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,
45 uint32_t* decoderData,
46 uint32_t decoderDataBytes,
47 OI_BYTE maxChannels, OI_BYTE pcmStride,
48 OI_BOOL enhanced) {
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,
66 maxChannels, pcmStride);
67
68 if (!OI_SUCCESS(status)) {
69 return status;
70 }
71
72 context->common.codecInfo = OI_Codec_Copyright;
73 context->common.maxBitneed = 0;
74 context->limitFrameFormat = FALSE;
75 OI_SBC_ExpandFrameFields(&context->common.frameInfo);
76
77 /*PLATFORM_DECODER_RESET(context);*/
78
79 return OI_OK;
80 }
81
82 /**
83 * Read the SBC header up to but not including the joint stereo mask. The
84 * syncword has already been examined, and the enhanced mode flag set, by
85 * FindSyncword.
86 */
OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT * common,const OI_BYTE * data)87 INLINE void OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT* common,
88 const OI_BYTE* data) {
89 OI_CODEC_SBC_FRAME_INFO* frame = &common->frameInfo;
90 uint8_t d1;
91
92 OI_ASSERT(data[0] == OI_SBC_SYNCWORD || data[0] == OI_SBC_ENHANCED_SYNCWORD);
93
94 /* Avoid filling out all these strucutures if we already remember the values
95 * from last time. Just in case we get a stream corresponding to data[1] ==
96 * 0, DecoderReset is responsible for ensuring the lookup table entries have
97 * already been populated
98 */
99 d1 = data[1];
100 if (d1 != frame->cachedInfo) {
101 frame->freqIndex = (d1 & (BIT7 | BIT6)) >> 6;
102 frame->frequency = freq_values[frame->freqIndex];
103
104 frame->blocks = (d1 & (BIT5 | BIT4)) >> 4;
105 frame->nrof_blocks = block_values[frame->blocks];
106
107 frame->mode = (d1 & (BIT3 | BIT2)) >> 2;
108 frame->nrof_channels = channel_values[frame->mode];
109
110 frame->alloc = (d1 & BIT1) >> 1;
111
112 frame->subbands = (d1 & BIT0);
113 frame->nrof_subbands = band_values[frame->subbands];
114
115 frame->cachedInfo = d1;
116 }
117 /*
118 * For decode, the bit allocator needs to know the bitpool value
119 */
120 frame->bitpool = data[2];
121 frame->crc = data[3];
122 }
123
124 #define LOW(x) ((x)&0xf)
125 #define HIGH(x) ((x) >> 4)
126
127 /*
128 * Read scalefactor values and prepare the bitstream for OI_SBC_ReadSamples
129 */
OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT * common,const OI_BYTE * b,OI_BITSTREAM * bs)130 PRIVATE void OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT* common,
131 const OI_BYTE* b, OI_BITSTREAM* bs) {
132 OI_UINT i = common->frameInfo.nrof_subbands * common->frameInfo.nrof_channels;
133 int8_t* scale_factor = common->scale_factor;
134 OI_UINT f;
135
136 if (common->frameInfo.nrof_subbands == 8 ||
137 common->frameInfo.mode != SBC_JOINT_STEREO) {
138 if (common->frameInfo.mode == SBC_JOINT_STEREO) {
139 common->frameInfo.join = *b++;
140 } else {
141 common->frameInfo.join = 0;
142 }
143 i /= 2;
144 do {
145 *scale_factor++ = HIGH(f = *b++);
146 *scale_factor++ = LOW(f);
147 } while (--i);
148 /*
149 * In this case we know that the scale factors end on a byte boundary so all
150 * we need to do
151 * is initialize the bitstream.
152 */
153 OI_BITSTREAM_ReadInit(bs, b);
154 } else {
155 OI_ASSERT(common->frameInfo.nrof_subbands == 4 &&
156 common->frameInfo.mode == SBC_JOINT_STEREO);
157 common->frameInfo.join = HIGH(f = *b++);
158 i = (i - 1) / 2;
159 do {
160 *scale_factor++ = LOW(f);
161 *scale_factor++ = HIGH(f = *b++);
162 } while (--i);
163 *scale_factor++ = LOW(f);
164 /*
165 * In 4-subband joint stereo mode, the joint stereo information ends on a
166 * half-byte
167 * boundary, so it's necessary to use the bitstream abstraction to read it,
168 * since
169 * OI_SBC_ReadSamples will need to pick up in mid-byte.
170 */
171 OI_BITSTREAM_ReadInit(bs, b);
172 *scale_factor++ = OI_BITSTREAM_ReadUINT4Aligned(bs);
173 }
174 }
175
176 /** Read quantized subband samples from the input bitstream and expand them. */
OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT * context,OI_BITSTREAM * global_bs)177 PRIVATE void OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT* context,
178 OI_BITSTREAM* global_bs) {
179 OI_CODEC_SBC_COMMON_CONTEXT* common = &context->common;
180 OI_UINT nrof_blocks = common->frameInfo.nrof_blocks;
181 int32_t* RESTRICT s = common->subdata;
182 const uint8_t* ptr = global_bs->ptr.r;
183 uint32_t value = global_bs->value;
184 OI_UINT bitPtr = global_bs->bitPtr;
185 const OI_UINT iter_count =
186 common->frameInfo.nrof_channels * common->frameInfo.nrof_subbands;
187 do {
188 OI_UINT n;
189 for (n = 0; n < iter_count; ++n) {
190 int32_t dequant;
191 OI_UINT bits = common->bits.uint8[n];
192 OI_INT sf = common->scale_factor[n];
193 if (bits) {
194 uint32_t raw;
195 OI_BITSTREAM_READUINT(raw, bits, ptr, value, bitPtr);
196 dequant = OI_SBC_Dequant(raw, sf, bits);
197 } else {
198 dequant = 0;
199 }
200 *s++ = dequant;
201 }
202 } while (--nrof_blocks);
203 }
204
205 /**
206 @}
207 */
208