iphone利用AudioQueue播放音頻文件(mp3,aac,caf,wav等)

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在此分享出來，但願能幫助到真正須要的人，畢竟一我的的力量是有限的，仍是要共同窗習、共同進步。
1.playAudio.h
聲明瞭一個Objective-C類
//
//  playAudio.h
//  ffmpegPlayAudio
//
//  Created by infomedia  xuanyuanchen on 12-3-26.
//  Copyright (c) 2012年 xuanyuanchen. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <AudioToolbox/AudioToolbox.h>
#import <AudioToolbox/AudioFile.h>
#define NUM_BUFFERS 3

@interface playAudio : NSObject{
    //播放音頻文件ID
    AudioFileID audioFile;
    //音頻流描述對象
    AudioStreamBasicDescription dataFormat;
    //音頻隊列
    AudioQueueRef queue;
    SInt64 packetIndex;
    UInt32 numPacketsToRead;
    UInt32 bufferByteSize;
    AudioStreamPacketDescription *packetDescs;
    AudioQueueBufferRef buffers[NUM_BUFFERS];
}

//定義隊列爲實例屬性
@property AudioQueueRef queue;
//播放方法定義
-(id)initWithAudio:(NSString *) path;
//定義緩存數據讀取方法
-(void) audioQueueOutputWithQueue:(AudioQueueRef)audioQueue
                      queueBuffer:(AudioQueueBufferRef)audioQueueBuffer;
-(UInt32)readPacketsIntoBuffer:(AudioQueueBufferRef)buffer;
//定義回調(Callback)函數
static void BufferCallack(void *inUserData,AudioQueueRef inAQ,
                          AudioQueueBufferRef buffer);

@end

2.playAudio.m
playAudio的實現
//
//  playAudio.m
//  ffmpegPlayAudio
//
//  Created by infomedia  infomedia on 12-3-26.
//  Copyright (c) 2012年 infomedia. All rights reserved.
//

#import "playAudio.h"
//實際測試中發現，這個gBufferSizeBytes=0x10000;對於壓縮的音頻格式(mp3/aac等)沒有任何問題，可是若是輸入的音頻 文件格式是wav，會出現只播放幾秒便暫停的現象；而手機又不可能去申請更大的內存去處理wav文件，不知到你們能有什麼好的方法給點建議

static UInt32 gBufferSizeBytes=0x10000;//It muse be pow(2,x)
@implementation playAudio

@synthesize queue;

//回調函數(Callback)的實現
static void BufferCallback(void *inUserData,AudioQueueRef inAQ,
                           AudioQueueBufferRef buffer){
    playAudio* player=(__bridge playAudio*)inUserData;
    [player audioQueueOutputWithQueue:inAQ queueBuffer:buffer];
}

//緩存數據讀取方法的實現
-(void) audioQueueOutputWithQueue:(AudioQueueRef)audioQueue queueBuffer:(AudioQueueBufferRef)audioQueueBuffer{
    OSStatus status;
   
    //讀取包數據www.2cto.com
    UInt32 numBytes;
    UInt32 numPackets=numPacketsToRead;
    status = AudioFileReadPackets(audioFile, NO, &numBytes, packetDescs, packetIndex,&numPackets, audioQueueBuffer->mAudioData);
   
    //成功讀取時
    if (numPackets>0) {
        //將緩衝的容量設置爲與讀取的音頻數據同樣大小(確保內存空間)
        audioQueueBuffer->mAudioDataByteSize=numBytes;
        //完成給隊列配置緩存的處理
        status = AudioQueueEnqueueBuffer(audioQueue, audioQueueBuffer, numPackets, packetDescs);
        //移動包的位置
        packetIndex += numPackets;
    }
}

//音頻播放的初始化、實現
//在ViewController中聲明一個PlayAudio對象，並用下面的方法來初始化
//self.audio=[[playAudioalloc]initWithAudio:@"/Users/xuanyuanchen/audio/daolang.mp3"];

-(id) initWithAudio:(NSString *)path{
    if (!(self=[super init])) return nil;
    UInt32 size,maxPacketSize;
    char *cookie;
    int i;
    OSStatus status;
   
    //打開音頻文件
    status=AudioFileOpenURL((CFURLRef)[NSURL fileURLWithPath:path], kAudioFileReadPermission, 0, &audioFile);
    if (status != noErr) {
        //錯誤處理
        NSLog(@"*** Error *** PlayAudio - play:Path: could not open audio file. Path given was: %@", path);
        return nil;
    }
   
    for (int i=0; i<NUM_BUFFERS; i++) {
        AudioQueueEnqueueBuffer(queue, buffers[i], 0, nil);
    }
   
    //取得音頻數據格式
    size = sizeof(dataFormat);
    AudioFileGetProperty(audioFile, kAudioFilePropertyDataFormat, &size, &dataFormat);
   
    //建立播放用的音頻隊列
    AudioQueueNewOutput(&dataFormat, BufferCallback, self,
                        nil, nil, 0, &queue);
    //計算單位時間包含的包數
    if (dataFormat.mBytesPerPacket==0 || dataFormat.mFramesPerPacket==0) {
        size=sizeof(maxPacketSize);
        AudioFileGetProperty(audioFile, kAudioFilePropertyPacketSizeUpperBound, &size, &maxPacketSize);
        if (maxPacketSize > gBufferSizeBytes) {
            maxPacketSize= gBufferSizeBytes;
        }
        //算出單位時間內含有的包數
        numPacketsToRead = gBufferSizeBytes/maxPacketSize;
        packetDescs=malloc(sizeof(AudioStreamPacketDescription)*numPacketsToRead);
    }else {
        numPacketsToRead= gBufferSizeBytes/dataFormat.mBytesPerPacket;
        packetDescs=nil;
    }
   
    //設置Magic Cookie，參見第二十七章的相關介紹
    AudioFileGetProperty(audioFile, kAudioFilePropertyMagicCookieData, &size, nil);
    if (size >0) {
        cookie=malloc(sizeof(char)*size);
        AudioFileGetProperty(audioFile, kAudioFilePropertyMagicCookieData, &size, cookie);
        AudioQueueSetProperty(queue, kAudioQueueProperty_MagicCookie, cookie, size);
    }
   
    //建立並分配緩衝空間
    packetIndex=0;
    for (i=0; i<NUM_BUFFERS; i++) {
        AudioQueueAllocateBuffer(queue, gBufferSizeBytes, &buffers[i]);
        //讀取包數據
        if ([self readPacketsIntoBuffer:buffers[i]]==1) {
            break;
        }
    }
   
    Float32 gain=1.0;
    //設置音量
    AudioQueueSetParameter(queue, kAudioQueueParam_Volume, gain);
    //隊列處理開始，此後系統開始自動調用回調(Callback)函數
    AudioQueueStart(queue, nil);
    return self;
}

-(UInt32)readPacketsIntoBuffer:(AudioQueueBufferRef)buffer {
    UInt32 numBytes,numPackets;
   
    //從文件中接受數據並保存到緩存(buffer)中
    numPackets = numPacketsToRead;
    AudioFileReadPackets(audioFile, NO, &numBytes, packetDescs, packetIndex, &numPackets, buffer->mAudioData);
    if(numPackets >0){
        buffer->mAudioDataByteSize=numBytes;
        AudioQueueEnqueueBuffer(queue, buffer, (packetDescs ? numPackets : 0), packetDescs);
        packetIndex += numPackets;
    }
    else{
        return 1;//意味着咱們沒有讀到任何的包
    }
    return 0;//0表明正常的退出
}
@end

這裏只是實現了最簡單的經過AudioQueue播放音頻文件。代碼寫的比較簡潔，相信搭建應該都能理解吧。

摘自http://www.2cto.com/kf/201204/126390.html