用c语言写一个sbc转pcm的算法
时间: 2023-03-21 12:00:28 浏览: 118
好的,以下是一个简单的用C语言实现的sbc转pcm算法:
```c
#include <stdint.h>
#include <stdbool.h>
#define SBC_FRAME_SIZE 64
void sbc_to_pcm(uint8_t *sbc_data, uint32_t sbc_len, int16_t *pcm_data, uint32_t *pcm_len) {
static const int16_t sbc_scale_factor[16] = {
0x0008, 0x000a, 0x000c, 0x000e,
0x0010, 0x0014, 0x0018, 0x001c,
0x0020, 0x0028, 0x0030, 0x0038,
0x0040, 0x0050, 0x0060, 0x0070
};
static const uint8_t sbc_bitpool_limits[2][16] = {
{ 16, 20, 24, 28, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224 },
{ 16, 20, 24, 28, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176 }
};
uint8_t *sbc_ptr = sbc_data;
uint8_t sbc_header;
uint8_t sbc_bitpool;
uint8_t sbc_channels;
uint8_t sbc_blocks;
uint8_t sbc_subbands;
uint8_t sbc_bit_allocation[SBC_FRAME_SIZE];
int16_t pcm_samples[SBC_FRAME_SIZE * 2];
uint32_t sbc_data_len = sbc_len;
uint32_t pcm_data_len = 0;
uint32_t frame_size;
while (sbc_data_len > 0) {
/* 解析SBC帧头 */
sbc_header = *sbc_ptr++;
sbc_bitpool = *sbc_ptr++;
sbc_channels = (sbc_header >> 4) & 0x03;
sbc_blocks = (sbc_header >> 2) & 0x03;
sbc_subbands = (sbc_header >> 1) & 0x01;
frame_size = sbc_header & 0x01 ? 53 : 64;
/* 计算每个采样点的比特数 */
uint8_t bit_alloc_size = (frame_size * sbc_channels * sbc_subbands + 7) / 8;
memcpy(sbc_bit_allocation, sbc_ptr, bit_alloc_size);
sbc_ptr += bit_alloc_size;
/* 解压缩采样点 */
for (uint32_t i = 0; i < frame_size; i++) {
for (uint32_t ch = 0; ch < sbc_channels; ch++) {
int16_t pcm_sample = 0;
uint8_t bits = sbc_bit_allocation[i * sbc_channels + ch];
if (bits == 0) {
pcm_samples[i * sbc_channels + ch] = 0;
continue;
}
for (uint32_t sb = 0; sb < sbc_subbands; sb++) {
uint8_t code = *sbc_ptr++;
int16_t sb_sample = (int16