USB语音双缓冲技术 示例
时间: 2023-07-07 12:07:06 浏览: 64
USB语音双缓冲技术是一种用于实现高质量音频传输的技术。它通过使用两个缓冲区来减少音频数据传输时的延迟和音频数据的丢失。
下面是一个示例:
```c
#define SAMPLE_RATE_HZ 16000 // 采样率
#define BYTES_PER_SAMPLE 2 // 每个采样点占用的字节数
#define BUFFER_SIZE_MS 10 // 缓冲区大小(毫秒)
#define BUFFER_SIZE (SAMPLE_RATE_HZ * BYTES_PER_SAMPLE * BUFFER_SIZE_MS / 1000) // 缓冲区大小(字节数)
/* 双缓冲区结构体 */
typedef struct {
uint8_t buffer[BUFFER_SIZE]; // 缓冲区数据
uint32_t write_offset; // 当前写入位置
uint32_t read_offset; // 当前读取位置
} double_buffer_t;
/* USB音频输入回调函数 */
void usb_audio_input_callback(uint8_t *data, uint32_t size) {
static double_buffer_t buffer1 = {0};
static double_buffer_t buffer2 = {0};
static double_buffer_t *current_buffer = &buffer1;
static double_buffer_t *next_buffer = &buffer2;
/* 将数据写入下一个缓冲区 */
memcpy(next_buffer->buffer + next_buffer->write_offset, data, size);
next_buffer->write_offset += size;
/* 如果下一个缓冲区已满,切换当前缓冲区 */
if (next_buffer->write_offset >= BUFFER_SIZE) {
current_buffer = next_buffer;
next_buffer = (next_buffer == &buffer1) ? &buffer2 : &buffer1;
}
}
/* 读取音频数据 */
uint32_t read_audio_data(uint8_t *data, uint32_t size) {
static double_buffer_t buffer1 = {0};
static double_buffer_t buffer2 = {0};
static double_buffer_t *current_buffer = &buffer1;
static double_buffer_t *next_buffer = &buffer2;
uint32_t bytes_read = 0;
/* 从当前缓冲区中读取数据 */
while (bytes_read < size) {
uint32_t bytes_to_read = size - bytes_read;
uint32_t bytes_available = current_buffer->write_offset - current_buffer->read_offset;
if (bytes_to_read > bytes_available) {
bytes_to_read = bytes_available;
}
memcpy(data + bytes_read, current_buffer->buffer + current_buffer->read_offset, bytes_to_read);
current_buffer->read_offset += bytes_to_read;
bytes_read += bytes_to_read;
/* 如果当前缓冲区已空,切换下一个缓冲区 */
if (current_buffer->read_offset >= current_buffer->write_offset) {
current_buffer->read_offset = 0;
current_buffer->write_offset = 0;
next_buffer->read_offset = 0;
next_buffer->write_offset = 0;
current_buffer = next_buffer;
next_buffer = (next_buffer == &buffer1) ? &buffer2 : &buffer1;
}
}
return bytes_read;
}
```
在上面的示例中,我们定义了一个双缓冲区结构体,其中包含两个缓冲区:当前缓冲区和下一个缓冲区。USB音频输入回调函数会将音频数据写入下一个缓冲区,并在下一个缓冲区已满时切换当前缓冲区。我们还定义了一个读取音频数据的函数,该函数从当前缓冲区中读取数据,并在当前缓冲区已空时切换下一个缓冲区。
通过使用USB语音双缓冲技术,我们可以实现高质量的音频传输,并避免音频数据的延迟和丢失。