音頻隊列-音頻採集

//
//  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 //隊列緩衝個數
#define MIN_SIZE_PER_FRAME 1000 //每幀最小數據長度
@interface AudioQueueCapture()
{
    
    AudioQueueRef audioQueue;//音頻播放隊列
    AudioQueueBufferRef    audioQueueBuffer[QUEUE_BUFFER_SIZE];//音頻緩存
    AudioStreamBasicDescription audioDescription;//音頻參數
}
@end
@implementation AudioQueueCapture

- (instancetype)init
{
    if (self=[super init]) {
        
        audioDescription.mSampleRate = 8000;//採樣率
        audioDescription.mFormatID = kAudioFormatLinearPCM;
        audioDescription.mFormatFlags = kLinearPCMFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
        audioDescription.mChannelsPerFrame = 1;///單聲道 每一幀數據包含的通道數
        audioDescription.mFramesPerPacket = 1;//每一個包數據的樣本幀的數量
        audioDescription.mBitsPerChannel = 16;//每一個採樣點16bit量化 每一幀數據的每個通道的採樣位的數量
        audioDescription.mBytesPerPacket = 2; // 每一個包數據的字節數量
        audioDescription.mBytesPerFrame = 2;//單幀包含的字節數據
        
    }
    return self;
}


- (void)stop
{
    if (audioQueue) {
        AudioQueueStop(audioQueue, YES);
        AudioQueueDispose(audioQueue, YES);
        audioQueue = NULL;
    }
}
- (void)start
{
    // 建立音頻輸入隊列
    if (AudioQueueNewInput(&audioDescription, audioQueueInputCallback, (__bridge void * _Nullable)(self), NULL, NULL, 0, &audioQueue) != noErr){
        return;
    }
    for (int i = 0; i < QUEUE_BUFFER_SIZE; i++) {
         //請求音頻隊列對象來分配一個音頻隊列緩存。
        AudioQueueAllocateBuffer(audioQueue, MIN_SIZE_PER_FRAME, &audioQueueBuffer[i]);
         //給錄音或者回放音頻隊列的緩存中添加一個緩存數據
        AudioQueueEnqueueBuffer(audioQueue, audioQueueBuffer[i], 0, NULL);
    }
    if (audioQueue) {
         //開始錄音
        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