音频队列接口可以处理40ms音频帧吗？

Question

我试图在40ms的段中录制音频。 音频队列接口能处理40ms音频帧吗？ 如果'是'，那么我们该如何实现呢？

谢谢。

Answer 1

是，其可能的，你需要设置配置AudioQueue因此，

基本上AudioQueue缓冲区大小，具有40ms的进行设置，因此这将是左右，

int AQRecorder::ComputeRecordBufferSize(const AudioStreamBasicDescription *format, float seconds) 
{ 
    int packets, frames, bytes = 0; 
    try { 
     frames = (int)ceil(seconds * format->mSampleRate); 

     if (format->mBytesPerFrame > 0) 
      bytes = frames * format->mBytesPerFrame; 
     else { 
      UInt32 maxPacketSize; 
      if (format->mBytesPerPacket > 0) 
       maxPacketSize = format->mBytesPerPacket; // constant packet size 
      else { 
       UInt32 propertySize = sizeof(maxPacketSize); 
       XThrowIfError(AudioQueueGetProperty(mQueue, kAudioQueueProperty_MaximumOutputPacketSize, &maxPacketSize, 
                &propertySize), "couldn't get queue's maximum output packet size"); 
      } 
      if (format->mFramesPerPacket > 0) 
       packets = frames/format->mFramesPerPacket; 
      else 
       packets = frames; // worst-case scenario: 1 frame in a packet 
      if (packets == 0)  // sanity check 
       packets = 1; 
      bytes = packets * maxPacketSize; 
     } 
    } catch (CAXException e) { 
     char buf[256]; 
     return 0; 
    } 
    return bytes; 
} 

，并设置格式，

void AQRecorder::SetupAudioFormat(UInt32 inFormatID) 
{ 
    AudioStreamBasicDescription sRecordFormat; 
    FillOutASBDForLPCM (sRecordFormat, 
         SAMPLING_RATE, 
         1, 
         8*BYTES_PER_PACKET, 
         8*BYTES_PER_PACKET, 
         false, 
         false 
         ); 
    memset(&mRecordFormat, 0, sizeof(mRecordFormat)); 

    mRecordFormat.SetFrom(sRecordFormat); 
} 

我的情况，这些宏的值，

#define SAMPLING_RATE 16000 
#define kNumberRecordBuffers 3 
#define BYTES_PER_PACKET 2