1 /******************************************************************************
2 *
3 * Copyright 2014 The Android Open Source Project
4 * Copyright 2003 - 2004 Open Interface North America, Inc. All rights
5 * reserved.
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at:
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 ******************************************************************************/
20
21 /*******************************************************************************
22 $Revision: #1 $
23 ******************************************************************************/
24
25 /**
26 @file
27 This file drives SBC decoding.
28
29 @ingroup codec_internal
30 */
31
32 /**
33 @addtogroup codec_internal
34 @{
35 */
36
37 #include "oi_bitstream.h"
38 #include "oi_codec_sbc_private.h"
39
40 OI_CHAR* const OI_Codec_Copyright =
41 "Copyright 2002-2007 Open Interface North America, Inc. All rights "
42 "reserved";
43
internal_DecoderReset(OI_CODEC_SBC_DECODER_CONTEXT * context,uint32_t * decoderData,uint32_t decoderDataBytes,OI_BYTE maxChannels,OI_BYTE pcmStride,OI_BOOL enhanced)44 INLINE OI_STATUS internal_DecoderReset(OI_CODEC_SBC_DECODER_CONTEXT* context, uint32_t* decoderData,
45 uint32_t decoderDataBytes, OI_BYTE maxChannels,
46 OI_BYTE pcmStride, OI_BOOL enhanced) {
47 OI_UINT i;
48 OI_STATUS status;
49
50 for (i = 0; i < sizeof(*context); i++) {
51 ((char*)context)[i] = 0;
52 }
53
54 #ifdef SBC_ENHANCED
55 context->enhancedEnabled = enhanced ? TRUE : FALSE;
56 #else
57 context->enhancedEnabled = FALSE;
58 if (enhanced) {
59 return OI_STATUS_INVALID_PARAMETERS;
60 }
61 #endif
62
63 status = OI_CODEC_SBC_Alloc(&context->common, decoderData, decoderDataBytes, maxChannels,
64 pcmStride);
65
66 if (!OI_SUCCESS(status)) {
67 return status;
68 }
69
70 context->common.codecInfo = OI_Codec_Copyright;
71 context->common.maxBitneed = 0;
72 context->limitFrameFormat = FALSE;
73 OI_SBC_ExpandFrameFields(&context->common.frameInfo);
74
75 /*PLATFORM_DECODER_RESET(context);*/
76
77 return OI_OK;
78 }
79
80 /**
81 * Read the SBC header up to but not including the joint stereo mask. The
82 * syncword has already been examined, and the enhanced mode flag set, by
83 * FindSyncword.
84 */
OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT * common,const OI_BYTE * data)85 INLINE void OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT* common, const OI_BYTE* data) {
86 OI_CODEC_SBC_FRAME_INFO* frame = &common->frameInfo;
87 uint8_t d1;
88
89 OI_ASSERT(data[0] == OI_SBC_SYNCWORD || data[0] == OI_SBC_ENHANCED_SYNCWORD);
90
91 /* Avoid filling out all these strucutures if we already remember the values
92 * from last time. Just in case we get a stream corresponding to data[1] ==
93 * 0, DecoderReset is responsible for ensuring the lookup table entries have
94 * already been populated
95 */
96 d1 = data[1];
97 if (d1 != frame->cachedInfo) {
98 frame->freqIndex = (d1 & (BIT7 | BIT6)) >> 6;
99 frame->frequency = freq_values[frame->freqIndex];
100
101 frame->blocks = (d1 & (BIT5 | BIT4)) >> 4;
102 frame->nrof_blocks = block_values[frame->blocks];
103
104 frame->mode = (d1 & (BIT3 | BIT2)) >> 2;
105 frame->nrof_channels = channel_values[frame->mode];
106
107 frame->alloc = (d1 & BIT1) >> 1;
108
109 frame->subbands = (d1 & BIT0);
110 frame->nrof_subbands = band_values[frame->subbands];
111
112 frame->cachedInfo = d1;
113 }
114 /*
115 * For decode, the bit allocator needs to know the bitpool value
116 */
117 frame->bitpool = data[2];
118 frame->crc = data[3];
119 }
120
121 #define LOW(x) ((x) & 0xf)
122 #define HIGH(x) ((x) >> 4)
123
124 /*
125 * Read scalefactor values and prepare the bitstream for OI_SBC_ReadSamples
126 */
OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT * common,const OI_BYTE * b,OI_BITSTREAM * bs)127 PRIVATE void OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT* common, const OI_BYTE* b,
128 OI_BITSTREAM* bs) {
129 OI_UINT i = common->frameInfo.nrof_subbands * common->frameInfo.nrof_channels;
130 int8_t* scale_factor = common->scale_factor;
131 OI_UINT f;
132
133 if (common->frameInfo.nrof_subbands == 8 || common->frameInfo.mode != SBC_JOINT_STEREO) {
134 if (common->frameInfo.mode == SBC_JOINT_STEREO) {
135 common->frameInfo.join = *b++;
136 } else {
137 common->frameInfo.join = 0;
138 }
139 i /= 2;
140 do {
141 *scale_factor++ = HIGH(f = *b++);
142 *scale_factor++ = LOW(f);
143 } while (--i);
144 /*
145 * In this case we know that the scale factors end on a byte boundary so all
146 * we need to do
147 * is initialize the bitstream.
148 */
149 OI_BITSTREAM_ReadInit(bs, b);
150 } else {
151 OI_ASSERT(common->frameInfo.nrof_subbands == 4 && common->frameInfo.mode == SBC_JOINT_STEREO);
152 common->frameInfo.join = HIGH(f = *b++);
153 i = (i - 1) / 2;
154 do {
155 *scale_factor++ = LOW(f);
156 *scale_factor++ = HIGH(f = *b++);
157 } while (--i);
158 *scale_factor++ = LOW(f);
159 /*
160 * In 4-subband joint stereo mode, the joint stereo information ends on a
161 * half-byte
162 * boundary, so it's necessary to use the bitstream abstraction to read it,
163 * since
164 * OI_SBC_ReadSamples will need to pick up in mid-byte.
165 */
166 OI_BITSTREAM_ReadInit(bs, b);
167 *scale_factor++ = OI_BITSTREAM_ReadUINT4Aligned(bs);
168 }
169 }
170
171 /** Read quantized subband samples from the input bitstream and expand them. */
OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT * context,OI_BITSTREAM * global_bs)172 PRIVATE void OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT* context, OI_BITSTREAM* global_bs) {
173 OI_CODEC_SBC_COMMON_CONTEXT* common = &context->common;
174 OI_UINT nrof_blocks = common->frameInfo.nrof_blocks;
175 int32_t* RESTRICT s = common->subdata;
176 const uint8_t* ptr = global_bs->ptr.r;
177 uint32_t value = global_bs->value;
178 OI_UINT bitPtr = global_bs->bitPtr;
179 const OI_UINT iter_count = common->frameInfo.nrof_channels * common->frameInfo.nrof_subbands;
180 do {
181 OI_UINT n;
182 for (n = 0; n < iter_count; ++n) {
183 int32_t dequant;
184 OI_UINT bits = common->bits.uint8[n];
185 OI_INT sf = common->scale_factor[n];
186 if (bits) {
187 uint32_t raw;
188 OI_BITSTREAM_READUINT(raw, bits, ptr, value, bitPtr);
189 dequant = OI_SBC_Dequant(raw, sf, bits);
190 } else {
191 dequant = 0;
192 }
193 *s++ = dequant;
194 }
195 } while (--nrof_blocks);
196 }
197
198 /**
199 @}
200 */
201