iphone利用AudioQueue播放音频文件(mp3,aac,caf,wav等)

声明：转载请注明出处http://www.cnblogs.com/xuanyuanchen/最近在做iphone上的流媒体播放，需要用到播放音频流，参考了好多博客、网站，最终算是把这个比较难弄的问题解决了。这篇文章是播放音频文件的，我会专门用一篇文章来介绍如何用AudioQueue来播放raw pcm data，相信这是大多数ios开发同胞需要的吧。在此分享出来，希望能帮助到真正需要的人，毕竟一个人的力量是有限的，还是要共同学习、共同进步。1.playAudio.h声明了一个Objective-C类

//
//  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{
    //播放音频文件ID
    AudioFileID audioFile;
    //音频流描述对象
    AudioStreamBasicDescription dataFormat;
    //音频队列
    AudioQueueRef queue;
    SInt64 packetIndex;
    UInt32 numPacketsToRead;
    UInt32 bufferByteSize;
    AudioStreamPacketDescription *packetDescs;
    AudioQueueBufferRef buffers[NUM_BUFFERS];
}

//定义队列为实例属性
@property AudioQueueRef queue;
//播放方法定义
-(id)initWithAudio:(NSString *) path;
//定义缓存数据读取方法
-(void) audioQueueOutputWithQueue:(AudioQueueRef)audioQueue
                      queueBuffer:(AudioQueueBufferRef)audioQueueBuffer;
-(UInt32)readPacketsIntoBuffer:(AudioQueueBufferRef)buffer;
//定义回调(Callback)函数
static void BufferCallack(void *inUserData,AudioQueueRef inAQ,
                          AudioQueueBufferRef buffer);

@end

2.playAudio.mplayAudio的实现

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

#import "playAudio.h"

//实际测试中发现，这个gBufferSizeBytes=0x10000;对于压缩的音频格式(mp3/aac等)没有任何问题，但是如果输入的音频文件格式是wav，会出现只播放几秒便暂停的现象；而手机又不可能去申请更大的内存去处理wav文件，不知到大家能有什么好的方法给点建议

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

@implementation playAudio

@synthesize queue;

//回调函数(Callback)的实现
static void BufferCallback(void *inUserData,AudioQueueRef inAQ,
                           AudioQueueBufferRef buffer){
    playAudio* player=(__bridge playAudio*)inUserData;
    [player audioQueueOutputWithQueue:inAQ queueBuffer:buffer];
}

//缓存数据读取方法的实现
-(void) audioQueueOutputWithQueue:(AudioQueueRef)audioQueue queueBuffer:(AudioQueueBufferRef)audioQueueBuffer{
    OSStatus status;
    
    //读取包数据
    UInt32 numBytes;
    UInt32 numPackets=numPacketsToRead;
    status = AudioFileReadPackets(audioFile, NO, &numBytes, packetDescs, packetIndex,&numPackets, audioQueueBuffer->mAudioData);
    
    //成功读取时
    if (numPackets>0) {
        //将缓冲的容量设置为与读取的音频数据一样大小(确保内存空间)
        audioQueueBuffer->mAudioDataByteSize=numBytes;
        //完成给队列配置缓存的处理
        status = AudioQueueEnqueueBuffer(audioQueue, audioQueueBuffer, numPackets, packetDescs);
        //移动包的位置
        packetIndex += numPackets;
    }
}

//音频播放的初始化、实现

//在ViewController中声明一个PlayAudio对象，并用下面的方法来初始化

//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;        //打开音频文件    status=AudioFileOpenURL((CFURLRef)[NSURL fileURLWithPath:path], kAudioFileReadPermission, 0, &audioFile);    if (status != noErr) {        //错误处理        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);    }        //取得音频数据格式    size = sizeof(dataFormat);    AudioFileGetProperty(audioFile, kAudioFilePropertyDataFormat, &size, &dataFormat);        //创建播放用的音频队列    AudioQueueNewOutput(&dataFormat, BufferCallback, self,                        nil, nil, 0, &queue);    //计算单位时间包含的包数    if (dataFormat.mBytesPerPacket==0 || dataFormat.mFramesPerPacket==0) {        size=sizeof(maxPacketSize);        AudioFileGetProperty(audioFile, kAudioFilePropertyPacketSizeUpperBound, &size, &maxPacketSize);        if (maxPacketSize > gBufferSizeBytes) {            maxPacketSize= gBufferSizeBytes;        }        //算出单位时间内含有的包数        numPacketsToRead = gBufferSizeBytes/maxPacketSize;        packetDescs=malloc(sizeof(AudioStreamPacketDescription)*numPacketsToRead);    }else {        numPacketsToRead= gBufferSizeBytes/dataFormat.mBytesPerPacket;        packetDescs=nil;    }        //设置Magic Cookie，参见第二十七章的相关介绍    AudioFileGetProperty(audioFile, kAudioFilePropertyMagicCookieData, &size, nil);    if (size >0) {        cookie=malloc(sizeof(char)*size);        AudioFileGetProperty(audioFile, kAudioFilePropertyMagicCookieData, &size, cookie);        AudioQueueSetProperty(queue, kAudioQueueProperty_MagicCookie, cookie, size);    }        //创建并分配缓冲空间    packetIndex=0;    for (i=0; i<NUM_BUFFERS; i++) {        AudioQueueAllocateBuffer(queue, gBufferSizeBytes, &buffers[i]);        //读取包数据        if ([self readPacketsIntoBuffer:buffers[i]]==1) {            break;        }    }        Float32 gain=1.0;    //设置音量    AudioQueueSetParameter(queue, kAudioQueueParam_Volume, gain);    //队列处理开始，此后系统开始自动调用回调(Callback)函数    AudioQueueStart(queue, nil);    return self;}-(UInt32)readPacketsIntoBuffer:(AudioQueueBufferRef)buffer {    UInt32 numBytes,numPackets;        //从文件中接受数据并保存到缓存(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;//意味着我们没有读到任何的包    }    return 0;//0代表正常的退出}@end

这里只是实现了最简单的通过AudioQueue播放音频文件。代码写的比较简洁，相信搭建应该都能理解吧。