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 <stdio.h>
38 #include "oi_bitstream.h"
39 #include "oi_codec_sbc_private.h"
40
41 OI_CHAR* const OI_Codec_Copyright =
42 "Copyright 2002-2007 Open Interface North America, Inc. All rights "
43 "reserved";
44
internal_DecoderReset(OI_CODEC_SBC_DECODER_CONTEXT * context,uint32_t * decoderData,uint32_t decoderDataBytes,OI_BYTE maxChannels,OI_BYTE pcmStride,OI_BOOL enhanced)45 INLINE OI_STATUS internal_DecoderReset(OI_CODEC_SBC_DECODER_CONTEXT* context,
46 uint32_t* decoderData,
47 uint32_t decoderDataBytes,
48 OI_BYTE maxChannels, OI_BYTE pcmStride,
49 OI_BOOL enhanced) {
50 OI_UINT i;
51 OI_STATUS status;
52
53 for (i = 0; i < sizeof(*context); i++) {
54 ((char*)context)[i] = 0;
55 }
56
57 #ifdef SBC_ENHANCED
58 context->enhancedEnabled = enhanced ? TRUE : FALSE;
59 #else
60 context->enhancedEnabled = FALSE;
61 if (enhanced) {
62 return OI_STATUS_INVALID_PARAMETERS;
63 }
64 #endif
65
66 status = OI_CODEC_SBC_Alloc(&context->common, decoderData, decoderDataBytes,
67 maxChannels, pcmStride);
68
69 if (!OI_SUCCESS(status)) {
70 return status;
71 }
72
73 context->common.codecInfo = OI_Codec_Copyright;
74 context->common.maxBitneed = 0;
75 context->limitFrameFormat = FALSE;
76 OI_SBC_ExpandFrameFields(&context->common.frameInfo);
77
78 /*PLATFORM_DECODER_RESET(context);*/
79
80 return OI_OK;
81 }
82
83 /**
84 * Read the SBC header up to but not including the joint stereo mask. The
85 * syncword has already been examined, and the enhanced mode flag set, by
86 * FindSyncword.
87 */
OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT * common,const OI_BYTE * data)88 INLINE void OI_SBC_ReadHeader(OI_CODEC_SBC_COMMON_CONTEXT* common,
89 const OI_BYTE* data) {
90 OI_CODEC_SBC_FRAME_INFO* frame = &common->frameInfo;
91 uint8_t d1;
92
93 OI_ASSERT(data[0] == OI_SBC_SYNCWORD || data[0] == OI_SBC_ENHANCED_SYNCWORD);
94
95 /* Avoid filling out all these strucutures if we already remember the values
96 * from last time. Just in case we get a stream corresponding to data[1] ==
97 * 0, DecoderReset is responsible for ensuring the lookup table entries have
98 * already been populated
99 */
100 d1 = data[1];
101 if (d1 != frame->cachedInfo) {
102 frame->freqIndex = (d1 & (BIT7 | BIT6)) >> 6;
103 frame->frequency = freq_values[frame->freqIndex];
104
105 frame->blocks = (d1 & (BIT5 | BIT4)) >> 4;
106 frame->nrof_blocks = block_values[frame->blocks];
107
108 frame->mode = (d1 & (BIT3 | BIT2)) >> 2;
109 frame->nrof_channels = channel_values[frame->mode];
110
111 frame->alloc = (d1 & BIT1) >> 1;
112
113 frame->subbands = (d1 & BIT0);
114 frame->nrof_subbands = band_values[frame->subbands];
115
116 frame->cachedInfo = d1;
117 }
118 /*
119 * For decode, the bit allocator needs to know the bitpool value
120 */
121 frame->bitpool = data[2];
122 frame->crc = data[3];
123 }
124
125 #define LOW(x) ((x)&0xf)
126 #define HIGH(x) ((x) >> 4)
127
128 /*
129 * Read scalefactor values and prepare the bitstream for OI_SBC_ReadSamples
130 */
OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT * common,const OI_BYTE * b,OI_BITSTREAM * bs)131 PRIVATE void OI_SBC_ReadScalefactors(OI_CODEC_SBC_COMMON_CONTEXT* common,
132 const OI_BYTE* b, OI_BITSTREAM* bs) {
133 OI_UINT i = common->frameInfo.nrof_subbands * common->frameInfo.nrof_channels;
134 int8_t* scale_factor = common->scale_factor;
135 OI_UINT f;
136
137 if (common->frameInfo.nrof_subbands == 8 ||
138 common->frameInfo.mode != SBC_JOINT_STEREO) {
139 if (common->frameInfo.mode == SBC_JOINT_STEREO) {
140 common->frameInfo.join = *b++;
141 } else {
142 common->frameInfo.join = 0;
143 }
144 i /= 2;
145 do {
146 *scale_factor++ = HIGH(f = *b++);
147 *scale_factor++ = LOW(f);
148 } while (--i);
149 /*
150 * In this case we know that the scale factors end on a byte boundary so all
151 * we need to do
152 * is initialize the bitstream.
153 */
154 OI_BITSTREAM_ReadInit(bs, b);
155 } else {
156 OI_ASSERT(common->frameInfo.nrof_subbands == 4 &&
157 common->frameInfo.mode == SBC_JOINT_STEREO);
158 common->frameInfo.join = HIGH(f = *b++);
159 i = (i - 1) / 2;
160 do {
161 *scale_factor++ = LOW(f);
162 *scale_factor++ = HIGH(f = *b++);
163 } while (--i);
164 *scale_factor++ = LOW(f);
165 /*
166 * In 4-subband joint stereo mode, the joint stereo information ends on a
167 * half-byte
168 * boundary, so it's necessary to use the bitstream abstraction to read it,
169 * 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. */
OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT * context,OI_BITSTREAM * global_bs)178 PRIVATE void OI_SBC_ReadSamples(OI_CODEC_SBC_DECODER_CONTEXT* context,
179 OI_BITSTREAM* global_bs) {
180 OI_CODEC_SBC_COMMON_CONTEXT* common = &context->common;
181 OI_UINT nrof_blocks = common->frameInfo.nrof_blocks;
182 int32_t* RESTRICT s = common->subdata;
183 const uint8_t* ptr = global_bs->ptr.r;
184 uint32_t value = global_bs->value;
185 OI_UINT bitPtr = global_bs->bitPtr;
186 const OI_UINT iter_count =
187 common->frameInfo.nrof_channels * common->frameInfo.nrof_subbands;
188 do {
189 OI_UINT n;
190 for (n = 0; n < iter_count; ++n) {
191 int32_t dequant;
192 OI_UINT bits = common->bits.uint8[n];
193 OI_INT sf = common->scale_factor[n];
194 if (bits) {
195 uint32_t raw;
196 OI_BITSTREAM_READUINT(raw, bits, ptr, value, bitPtr);
197 dequant = OI_SBC_Dequant(raw, sf, bits);
198 } else {
199 dequant = 0;
200 }
201 *s++ = dequant;
202 }
203 } while (--nrof_blocks);
204 }
205
206 /**
207 @}
208 */
209