http://www.cnblogs.com/qq78292959/archive/2011/05/25/2076622.html
今天自己总结一下工程里的实现一个在线的音频播放器。。。
第一步呢。。先初始化AudioSession。为了实现中断的控制和后台，锁屏的播放状态
- (id)initsession {
AudioSessionInitialize (NULL, NULL, interruptionListenerCallback, self);
UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;//采用后台和锁屏时仍继续播放的模式;
AudioSessionSetProperty (kAudioSessionProperty_AudioCategory, sizeof (sessionCategory), &sessionCategory);
UInt32 doSetProperty = 0;
AudioSessionSetProperty (kAudioSessionProperty_OverrideCategoryMixWithOthers,sizeof (doSetProperty),&doSetProperty);
AudioSessionSetActive (true);//激活AudioSession
return self;
}
void interruptionListenerCallback (void *inUserData, UInt32 interruptionState) {
AudioPlayer *player = (AudioPlayer*)inUserData;
if (interruptionState == kAudioSessionBeginInterruption) {
//使音乐暂停
AudioWrapper * ad = [AudioWrapper sharedAudioWrapperElement];
[ad pause];
}
else if (interruptionState == kAudioSessionEndInterruption ) {
OSStatus rc = AudioSessionSetActive(true);
if (rc) {
NSLog(@"AudioSessionSetActive(true) returned %d", rc);
}
//使音乐恢复播放
AudioWrapper * ad = [AudioWrapper sharedAudioWrapperElement];
[ad resume];
}
}
第二步呢。。。为了接受在线过来的数据要使用媒体流功能，设置，最后解析NSData成为音频Buffer数据。。
先打开流媒体功能：
error = AudioFileStreamOpen(
(void*)self,
&AudioFileStreamPropertyListenerProc, //监听设置变化
&AudioFileStreamPacketsProc, //数据解析后的接收函数
0,
&audio_file_stream);//媒体流的ID
void AudioFileStreamPropertyListenerProc(
void *inClientData,
AudioFileStreamID inAudioFileStream,
AudioFileStreamPropertyID inPropertyID,
UInt32 *ioFlags)
{
#ifdef KXT_DEBUG
[ZPub LogTalk:@"AudioFileStreamPropertyListenerProc"];
#endif
;
}
void AudioFileStreamPacketsProc(
void *inClientData,
UInt32 inNumberBytes,
UInt32 inNumberPackets,
const void *inInputData,
AudioStreamPacketDescription *inPacketDescriptions) {
[(AudioPlayer*)inClientData newAudioData:inInputData bytes:inNumberBytes packets:inNumberPackets packetDescriptions:inPacketDescriptions];//自己开始整理解析后的数据
}
然后再把NSData传给×××解析：
error = AudioFileStreamParseBytes(
audio_file_stream,//在这时，媒体流文件ID被生成
datalen,
[data bytes],
kAudioFileStreamProperty_FileFormat);
这样解码后的数据自动会被发送到AudioFileStreamPacketsProc接口里。。
第三步;准备Buffer数据（mAudioData（所有的Data），mAudioDataByteSize数据的大小，num_packets多少包，packet_descriptions包的描述）
- (id)initWithData:(NSData*)_data packets:(UInt32)_num_packets packetDescriptions:(const AudioStreamPacketDescription*)_packet_descriptions {
if(!_data)
return nil;
if(!_packet_descriptions)
return nil;
self = [super init];
if(!self)
return nil;
self.data = _data;
num_packets = _num_packets;
packet_descriptions = malloc(num_packets * sizeof(AudioStreamPacketDescription));
memcpy((void*)packet_descriptions, (const void*)_packet_descriptions, num_packets * sizeof(AudioStreamPacketDescription));
return self;
}
第四步如果没有播放队列就创建播放队列。。。
UInt32 formatListSize;
Boolean b;//拿媒体流文件ID申请它的音乐格式结构信息
AudioFileStreamGetPropertyInfo(audio_file_stream,
kAudioFileStreamProperty_FormatList,
&formatListSize,
&b);
// now get the format data得到音乐格式信息
NSMutableData *listData = [NSMutableData dataWithLength:formatListSize];
OSStatus status = AudioFileStreamGetProperty(audio_file_stream,
kAudioFileStreamProperty_FormatList,
&formatListSize,
[listData mutableBytes]);
AudioFormatListItem *formatList = [listData mutableBytes];
// The formatList property isn't always supported, so an error isn't unexpected here.
// Therefore, we won't call VERIFY_STATUS on this status code.
if (status == noErr) {
// now see which format this device supports best
UInt32 chosen;
UInt32 chosenSize = sizeof(UInt32);
int formatCount = formatListSize/sizeof(AudioFormatListItem);
status = AudioFormatGetProperty ('fpfl',
formatListSize,
formatList,
&chosenSize,
&chosen);
if (status == noErr) {
audio_format = formatList[chosen].mASBD;//获取到具体的音乐格式（用于创建更好的播放队列）
} else {
// the docs tell us to grab the last in the list because it's most compatible
audio_format = formatList[formatCount - 1].mASBD;
}
} else {
// fall back to the stream's DataFormat
UInt32 audio_format_size = sizeof(AudioStreamBasicDescription);
error = AudioFileStreamGetProperty(audio_file_stream,
kAudioFileStreamProperty_DataFormat,
&audio_format_size,
&audio_format);
if(error){
[buffer release];
return;
}
}
Float32 outValue ;
AudioQueueGetParameter(audio_queue,kAudioQueueDeviceProperty_NumberChannels,&outValue) ;
if(![self createAudioQueue]){
[buffer release];
return;
}
}
- (BOOL)createAudioQueue {
error = AudioQueueNewOutput(&audio_format, &MyAudioQueueOutputCallback, (void*)self, [[NSRunLoop currentRunLoop] getCFRunLoop], kCFRunLoopCommonModes, 0, &audio_queue);
}
最后。将准备好的buffer放到已创建的播放队列里就播放了。
[buffer enqueueOnQueue:audio_queue];
- (void)enqueueOnQueue:(AudioQueueRef)queue {
AudioQueueBufferRef buffer;
error = AudioQueueAllocateBuffer(queue, [data length], &buffer);
if(error) {
[super dealloc];
return;
}
buffer->mAudioDataByteSize = [data length];
memcpy((char*)buffer->mAudioData, [data bytes], [data length]);
error = AudioQueueEnqueueBuffer(queue, buffer, num_packets, packet_descriptions);
if(error) {
[ZPub LogTalk:[NSString stringWithFormat:@"AudioQueueEnqueueBuffer failed with %d", (int)error]];
return;
}
}