1 /* ------------------------------------------------------------------ 2 * Copyright (C) 1998-2009 PacketVideo 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either 13 * express or implied. 14 * See the License for the specific language governing permissions 15 * and limitations under the License. 16 * ------------------------------------------------------------------- 17 */ 18 /* 19 ------------------------------------------------------------------------------ 20 21 PacketVideo Corp. 22 MP3 Decoder Library 23 24 Filename: pvmp3_poly_phase_synthesis.cpp 25 26 27 Date: 09/21/2007 28 29 ------------------------------------------------------------------------------ 30 REVISION HISTORY 31 32 33 Description: 34 35 ------------------------------------------------------------------------------ 36 INPUT AND OUTPUT DEFINITIONS 37 38 Input 39 tmp3dec_chan *pChVars, decoder state structure per channel 40 int32 numChannels, number of channels 41 e_equalization equalizerType, equalization mode 42 int16 *outPcm pointer to the PCM output data 43 44 Output 45 int16 *outPcm pointer to the PCM output data 46 47 ------------------------------------------------------------------------------ 48 FUNCTION DESCRIPTION 49 50 polyphase synthesis 51 Each time the subband samples for all 32 polyphase subbands of one 52 channel have been calculated, they can be applied to the synthesis 53 subband filter and 32 consecutive audio samples can be calculated 54 55 ------------------------------------------------------------------------------ 56 REQUIREMENTS 57 58 59 ------------------------------------------------------------------------------ 60 REFERENCES 61 62 [1] ISO MPEG Audio Subgroup Software Simulation Group (1996) 63 ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension 64 65 ------------------------------------------------------------------------------ 66 PSEUDO-CODE 67 68 ------------------------------------------------------------------------------ 69 */ 70 71 72 /*---------------------------------------------------------------------------- 73 ; INCLUDES 74 ----------------------------------------------------------------------------*/ 75 76 #include "pvmp3_poly_phase_synthesis.h" 77 #include "pvmp3_polyphase_filter_window.h" 78 #include "pv_mp3dec_fxd_op.h" 79 #include "pvmp3_dec_defs.h" 80 #include "pvmp3_dct_16.h" 81 #include "pvmp3_equalizer.h" 82 #include "mp3_mem_funcs.h" 83 84 85 /*---------------------------------------------------------------------------- 86 ; MACROS 87 ; Define module specific macros here 88 ----------------------------------------------------------------------------*/ 89 90 91 /*---------------------------------------------------------------------------- 92 ; DEFINES 93 ; Include all pre-processor statements here. Include conditional 94 ; compile variables also. 95 ----------------------------------------------------------------------------*/ 96 97 /*---------------------------------------------------------------------------- 98 ; LOCAL FUNCTION DEFINITIONS 99 ; Function Prototype declaration 100 ----------------------------------------------------------------------------*/ 101 102 /*---------------------------------------------------------------------------- 103 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS 104 ; Variable declaration - defined here and used outside this module 105 ----------------------------------------------------------------------------*/ 106 107 /*---------------------------------------------------------------------------- 108 ; EXTERNAL FUNCTION REFERENCES 109 ; Declare functions defined elsewhere and referenced in this module 110 ----------------------------------------------------------------------------*/ 111 112 /*---------------------------------------------------------------------------- 113 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES 114 ; Declare variables used in this module but defined elsewhere 115 ----------------------------------------------------------------------------*/ 116 117 118 /*---------------------------------------------------------------------------- 119 ; FUNCTION CODE 120 ----------------------------------------------------------------------------*/ 121 122 void pvmp3_poly_phase_synthesis(tmp3dec_chan *pChVars, 123 int32 numChannels, 124 e_equalization equalizerType, 125 int16 *outPcm) 126 { 127 /* 128 * Equalizer 129 */ 130 pvmp3_equalizer(pChVars->circ_buffer, 131 equalizerType, 132 pChVars->work_buf_int32); 133 134 135 int16 * ptr_out = outPcm; 136 137 138 for (int32 band = 0; band < FILTERBANK_BANDS; band += 2) 139 { 140 int32 *inData = &pChVars->circ_buffer[544 - (band<<5)]; 141 142 /* 143 * DCT 32 144 */ 145 146 pvmp3_split(&inData[16]); 147 148 pvmp3_dct_16(&inData[16], 0); 149 pvmp3_dct_16(inData, 1); // Even terms 150 151 pvmp3_merge_in_place_N32(inData); 152 153 pvmp3_polyphase_filter_window(inData, 154 ptr_out, 155 numChannels); 156 157 inData -= SUBBANDS_NUMBER; 158 159 /* 160 * DCT 32 161 */ 162 163 pvmp3_split(&inData[16]); 164 165 pvmp3_dct_16(&inData[16], 0); 166 pvmp3_dct_16(inData, 1); // Even terms 167 168 pvmp3_merge_in_place_N32(inData); 169 170 pvmp3_polyphase_filter_window(inData, 171 ptr_out + (numChannels << 5), 172 numChannels); 173 174 ptr_out += (numChannels << 6); 175 176 inData -= SUBBANDS_NUMBER; 177 178 }/* end band loop */ 179 180 pv_memmove(&pChVars->circ_buffer[576], 181 pChVars->circ_buffer, 182 480*sizeof(*pChVars->circ_buffer)); 183 184 } 185 186 187 188
