音频队列-音频采集

//
//  AudioCapture.m
//  live
//
//  Created by lujunjie on 2016/11/5.
//  Copyright © 2016年 lujunjie. All rights reserved.
//

#import "AudioQueueCapture.h"
#import <AudioToolbox/AudioToolbox.h>
#define QUEUE_BUFFER_SIZE 10 //队列缓冲个数
#define MIN_SIZE_PER_FRAME 1000 //每帧最小数据长度
@interface AudioQueueCapture()
{
    
    AudioQueueRef audioQueue;//音频播放队列
    AudioQueueBufferRef    audioQueueBuffer[QUEUE_BUFFER_SIZE];//音频缓存
    AudioStreamBasicDescription audioDescription;//音频参数
}
@end
@implementation AudioQueueCapture

- (instancetype)init
{
    if (self=[super init]) {
        
        audioDescription.mSampleRate = 8000;//采样率
        audioDescription.mFormatID = kAudioFormatLinearPCM;
        audioDescription.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
        audioDescription.mChannelsPerFrame = 1;///单声道 每一帧数据包含的通道数
        audioDescription.mFramesPerPacket = 1;//每个包数据的样本帧的数量
        audioDescription.mBitsPerChannel = 16;//每个采样点16bit量化 每一帧数据的每一个通道的采样位的数量
        audioDescription.mBytesPerPacket = 2; // 每个包数据的字节数量
        audioDescription.mBytesPerFrame = 2;//单帧包含的字节数据
        
    }
    return self;
}


- (void)stop
{
    if (audioQueue) {
        AudioQueueStop(audioQueue, YES);
        AudioQueueDispose(audioQueue, YES);
        audioQueue = NULL;
    }
}
- (void)start
{
    // 创建音频输入队列
    if (AudioQueueNewInput(&audioDescription, audioQueueInputCallback, (__bridge void * _Nullable)(self), NULL, NULL, 0, &audioQueue) != noErr){
        return;
    }
    for (int i = 0; i < QUEUE_BUFFER_SIZE; i++) {
         //请求音频队列对象来分配一个音频队列缓存。
        AudioQueueAllocateBuffer(audioQueue, MIN_SIZE_PER_FRAME, &audioQueueBuffer[i]);
         //给录音或者回放音频队列的缓存中添加一个缓存数据
        AudioQueueEnqueueBuffer(audioQueue, audioQueueBuffer[i], 0, NULL);
    }
    if (audioQueue) {
         //开始录音
        AudioQueueStart(audioQueue, NULL);
    }
}


void audioQueueInputCallback (void *inUserData,AudioQueueRef inoQueueRef, AudioQueueBufferRef inBuffer,const AudioTimeStamp *inStartTime, UInt32 inNumberPacketDescriptions, const AudioStreamPacketDescription *inPacketDescs) {
    
    AudioQueueCapture *self = (__bridge AudioQueueCapture *)inUserData;
    [self.delegate audioQueueCaptureData:inBuffer->mAudioData dataLength:inBuffer->mAudioDataBytesCapacity];
    AudioQueueEnqueueBuffer(inoQueueRef, inBuffer, 0, NULL);
}
- (void)dealloc {
    
    [self stop];
    self.delegate = nil;
    
}
@end