1 /****************************************************************************** 2 * 3 * Copyright (C) 2014 The Android Open Source Project 4 * Copyright 2003 - 2004 Open Interface North America, Inc. All rights reserved. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at: 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 * 18 ******************************************************************************/ 19 20 /********************************************************************************** 21 $Revision: #1 $ 22 ***********************************************************************************/ 23 24 /** 25 @file 26 This file drives SBC decoding. 27 28 @ingroup codec_internal 29 */ 30 31 /** 32 @addtogroup codec_internal 33 @{ 34 */ 35 36 #include "oi_codec_sbc_private.h" 37 #include "oi_bitstream.h" 38 #include <stdio.h> 39 40 OI_CHAR * const OI_Codec_Copyright = "Copyright 2002-2007 Open Interface North America, Inc. All rights reserved"; 41 42 INLINE OI_STATUS internal_DecoderReset(OI_CODEC_SBC_DECODER_CONTEXT *context, 43 OI_UINT32 *decoderData, 44 OI_UINT32 decoderDataBytes, 45 OI_BYTE maxChannels, 46 OI_BYTE pcmStride, 47 OI_BOOL enhanced) 48 { 49 OI_UINT i; 50 OI_STATUS status; 51 52 for (i = 0; i < sizeof(*context); i++) { 53 ((char *)context)[i] = 0; 54 } 55 56 #ifdef SBC_ENHANCED 57 context->enhancedEnabled = enhanced ? TRUE : FALSE; 58 #else 59 context->enhancedEnabled = FALSE; 60 if (enhanced){ 61 return OI_STATUS_INVALID_PARAMETERS; 62 } 63 #endif 64 65 status = OI_CODEC_SBC_Alloc(&context->common, decoderData, decoderDataBytes, maxChannels, pcmStride); 66 67 if (!OI_SUCCESS(status)) { 68 return status; 69 } 70 71 context->common.codecInfo = OI_Codec_Copyright; 72 context->common.maxBitneed = 0; 73 context->limitFrameFormat = FALSE; 74 OI_SBC_ExpandFrameFields(&context->common.frameInfo); 75 76 /*PLATFORM_DECODER_RESET(context);*/ 77 78 return OI_OK; 79 } 80 81 82 83 84 /** 85 * Read the SBC header up to but not including the joint stereo mask. The syncword has already been 86 * examined, and the enhanced mode flag set, by FindSyncword. 87 */ 88 INLINE void OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT *common, const OI_BYTE *data) 89 { 90 OI_CODEC_SBC_FRAME_INFO *frame = &common->frameInfo; 91 OI_UINT8 d1; 92 93 94 OI_ASSERT(data[0] == OI_SBC_SYNCWORD || data[0] == OI_SBC_ENHANCED_SYNCWORD); 95 96 /* Avoid filling out all these strucutures if we already remember the values 97 * from last time. Just in case we get a stream corresponding to data[1] == 98 * 0, DecoderReset is responsible for ensuring the lookup table entries have 99 * already been populated 100 */ 101 d1 = data[1]; 102 if (d1 != frame->cachedInfo) { 103 104 frame->freqIndex = (d1 & (BIT7 | BIT6)) >> 6; 105 frame->frequency = freq_values[frame->freqIndex]; 106 107 frame->blocks = (d1 & (BIT5 | BIT4)) >> 4; 108 frame->nrof_blocks = block_values[frame->blocks]; 109 110 frame->mode = (d1 & (BIT3 | BIT2)) >> 2; 111 frame->nrof_channels = channel_values[frame->mode]; 112 113 frame->alloc = (d1 & BIT1) >> 1; 114 115 frame->subbands = (d1 & BIT0); 116 frame->nrof_subbands = band_values[frame->subbands]; 117 118 frame->cachedInfo = d1; 119 } 120 /* 121 * For decode, the bit allocator needs to know the bitpool value 122 */ 123 frame->bitpool = data[2]; 124 frame->crc = data[3]; 125 } 126 127 128 #define LOW(x) ((x)& 0xf) 129 #define HIGH(x) ((x) >> 4) 130 131 /* 132 * Read scalefactor values and prepare the bitstream for OI_SBC_ReadSamples 133 */ 134 PRIVATE void OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT *common, 135 const OI_BYTE *b, 136 OI_BITSTREAM *bs) 137 { 138 OI_UINT i = common->frameInfo.nrof_subbands * common->frameInfo.nrof_channels; 139 OI_INT8 *scale_factor = common->scale_factor; 140 OI_UINT f; 141 142 if (common->frameInfo.nrof_subbands == 8 || common->frameInfo.mode != SBC_JOINT_STEREO) { 143 if (common->frameInfo.mode == SBC_JOINT_STEREO) { 144 common->frameInfo.join = *b++; 145 } else { 146 common->frameInfo.join = 0; 147 } 148 i /= 2; 149 do { 150 *scale_factor++ = HIGH(f = *b++); 151 *scale_factor++ = LOW(f); 152 } while (--i); 153 /* 154 * In this case we know that the scale factors end on a byte boundary so all we need to do 155 * is initialize the bitstream. 156 */ 157 OI_BITSTREAM_ReadInit(bs, b); 158 } else { 159 OI_ASSERT(common->frameInfo.nrof_subbands == 4 && common->frameInfo.mode == SBC_JOINT_STEREO); 160 common->frameInfo.join = HIGH(f = *b++); 161 i = (i - 1) / 2; 162 do { 163 *scale_factor++ = LOW(f); 164 *scale_factor++ = HIGH(f = *b++); 165 } while (--i); 166 *scale_factor++ = LOW(f); 167 /* 168 * In 4-subband joint stereo mode, the joint stereo information ends on a half-byte 169 * boundary, so it's necessary to use the bitstream abstraction to read it, since 170 * OI_SBC_ReadSamples will need to pick up in mid-byte. 171 */ 172 OI_BITSTREAM_ReadInit(bs, b); 173 *scale_factor++ = OI_BITSTREAM_ReadUINT4Aligned(bs); 174 } 175 } 176 177 /** Read quantized subband samples from the input bitstream and expand them. */ 178 PRIVATE void OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT *context, OI_BITSTREAM *global_bs) 179 { 180 OI_CODEC_SBC_COMMON_CONTEXT *common = &context->common; 181 OI_UINT nrof_blocks = common->frameInfo.nrof_blocks; 182 OI_INT32 * RESTRICT s = common->subdata; 183 OI_UINT8 *ptr = global_bs->ptr.w; 184 OI_UINT32 value = global_bs->value; 185 OI_UINT bitPtr = global_bs->bitPtr; 186 187 const OI_UINT iter_count = common->frameInfo.nrof_channels * common->frameInfo.nrof_subbands / 4; 188 do { 189 OI_UINT i; 190 for (i = 0; i < iter_count; ++i) { 191 OI_UINT32 sf_by4 = ((OI_UINT32*)common->scale_factor)[i]; 192 OI_UINT32 bits_by4 = common->bits.uint32[i]; 193 OI_UINT n; 194 for (n = 0; n < 4; ++n) { 195 OI_INT32 dequant; 196 OI_UINT bits; 197 OI_INT sf; 198 199 if (OI_CPU_BYTE_ORDER == OI_LITTLE_ENDIAN_BYTE_ORDER) { 200 bits = bits_by4 & 0xFF; 201 bits_by4 >>= 8; 202 sf = sf_by4 & 0xFF; 203 sf_by4 >>= 8; 204 } else { 205 bits = (bits_by4 >> 24) & 0xFF; 206 bits_by4 <<= 8; 207 sf = (sf_by4 >> 24) & 0xFF; 208 sf_by4 <<= 8; 209 } 210 if (bits) { 211 OI_UINT32 raw; 212 OI_BITSTREAM_READUINT(raw, bits, ptr, value, bitPtr); 213 dequant = OI_SBC_Dequant(raw, sf, bits); 214 } else { 215 dequant = 0; 216 } 217 *s++ = dequant; 218 } 219 } 220 } while (--nrof_blocks); 221 } 222 223 224 225 /** 226 @} 227 */ 228
