sbc子带压缩编解码算法C语言版本

/* * * Bluetooth low-complexity, subband codec (SBC) library * * Copyright (C) 2004-2007 Marcel Holtmann <marcel@holtmann.org> * Copyright (C) 2004-2005 Henryk Ploetz <henryk@ploetzli.ch> * Copyright (C) 2005-2006 Brad Midgley <bmidgley@xmission.com> * * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * */ /* todo items: use a log2 table for byte integer scale factors calculation (sum log2 results for high and low bytes) fill bitpool by 16 bits instead of one at a time in bits allocation/bitpool generation port to the dsp */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include <stdio.h> #include <errno.h> #include <stdint.h> #include <malloc.h> #include <string.h> #include <stdlib.h> #include <sys/types.h> #include "sbc_math.h" #include "sbc_tables.h" #include "sbc.h" #define SBC_SYNCWORD 0x9C /* sampling frequency */ #define SBC_FS_16 0x00 #define SBC_FS_32 0x01 #define SBC_FS_44 0x02 #define SBC_FS_48 0x03 /* nrof_blocks */ #define SBC_NB_4 0x00 #define SBC_NB_8 0x01 #define SBC_NB_12 0x02 #define SBC_NB_16 0x03 /* channel mode */ #define SBC_CM_MONO 0x00 #define SBC_CM_DUAL_CHANNEL 0x01 #define SBC_CM_STEREO 0x02 #define SBC_CM_JOINT_STEREO 0x03 /* allocation mode */ #define SBC_AM_LOUDNESS 0x00 #define SBC_AM_SNR 0x01 /* subbands */ #define SBC_SB_4 0x00 #define SBC_SB_8 0x01 /* This structure contains an unpacked SBC frame. Yes, there is probably quite some unused space herein */ struct sbc_frame { uint16_t sampling_frequency; /* in kHz */ uint8_t blocks; enum { MONO = SBC_CM_MONO, DUAL_CHANNEL = SBC_CM_DUAL_CHANNEL, STEREO = SBC_CM_STEREO, JOINT_STEREO = SBC_CM_JOINT_STEREO } channel_mode; uint8_t channels; enum { LOUDNESS = SBC_AM_LOUDNESS, SNR = SBC_AM_SNR } allocation_method; uint8_t subbands; uint8_t bitpool; uint8_t codesize; uint8_t length; /* bit number x set means joint stereo has been used in subband x */ uint8_t join; /* only the lower 4 bits of every element are to be used */ uint8_t scale_factor[2][8]; /* raw integer subband samples in the frame */ uint16_t audio_sample[16][2][8]; int32_t sb_sample_f[16][2][8]; int32_t sb_sample[16][2][8]; /* modified subband samples */ int16_t pcm_sample[2][16*8]; /* original pcm audio samples */ }; struct sbc_decoder_state { int subbands; int32_t V[2][170]; int offset[2][16]; }; struct sbc_encoder_state { int subbands; int32_t X[2][80]; }; /* * Calculates the CRC-8 of the first len bits in data */ static const uint8_t crc_table[256] = { 0x00, 0x1D, 0x3A, 0x27, 0x74, 0x69, 0x4E, 0x53, 0xE8, 0xF5, 0xD2, 0xCF, 0x9C, 0x81, 0xA6, 0xBB, 0xCD, 0xD0, 0xF7, 0xEA, 0xB9, 0xA4, 0x83, 0x9E, 0x25, 0x38, 0x1F, 0x02, 0x51, 0x4C, 0x6B, 0x76, 0x87, 0x9A, 0xBD, 0xA0, 0xF3, 0xEE, 0xC9, 0xD4, 0x6F, 0x72, 0x55, 0x48, 0x1B, 0x06, 0x21, 0x3C, 0x4A, 0x57, 0x70, 0x6D, 0x3E, 0x23, 0x04, 0x19, 0xA2, 0xBF, 0x98, 0x85, 0xD6, 0xCB, 0xEC, 0xF1, 0x13, 0x0E, 0x29, 0x34, 0x67, 0x7A, 0x5D, 0x40, 0xFB, 0xE6, 0xC1, 0xDC, 0x8F, 0x92, 0xB5, 0xA8, 0xDE, 0xC3, 0xE4, 0xF9, 0xAA, 0xB7, 0x90, 0x8D, 0x36, 0x2B, 0x0C, 0x11, 0x42, 0x5F, 0x78, 0x65, 0x94, 0x89, 0xAE, 0xB3, 0xE0, 0xFD, 0xDA, 0xC7, 0x7C, 0x61, 0x46, 0x5B, 0x08, 0x15, 0x32, 0x2F, 0x59, 0x44, 0x63, 0x7E, 0x2D, 0x30, 0x17, 0x0A, 0xB1, 0xAC, 0x8B, 0x96, 0xC5, 0xD8, 0xFF, 0xE2, 0x26, 0x3B, 0x1C, 0x01, 0x52, 0x4F, 0x68, 0x75, 0xCE, 0xD3, 0xF4, 0xE9, 0xBA, 0xA7, 0x80, 0x9D, 0xEB, 0xF6, 0xD1, 0xCC, 0x9F, 0x82, 0xA5, 0xB8, 0x03, 0x1E, 0x39, 0x24, 0x77, 0x6A, 0x4D, 0x50, 0xA1, 0xBC, 0x9B, 0x86, 0xD5, 0xC8, 0xEF, 0xF2, 0x49, 0x54, 0x73, 0x6E, 0x3D, 0x20, 0x07, 0x1A, 0x6C, 0x71, 0x56, 0x4B, 0x18, 0x05, 0x22, 0x3F, 0x84, 0x99, 0xBE, 0xA3, 0xF0, 0xED, 0xCA, 0xD7, 0x35, 0x28, 0x0F, 0x12, 0x41, 0x5C, 0x7B, 0x66, 0xDD, 0xC0, 0xE7, 0xFA, 0xA9, 0xB4, 0x93, 0x8E, 0xF8, 0xE5, 0xC2, 0xDF, 0x8C, 0x91, 0xB6, 0xAB, 0x10, 0x0D, 0x2A, 0x37, 0x64, 0x79, 0x5E, 0x43, 0xB2, 0xAF, 0x88, 0x95, 0xC6, 0xDB, 0xFC, 0xE1, 0x5A, 0x47, 0x60, 0x7D, 0x2E, 0x33, 0x14, 0x09, 0x7F, 0x62, 0x45, 0x58, 0x0B, 0x16, 0x31, 0x2C, 0x97, 0x8A, 0xAD, 0xB0, 0xE3, 0xFE, 0xD9, 0xC4 }; static uint8_t sbc_crc8(const uint8_t *data, size_t len) { uint8_t crc = 0x0f; size_t i; uint8_t octet; for (i = 0; i < len / 8; i++) crc = crc_table[crc ^ data[i]]; octet = data[i]; for (i = 0; i < len % 8; i++) { char bit = ((octet ^ crc) & 0x80) >> 7; crc = ((crc & 0x7f) << 1) ^ (bit ? 0x1d : 0); octet = octet << 1; } return crc; } /* * Code straight from the spec to calculate the bits array * Takes a pointer to the frame in question, a pointer to the bits array and * the sampling frequency (as 2 bit integer) */ static void sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8], uint8_t sf) { if (frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL) { int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice; int ch, sb; for (ch = 0; ch < frame->channels; ch++) { max_bitneed = 0; if (frame->allocation_method == SNR) { for (sb = 0; sb < frame->subbands; sb++) { bitneed[ch][sb] = frame->scale_factor[ch][sb]; if (bitneed[ch][sb] > max_bitneed) max_bitneed = bitneed[ch][sb]; } } else { for (sb = 0; sb < frame->subbands; sb++) { if (frame->scale_factor[ch][sb] == 0) bitneed[ch][sb] = -5; else { if (frame->subbands == 4)//subband is 4 loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb]; else//subband is 8 loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb]; if (loudness > 0) bitneed[ch][sb] = loudness / 2; else bitneed[ch][sb] = loudness; } if (bitneed[ch][sb] > max_bitneed) max_bitneed = bitneed[ch][sb]; } } bitcount = 0; slicecount = 0; bitslice = max_bitneed + 1; do { bitslice--; bitcount += slicecount; slicecount = 0; for (sb = 0; sb < frame->subbands; sb++) { if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16)) slicecount++; else if (bitneed[ch][sb] == bitslice + 1) slicecount += 2; } } while (bitcount + slicecount < frame->bitpool); if (bitcount + slicecount == frame->bitpool) { bitcount += slicecount; bitslice--; } for (sb = 0; sb < frame->subbands; sb++) { if (bitneed[ch][sb] < bitslice + 2) bits[ch][sb] = 0; else { bits[ch][sb] = bitneed[ch][sb] - bitslice; if (bits[ch][sb] > 16) bits[ch][sb] = 16; } } for (sb = 0; bitcount < frame->bitpool && sb < frame->subbands; sb++) { if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) { bits[ch][sb]++; bitcount++; } else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) { bits[ch][sb] = 2; bitcount += 2; } } for (sb = 0; bitcount < frame->bitpool && sb < frame->subbands; sb++) { if (bits[ch][sb] < 16) { bits[ch][sb]++; bitcount++; } } } } else if (frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO) { int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice; int ch, sb; max_bitneed = 0; if (frame->allocation_method == SNR) { for (ch = 0; ch < 2; ch++) { for (sb = 0; sb < frame->subbands; sb++) { bitneed[ch][s