/* * *  Bluetooth low-complexity, subband codec (SBC) library * *  Copyright (C) 2004-2008  Marcel Holtmann <marcel@holtmann.org> *  Copyright (C) 2004-2005  Henryk Ploetz <henryk@ploetzli.ch> *  Copyright (C) 2005-2008  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 <string.h>#include <stdlib.h>#include <sys/types.h>#include "sbc_math.h"#include "sbc_tables.h"#include "sbc.h"#define SBC_SYNCWORD	0x9C/* This structure contains an unpacked SBC frame.   Yes, there is probably quite some unused space herein */struct sbc_frame {	uint8_t frequency;	uint8_t block_mode;	uint8_t blocks;	enum {		MONO		= SBC_MODE_MONO,		DUAL_CHANNEL	= SBC_MODE_DUAL_CHANNEL,		STEREO		= SBC_MODE_STEREO,		JOINT_STEREO	= SBC_MODE_JOINT_STEREO	} mode;	uint8_t channels;	enum {		LOUDNESS	= SBC_AM_LOUDNESS,		SNR		= SBC_AM_SNR	} allocation;	uint8_t subband_mode;	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 joint;	/* 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 */	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;	int position[2];	int32_t X[2][160];};/* * 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 = frame->frequency;	if (frame->mode == MONO || frame->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 == 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)							loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];						else							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->mode == STEREO || frame->mode == JOINT_STEREO) {		int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;		int ch, sb;		max_bitneed = 0;		if (frame->allocation == SNR) {			for (ch = 0; ch < 2; ch++) {				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 (ch = 0; ch < 2; ch++) {				for (sb = 0; sb < frame->subbands; sb++) {					if (frame->scale_factor[ch][sb] == 0)						bitneed[ch][sb] = -5;					else {						if (frame->subbands == 4)							loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];						else							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 (ch = 0; ch < 2; ch++) {				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 (ch = 0; ch < 2; ch++) {			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;				}			}		}		ch = 0;		sb = 0;		while (bitcount < frame->bitpool) {			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;			}			if (ch == 1) {				ch = 0;				sb++;				if (sb >= frame->subbands) break;			} else				ch = 1;		}		ch = 0;		sb = 0;		while (bitcount < frame->bitpool) {			if (bits[ch][sb] < 16) {				bits[ch][sb]++;				bitcount++;			}			if (ch == 1) {				ch = 0;				sb++;				if (sb >= frame->subbands) break;			} else				ch = 1;		}	}}/* * Unpacks a SBC frame at the beginning of the stream in data, * which has at most len bytes into frame. * Returns the length in bytes of the packed frame, or a negative * value on error. The error codes are: * *  -1   Data stream too short *  -2   Sync byte incorrect *  -3   CRC8 incorrect *  -4   Bitpool value out of bounds */static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame,				size_t len){	int consumed;	/* Will copy the parts of the header that are relevant to crc	 * calculation here */	uint8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };	int crc_pos = 0;	int32_t temp;	int audio_sample;	int ch, sb, blk, bit;	/* channel, subband, block and bit standard				   counters */	int bits[2][8];		/* bits distribution */	uint32_t levels[2][8];	/* levels derived from that */	if (len < 4)		return -1;	if (data[0] != SBC_SYNCWORD)		return -2;	frame->frequency = (data[1] >> 6) & 0x03;	frame->block_mode = (data[1] >> 4) & 0x03;	switch (frame->block_mode) {	case SBC_BLK_4:		frame->blocks = 4;		break;	case SBC_BLK_8:		frame->blocks = 8;		break;	case SBC_BLK_12:		frame->blocks = 12;		break;	case SBC_BLK_16:		frame->blocks = 16;		break;	}	frame->mode = (data[1] >> 2) & 0x03;	switch (frame->mode) {	case MONO:		frame->channels = 1;		break;	case DUAL_CHANNEL:	/* fall-through */	case STEREO:	case JOINT_STEREO:		frame->channels = 2;		break;	}	frame->allocation = (data[1] >> 1) & 0x01;	frame->subband_mode = (data[1] & 0x01);	frame->subbands = frame->subband_mode ? 8 : 4;	frame->bitpool = data[2];	if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) &&			frame->bitpool > 16 * frame->subbands)		return -4;	if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) &&			frame->bitpool > 32 * frame->subbands)		return -4;	/* data[3] is crc, we're checking it later */	consumed = 32;	crc_header[0] = data[1];	crc_header[1] = data[2];	crc_pos = 16;	if (frame->mode == JOINT_STEREO) {		if (len * 8 < consumed + frame->subbands)			return -1;		frame->joint = 0x00;		for (sb = 0; sb < frame->subbands - 1; sb++)			frame->joint |= ((data[4] >> (7 - sb)) & 0x01) << sb;		if (frame->subbands == 4)			crc_header[crc_pos / 8] = data[4] & 0xf0;		else			crc_header[crc_pos / 8] = data[4];		consumed += frame->subbands;		crc_pos += frame->subbands;	}	if (len * 8 < consumed + (4 * frame->subbands * frame->channels))		return -1;	for (ch = 0; ch < frame->channels; ch++) {		for (sb = 0; sb < frame->subbands; sb++) {			/* FIXME assert(consumed % 4 == 0); */			frame->scale_factor[ch][sb] =				(data[consumed >> 3] >> (4 - (consumed & 0x7))) & 0x0F;			crc_header[crc_pos >> 3] |=				frame->scale_factor[ch][sb] << (4 - (crc_pos & 0x7));			consumed += 4;			crc_pos += 4;		}	}	if (data[3] != sbc_crc8(crc_header, crc_pos))		return -3;