1/******************************************************************************
2 *
3 *  Copyright (C) 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
27This 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
41OI_CHAR* const OI_Codec_Copyright =
42    "Copyright 2002-2007 Open Interface North America, Inc. All rights "
43    "reserved";
44
45INLINE 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 */
88INLINE 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 */
131PRIVATE 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. */
178PRIVATE 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  uint8_t* ptr = global_bs->ptr.w;
184  uint32_t value = global_bs->value;
185  OI_UINT bitPtr = global_bs->bitPtr;
186
187  const OI_UINT iter_count =
188      common->frameInfo.nrof_channels * common->frameInfo.nrof_subbands / 4;
189  do {
190    OI_UINT i;
191    for (i = 0; i < iter_count; ++i) {
192      uint32_t sf_by4 = ((uint32_t*)common->scale_factor)[i];
193      uint32_t bits_by4 = common->bits.uint32[i];
194      OI_UINT n;
195      for (n = 0; n < 4; ++n) {
196        int32_t dequant;
197        OI_UINT bits;
198        OI_INT sf;
199
200        if (OI_CPU_BYTE_ORDER == OI_LITTLE_ENDIAN_BYTE_ORDER) {
201          bits = bits_by4 & 0xFF;
202          bits_by4 >>= 8;
203          sf = sf_by4 & 0xFF;
204          sf_by4 >>= 8;
205        } else {
206          bits = (bits_by4 >> 24) & 0xFF;
207          bits_by4 <<= 8;
208          sf = (sf_by4 >> 24) & 0xFF;
209          sf_by4 <<= 8;
210        }
211        if (bits) {
212          uint32_t raw;
213          OI_BITSTREAM_READUINT(raw, bits, ptr, value, bitPtr);
214          dequant = OI_SBC_Dequant(raw, sf, bits);
215        } else {
216          dequant = 0;
217        }
218        *s++ = dequant;
219      }
220    }
221  } while (--nrof_blocks);
222}
223
224/**
225@}
226*/
227