C代码
• 数据类型
1.AudioFileStreamID 文件流
2.AudioQueueRef 播放队列
3.AudioStreamBasicDescription 格式化音频数据
4.AudioQueueBufferRef 数据缓冲
• 回调函数
1.AudioFileStream_PacketsProc 解析音频数据回调
2.AudioSessionInterruptionListener 音频会话被打断
3.AudioQueueOutputCallback 一个AudioQueueBufferRef播放完
• 主要函数
0.AudioSessionInitialize (NULL, NULL, AudioSessionInterruptionListener, self);
初始化音频会话
1.AudioFileStreamOpen(
(void*)self,
&AudioFileStreamPropertyListenerProc,
&AudioFileStreamPacketsProc,
0,
&audio_file_stream);
建立一个文件流AudioFileStreamID，传输解析的数据
2.AudioFileStreamParseBytes(
audio_file_stream,
datalen,
[data bytes],
kAudioFileStreamProperty_FileFormat);
解析音频数据
3.AudioQueueNewOutput(&audio_format, AudioQueueOutputCallback, (void*)self, [[NSRunLoop currentRunLoop] getCFRunLoop], kCFRunLoopCommonModes, 0, &audio_queue);
创建音频队列AudioQueueRef
4.AudioQueueAllocateBuffer(queue, [data length], &buffer);
创建音频缓冲数据AudioQueueBufferRef
5.AudioQueueEnqueueBuffer(queue, buffer, num_packets, packet_descriptions);
把缓冲数据排队加入到AudioQueueRef等待播放
6.AudioQueueStart(audio_queue, nil); 播放
7.AudioQueueStop(audio_queue, true);
AudioQueuePause(audio_queue); 停止、暂停
• 断点续传
2.playAudio.m
playAudio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。
如果有需要的朋友，我可以把源码传上来共搭建分享，其实这个工程也比较简单。