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1 /*
2  * Bluetooth low-complexity, subband codec (SBC)
3  *
4  * Copyright (C) 2017  Aurelien Jacobs <aurel@gnuage.org>
5  * Copyright (C) 2012-2014  Intel Corporation
6  * Copyright (C) 2008-2010  Nokia Corporation
7  * Copyright (C) 2004-2010  Marcel Holtmann <marcel@holtmann.org>
8  * Copyright (C) 2004-2005  Henryk Ploetz <henryk@ploetzli.ch>
9  * Copyright (C) 2005-2006  Brad Midgley <bmidgley@xmission.com>
10  *
11  * This file is part of FFmpeg.
12  *
13  * FFmpeg is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU Lesser General Public
15  * License as published by the Free Software Foundation; either
16  * version 2.1 of the License, or (at your option) any later version.
17  *
18  * FFmpeg is distributed in the hope that it will be useful,
19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21  * Lesser General Public License for more details.
22  *
23  * You should have received a copy of the GNU Lesser General Public
24  * License along with FFmpeg; if not, write to the Free Software
25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26  */
27 
28 /**
29  * @file
30  * SBC common definitions for the encoder and decoder
31  */
32 
33 #ifndef AVCODEC_SBC_H
34 #define AVCODEC_SBC_H
35 
36 #include <stddef.h>
37 #include <stdint.h>
38 #include "libavutil/crc.h"
39 #include "libavutil/mem_internal.h"
40 
41 #define MSBC_BLOCKS 15
42 
43 /* sampling frequency */
44 #define SBC_FREQ_16000  0x00
45 #define SBC_FREQ_32000  0x01
46 #define SBC_FREQ_44100  0x02
47 #define SBC_FREQ_48000  0x03
48 
49 /* blocks */
50 #define SBC_BLK_4       0x00
51 #define SBC_BLK_8       0x01
52 #define SBC_BLK_12      0x02
53 #define SBC_BLK_16      0x03
54 
55 /* channel mode */
56 #define SBC_MODE_MONO         0x00
57 #define SBC_MODE_DUAL_CHANNEL 0x01
58 #define SBC_MODE_STEREO       0x02
59 #define SBC_MODE_JOINT_STEREO 0x03
60 
61 /* allocation method */
62 #define SBC_AM_LOUDNESS 0x00
63 #define SBC_AM_SNR      0x01
64 
65 /* subbands */
66 #define SBC_SB_4        0x00
67 #define SBC_SB_8        0x01
68 
69 /* synchronisation words */
70 #define SBC_SYNCWORD   0x9C
71 #define MSBC_SYNCWORD  0xAD
72 
73 /* extra bits of precision for the synthesis filter input data */
74 #define SBCDEC_FIXED_EXTRA_BITS 2
75 
76 /*
77  * Enforce 16 byte alignment for the data, which is supposed to be used
78  * with SIMD optimized code.
79  */
80 #define SBC_ALIGN 16
81 
82 /* This structure contains an unpacked SBC frame.
83    Yes, there is probably quite some unused space herein */
84 struct sbc_frame {
85     uint8_t frequency;
86     uint8_t blocks;
87     enum {
88         MONO         = SBC_MODE_MONO,
89         DUAL_CHANNEL = SBC_MODE_DUAL_CHANNEL,
90         STEREO       = SBC_MODE_STEREO,
91         JOINT_STEREO = SBC_MODE_JOINT_STEREO
92     } mode;
93     uint8_t channels;
94     enum {
95         LOUDNESS = SBC_AM_LOUDNESS,
96         SNR      = SBC_AM_SNR
97     } allocation;
98     uint8_t subbands;
99     uint8_t bitpool;
100     uint16_t codesize;
101 
102     /* bit number x set means joint stereo has been used in subband x */
103     uint8_t joint;
104 
105     /* only the lower 4 bits of every element are to be used */
106     DECLARE_ALIGNED(SBC_ALIGN, uint32_t, scale_factor)[2][8];
107 
108     /* raw integer subband samples in the frame */
109     DECLARE_ALIGNED(SBC_ALIGN, int32_t, sb_sample_f)[16][2][8];
110 
111     /* modified subband samples */
112     DECLARE_ALIGNED(SBC_ALIGN, int32_t, sb_sample)[16][2][8];
113 
114     const AVCRC *crc_ctx;
115 };
116 
117 uint8_t ff_sbc_crc8(const AVCRC *crc_ctx, const uint8_t *data, size_t len);
118 void ff_sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8]);
119 
120 #endif /* AVCODEC_SBC_H */
121