0, 0 }, { 6, 15, 12, 0 }, { 6, 12, 9, 6 }, { 6, 18, 9, 0 } } }; //ISO/IEC 13818-3 subclause 2.4.3.2 slenx x=1..4 int j, k, l, n; for (i = 0; i < 5; i++) for (j = 0; j < 6; j++) for (k = 0; k < 6; k++) { n = k + j * 6 + i * 36; i_slen2[n] = i | (j << 3) | (k << 6) | (3 << 12); } for (i = 0; i < 4; i++) for (j = 0; j < 4; j++) for (k = 0; k < 4; k++) { n = k + (j << 2) + (i << 4); i_slen2[n + 180] = i | (j << 3) | (k << 6) | (4 << 12); } for (i = 0; i < 4