流媒体播放－在线音乐（1）

流播放文件即用AudioStream 和 AudioQueue 来播放文件。好处是可以快速的开始播放，减少读文件的过程，适合大文件特别是背景音乐的播放。坏处是一次只能播放一个文件，如果要换播放文件，中间需要一定的时间。但是因为iPhone的文件读取时间只有10秒，对于资源较大的文件，只能考虑这个方式了。下面我将分享一下我在这方面的一点经验：

1. 单个文件播放2. 在线文件播放

1. 单个文件播放 BOOL isPlaying;

AudioFileID audioFile;

AudioStreamBasicDescription dataFormat;

AudioStreamPacketDescription *packetDescs;

UInt64 packetIndex;

UInt32 numPacketsToRead;

BOOL repeat;

BOOL trackClosed;

BOOL trackEnded;

AudioQueueRef queue;

AudioQueueBufferRef buffers[NUM_QUEUE_BUFFERS];

以上是需要定义的为单独文件播放的所需要的元素。可以定义在类里面。

2. 在线文件播放

NSURL *url;

AudioFileStreamID audioFileStream; // the audio file stream parser

AudioStreamPacketDescription packetDescsQueue[kAQMaxPacketDescs]; // packet descriptions for enqueuing audio

CFReadStreamRef stream;

unsigned int fillBufferIndex; // the index of the audioQueueBuffer that is being filled

size_t bytesFilled; // how many bytes have been filled

size_t packetsFilled; // how many packets have been filled

bool inuse[kNumAQBufs]; // flags to indicate that a buffer is still in use

bool started; // flag to indicate that the queue has been started

bool failed; // flag to indicate an error occurred

bool discontinuous; // flag to trigger bug-avoidance

pthread_mutex_t mutex; // a mutex to protect the inuse flags

pthread_cond_t cond; // a condition varable for handling the inuse flags

pthread_mutex_t mutex2; // a mutex to protect the AudioQueue buffer

BOOL trackEnded;

AudioQueueRef queue;

AudioQueueBufferRef buffers[NUM_QUEUE_BUFFERS];

利用http1.1协议播放在线文件。以上是在线文件播放所需要的参数。

#define NUM_QUEUE_BUFFERS 3

#define kNumAQBufs 6 // number of audio queue buffers we allocate

#define kAQBufSize 32 * 1024 // number of bytes in each audio queue buffer

#define kAQMaxPacketDescs 512 // number of packet descriptions in our array

这里是定义的一些参数，NUM_QUEUE_BUFFERS 用于播放本地文件，而 kNumAQBufs 用于播放在线文件。

3. 本地文件初始化

- (id)initWithPath:(NSString*)path

{

UInt32 size, maxPacketSize;

char *cookie;

int i;

if (kxxxTrackActive)

{

NSLog(@"Other music is playing.");

return nil;

}

if (path == nil) return nil;

if(!(self = [super init])) return nil;

// try to open up the file using the specified path

if (noErr != AudioFileOpenURL((CFURLRef)[NSURL fileURLWithPath:path], 0x01, 0, &audioFile))

{

NSLog(@"File can not be opened!");

return nil;

}

// get the data format of the file

size = sizeof(dataFormat);

AudioFileGetProperty(audioFile, kAudioFilePropertyDataFormat, &size, &dataFormat);

// create a new playback queue using the specified data format and buffer callback

AudioQueueNewOutput(&dataFormat, BufferCallback, self, nil, nil, 0, &queue);

// calculate number of packets to read and allocate space for packet descriptions if needed

if (dataFormat.mBytesPerPacket == 0 || dataFormat.mFramesPerPacket == 0)

{

// Ask Core Audio to give us a conservative estimate of the largest packet

size = sizeof(maxPacketSize);

AudioFileGetProperty(audioFile, kAudioFilePropertyPacketSizeUpperBound, &size, &maxPacketSize);

if (maxPacketSize > kxxxBufferSizeBytes)

{

maxPacketSize = kxxxBufferSizeBytes;

NSLog(@"Size out of bounds!");

}

// calculate how many packs to read

numPacketsToRead = kxxxBufferSizeBytes / maxPacketSize;

// will need a packet description for each packet to allocate space accordingly

packetDescs = malloc(sizeof(AudioStreamPacketDescription) * numPacketsToRead);

}

else

{

// constant bitrate

numPacketsToRead = kxxxBufferSizeBytes / dataFormat.mBytesPerPacket;

// don't need packet descriptions for CBR data

packetDescs = nil;

}

// see if file uses a magic cookie (a magic cookie is meta data which some formats use)

AudioFileGetPropertyInfo(audioFile, kAudioFilePropertyMagicCookieData, &size, nil);

if (size > 0)

{

// copy the cookie data from the file into the audio queue

cookie = malloc(sizeof(char) * size);

AudioFileGetProperty(audioFile, kAudioFilePropertyMagicCookieData, &size, cookie);

AudioQueueSetProperty(queue, kAudioQueueProperty_MagicCookie, cookie, size);

free(cookie);

}

// we want to know when the playing state changes so we can properly dispose of the audio queue when it's done

AudioQueueAddPropertyListener(queue, kAudioQueueProperty_IsRunning, propertyListenerCallback, self);

// allocate and prime buffers with some data

packetIndex = 0;

for (i = 0; i < NUM_QUEUE_BUFFERS; i++)

{

AudioQueueAllocateBuffer(queue, kxxxBufferSizeBytes, &buffers);

if ([self readPacketsIntoBuffer:buffers] == 0)

{

// this might happen if the file was so short that it needed less buffers than we planned on using

break;

}

repeat = NO;

trackClosed = NO;

trackEnded = NO;

kxxxTrackActive = YES;

return self;

}

4. 在线文件初始化

- (id)initWithURL:(NSURL*)newUrl

{

self = [super init];

if (self != nil)

{

url = [newUrl retain];

}

return self;

}

算了，废话不多说了，直接上代码，等以后有时间了再逐一解释。

.h文件

#ifdef TARGET_OS_IPHONE

#import <UIKit/UIKit.h>

#else

#import <Cocoa/Cocoa.h>

#endif TARGET_OS_IPHONE

#import <AudioToolbox/AudioQueue.h>

#import <AudioToolbox/AudioFile.h>

#include <pthread.h>

#include <AudioToolbox/AudioToolbox.h>

#define NUM_QUEUE_BUFFERS 3

#define kNumAQBufs 6 // number of audio queue buffers we allocate

#define kAQBufSize 32 * 1024 // number of bytes in each audio queue buffer

#define kAQMaxPacketDescs 512 // number of packet descriptions in our array

@interface xxxxx : NSObject {

NSURL *url;

BOOL isPlaying;

@public

AudioFileStreamID audioFileStream; // the audio file stream parser

AudioStreamPacketDescription packetDescsQueue[kAQMaxPacketDescs]; // packet descriptions for enqueuing audio

CFReadStreamRef stream;

unsigned int fillBufferIndex; // the index of the audioQueueBuffer that is being filled

size_t bytesFilled; // how many bytes have been filled

size_t packetsFilled; // how many packets have been filled

bool inuse[kNumAQBufs]; // flags to indicate that a buffer is still in use

bool started; // flag to indicate that the queue has been started

bool failed; // flag to indicate an error occurred

bool discontinuous; // flag to trigger bug-avoidance

pthread_mutex_t mutex; // a mutex to protect the inuse flags

pthread_cond_t cond; // a condition varable for handling the inuse flags

pthread_mutex_t mutex2; // a mutex to protect the AudioQueue buffer

AudioFileID audioFile;

AudioStreamBasicDescription dataFormat;

AudioStreamPacketDescription *packetDescs;

UInt64 packetIndex;

UInt32 numPacketsToRead;

BOOL repeat;

BOOL trackClosed;

BOOL trackEnded;

AudioQueueRef queue;

AudioQueueBufferRef buffers[NUM_QUEUE_BUFFERS];

}

@property BOOL isPlaying;

@property BOOL trackClosed;

- (id) initWithURL:(NSURL*) newURL;

- (id) initWithPath:(NSString*) path;

- (void) setGain:(Float32)gain;

- (void) setRepeat:(BOOL)yn;

- (void) setPlayingWhenAutoLock;

- (void) play;

- (void) playURL;

- (void) pause;

- (void) stopURL;

- (void) close;

extern NSString *xxxTrackFinishedPlayingNotification;

@end

.m文件

#import "xxxxx.h"

#import <CFNetwork/CFNetwork.h>

static UInt32 kxxxBufferSizeBytes = 0x10000; // 64k

static BOOL kxxxTrackActive = NO;

NSString *xxxTrackFinishedPlayingNotification = @"xxxTrackFinishedPlayingNotification";

#pragma mark -

#pragma mark CFReadStream Callback Function Prototypes

void ReadStreamCallBack(CFReadStreamRef stream, CFStreamEventType eventType, void* dataIn);

#pragma mark -

#pragma mark Audio Callback Function Prototypes

void MyAudioQueueOutputCallback(void* inClientData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer);

void MyAudioQueueIsRunningCallback(void *inUserData, AudioQueueRef inAQ, AudioQueuePropertyID inID);

void MyPropertyListenerProc(void *inClientData, AudioFileStreamID inAudioFileStream, AudioFileStreamPropertyID inPropertyID, UInt32 *ioFlags);

void MyPacketsProc(void *inClientData, UInt32 inNumberBytes, UInt32 inNumberPackets, const void *inInputData, AudioStreamPacketDescription *inPacketDescriptions);

OSStatus MyEnqueueBuffer(xxxxx* myData);

#ifdef TARGET_OS_IPHONE

void MyAudioSessionInterruptionListener(void *inClientData, UInt32 inInterruptionState);

#endif

#pragma mark -

#pragma mark Audio Callback Function Implementations

// MyPropertyListenerProc

// Receives notification when the AudioFileStream has audio packets to be

// played. In response, this function creates the AudioQueue, getting it

// ready to begin playback (playback won't begin until audio packets are

// sent to the queue in MyEnqueueBuffer).

// This function is adapted from Apple's example in AudioFileStreamExample with

// kAudioQueueProperty_IsRunning listening added.

void MyPropertyListenerProc(void *inClientData, AudioFileStreamID inAudioFileStream, AudioFileStreamPropertyID inPropertyID, UInt32 *ioFlags)

{

// this is called by audio file stream when it finds property values

xxxxx* myData = (xxxxx*)inClientData;

OSStatus err = noErr;

switch (inPropertyID) {

case kAudioFileStreamProperty_ReadyToProducePackets :

{

myData->discontinuous = true;

// the file stream parser is now ready to produce audio packets.

// get the stream format.

AudioStreamBasicDescription asbd;

UInt32 asbdSize = sizeof(asbd);

err = AudioFileStreamGetProperty(inAudioFileStream, kAudioFileStreamProperty_DataFormat, &asbdSize, &asbd);

if (err) { NSLog(@"get kAudioFileStreamProperty_DataFormat"); myData->failed = true; break; }

// create the audio queue

err = AudioQueueNewOutput(&asbd, MyAudioQueueOutputCallback, myData, NULL, NULL, 0, &myData->queue);

if (err) { NSLog(@"AudioQueueNewOutput"); myData->failed = true; break; }

// listen to the "isRunning" property

err = AudioQueueAddPropertyListener(myData->queue, kAudioQueueProperty_IsRunning, MyAudioQueueIsRunningCallback, myData);

if (err) { NSLog(@"AudioQueueAddPropertyListener"); myData->failed = true; break; }

// allocate audio queue buffers

for (unsigned int i = 0; i < kNumAQBufs; ++i) {

err = AudioQueueAllocateBuffer(myData->queue, kAQBufSize, &myData->buffers);

if (err) { NSLog(@"AudioQueueAllocateBuffer"); myData->failed = true; break; }

}

// get the cookie size

UInt32 cookieSize;

Boolean writable;

err = AudioFileStreamGetPropertyInfo(inAudioFileStream, kAudioFileStreamProperty_MagicCookieData, &cookieSize, &writable);

if (err) { NSLog(@"info kAudioFileStreamProperty_MagicCookieData"); break; }

// get the cookie data

void* cookieData = calloc(1, cookieSize);

err = AudioFileStreamGetProperty(inAudioFileStream, kAudioFileStreamProperty_MagicCookieData, &cookieSize, cookieData);

if (err) { NSLog(@"get kAudioFileStreamProperty_MagicCookieData"); free(cookieData); break; }

// set the cookie on the queue.

err = AudioQueueSetProperty(myData->queue, kAudioQueueProperty_MagicCookie, cookieData, cookieSize);

free(cookieData);

if (err) { NSLog(@"set kAudioQueueProperty_MagicCookie"); break; }

break;

}

// MyPacketsProc

// When the AudioStream has packets to be played, this function gets an

// idle audio buffer and copies the audio packets into it. The calls to

// MyEnqueueBuffer won't return until there are buffers available (or the

// playback has been stopped).

// This function is adapted from Apple's example in AudioFileStreamExample with

// CBR functionality added.

void MyPacketsProc(void *inClientData, UInt32 inNumberBytes, UInt32 inNumberPackets, const void *inInputData, AudioStreamPacketDescription *inPacketDescriptions)

{

// this is called by audio file stream when it finds packets of audio

xxxxx* myData = (xxxxx*)inClientData;

// we have successfully read the first packests from the audio stream, so

// clear the "discontinuous" flag

myData->discontinuous = false;

// the following code assumes we're streaming VBR data. for CBR data, the second branch is used.

if (inPacketDescriptions)

{

for (int i = 0; i < inNumberPackets; ++i) {

SInt64 packetOffset = inPacketDescriptions.mStartOffset;

SInt64 packetSize = inPacketDescriptions.mDataByteSize;

// If the audio was terminated before this point, then

// exit.

if (myData->trackEnded)

{

return;

}

// if the space remaining in the buffer is not enough for this packet, then enqueue the buffer.

size_t bufSpaceRemaining = kAQBufSize - myData->bytesFilled;

if (bufSpaceRemaining < packetSize) {

MyEnqueueBuffer(myData);

}

pthread_mutex_lock(&myData->mutex2);

// If the audio was terminated while waiting for a buffer, then

// exit.

if (myData->trackEnded)

{

pthread_mutex_unlock(&myData->mutex2);

return;

}

// copy data to the audio queue buffer

AudioQueueBufferRef fillBuf = myData->buffers[myData->fillBufferIndex];

memcpy((char*)fillBuf->mAudioData + myData->bytesFilled, (const char*)inInputData + packetOffset, packetSize);

pthread_mutex_unlock(&myData->mutex2);

// fill out packet description

myData->packetDescsQueue[myData->packetsFilled] = inPacketDescriptions;

myData->packetDescsQueue[myData->packetsFilled].mStartOffset = myData->bytesFilled;

// keep track of bytes filled and packets filled

myData->bytesFilled += packetSize;

myData->packetsFilled += 1;

// if that was the last free packet description, then enqueue the buffer.

size_t packetsDescsRemaining = kAQMaxPacketDescs - myData->packetsFilled;

if (packetsDescsRemaining == 0) {

MyEnqueueBuffer(myData);

}

else

{

size_t offset = 0;

while (inNumberBytes)

{

// if the space remaining in the buffer is not enough for this packet, then enqueue the buffer.

size_t bufSpaceRemaining = kAQBufSize - myData->bytesFilled;

if (bufSpaceRemaining < inNumberBytes) {

MyEnqueueBuffer(myData);

}

pthread_mutex_lock(&myData->mutex2);

// If the audio was terminated while waiting for a buffer, then

// exit.

if (myData->trackEnded)

{

pthread_mutex_unlock(&myData->mutex2);

return;

}

// copy data to the audio queue buffer

AudioQueueBufferRef fillBuf = myData->buffers[myData->fillBufferIndex];

bufSpaceRemaining = kAQBufSize - myData->bytesFilled;

size_t copySize;

if (bufSpaceRemaining < inNumberBytes)

{

copySize = bufSpaceRemaining;

}

else

{

copySize = inNumberBytes;

}

memcpy((char*)fillBuf->mAudioData + myData->bytesFilled, (const char*)(inInputData + offset), copySize);

pthread_mutex_unlock(&myData->mutex2);

// keep track of bytes filled and packets filled

myData->bytesFilled += copySize;

myData->packetsFilled = 0;

inNumberBytes -= copySize;

offset += copySize;

}

// MyEnqueueBuffer

// Called from MyPacketsProc and connectionDidFinishLoading to pass filled audio

// bufffers (filled by MyPacketsProc) to the AudioQueue for playback. This

// function does not return until a buffer is idle for further filling or

// the AudioQueue is stopped.

// This function is adapted from Apple's example in AudioFileStreamExample with

// CBR functionality added.

OSStatus MyEnqueueBuffer(xxxxx* myData)

{

OSStatus err = noErr;

myData->inuse[myData->fillBufferIndex] = true; // set in use flag

// enqueue buffer

AudioQueueBufferRef fillBuf = myData->buffers[myData->fillBufferIndex];

fillBuf->mAudioDataByteSize = myData->bytesFilled;

if (myData->packetsFilled)

{

err = AudioQueueEnqueueBuffer(myData->queue, fillBuf, myData->packetsFilled, myData->packetDescsQueue);

}

else

{

err = AudioQueueEnqueueBuffer(myData->queue, fillBuf, 0, NULL);

}

if (err) { NSLog(@"AudioQueueEnqueueBuffer"); myData->failed = true; return err; }

if (!myData->started) { // start the queue if it has not been started already

err = AudioQueueStart(myData->queue, NULL);

if (err) { NSLog(@"AudioQueueStart"); myData->failed = true; return err; }

myData->started = true;

}

// go to next buffer

if (++myData->fillBufferIndex >= kNumAQBufs) myData->fillBufferIndex = 0;

myData->bytesFilled = 0; // reset bytes filled

myData->packetsFilled = 0; // reset packets filled

// wait until next buffer is not in use

pthread_mutex_lock(&myData->mutex);

while (myData->inuse[myData->fillBufferIndex] && !myData->trackEnded)

{

pthread_cond_wait(&myData->cond, &myData->mutex);

}

pthread_mutex_unlock(&myData->mutex);

return err;

}

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流媒体播放－在线音乐（1）

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