iOS 开发之使用 Speex 格式实现简单的语音聊天功能（二）

iOS 开发之使用 Speex 格式实现简单的语音聊天功能（二）

今天我们继续上一篇博客“IOS开发之使用Speex格式实现简单的语音聊天功能（一）”继续往下讲，主要是讲述一下PlayManager与RecorderManager两个类的功能。

首先要讲的是RecorderManager，该类的主要功能就是负责对用户的语音进行录制，和停止录制。

#import <Foundation/Foundation.h>
#import "Encapsulator.h"@protocol RecordingDelegate <NSObject>- (void)recordingFinishedWithFileName:(NSString *)filePath time:(NSTimeInterval)interval;
- (void)recordingTimeout;
- (void)recordingStopped;  //录音机停止采集声音
- (void)recordingFailed:(NSString *)failureInfoString;@optional
- (void)levelMeterChanged:(float)levelMeter;@end@interface RecorderManager : NSObject <EncapsulatingDelegate> {Encapsulator *encapsulator;NSString *filename;NSDate *dateStartRecording;NSDate *dateStopRecording;NSTimer *timerLevelMeter;NSTimer *timerTimeout;
}@property (nonatomic, weak)  id<RecordingDelegate> delegate;
@property (nonatomic, strong) Encapsulator *encapsulator;
@property (nonatomic, strong) NSDate *dateStartRecording, *dateStopRecording;
@property (nonatomic, strong) NSTimer *timerLevelMeter;
@property (nonatomic, strong) NSTimer *timerTimeout;+ (RecorderManager *)sharedManager;- (void)startRecording;- (void)stopRecording;- (void)cancelRecording;- (NSTimeInterval)recordedTimeInterval;@end

该类的主要结构就是上面头文件中所展示的，包括一个委托RecordingDelegate，以及RecorderManager本身的类函数。该类使用了单例模式，通过调用函数shareManager即可获取它实例本身。

startRecording函数负责录音工作：

- (void)startRecording {if ( ! mAQRecorder) {mAQRecorder = new AQRecorder();OSStatus error = AudioSessionInitialize(NULL, NULL, interruptionListener, (__bridge void *)self);if (error) printf("ERROR INITIALIZING AUDIO SESSION! %dn", (int)error);else{UInt32 category = kAudioSessionCategory_PlayAndRecord;error = AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(category), &category);if (error) printf("couldn't set audio category!");//添加属性监听，一旦有属性改变则调用其中的propListener函数error = AudioSessionAddPropertyListener(kAudioSessionProperty_AudioRouteChange, propListener, (__bridge void *)self);if (error) printf("ERROR ADDING AUDIO SESSION PROP LISTENER! %dn", (int)error);UInt32 inputAvailable = 0;UInt32 size = sizeof(inputAvailable);// we do not want to allow recording if input is not availableerror = AudioSessionGetProperty(kAudioSessionProperty_AudioInputAvailable, &size, &inputAvailable);if (error) printf("ERROR GETTING INPUT AVAILABILITY! %dn", (int)error);// we also need to listen to see if input availability changeserror = AudioSessionAddPropertyListener(kAudioSessionProperty_AudioInputAvailable, propListener, (__bridge void *)self);if (error) printf("ERROR ADDING AUDIO SESSION PROP LISTENER! %dn", (int)error);error = AudioSessionSetActive(true); if (error) printf("AudioSessionSetActive (true) failed");}}//获取音频存放地址filename = [NSString stringWithString:[Encapsulator defaultFileName]];NSLog(@"filename:%@",filename);if ( ! apsulator) {apsulator = [[Encapsulator alloc] initWithFileName:filename];apsulator.delegete = self;}else {[apsulator resetWithFileName:filename];}if ( ! mAQRecorder->IsRunning()) {NSLog(@"audio session category : %@", [[AVAudioSession sharedInstance] category]);Boolean recordingWillBegin = mAQRecorder->StartRecord(encapsulator);if ( ! recordingWillBegin) {if ([self.delegate respondsToSelector:@selector(recordingFailed:)]) {[self.delegate recordingFailed:@"程序错误，无法继续录音，请重启程序试试"];}return;}}self.dateStartRecording = [NSDate date];if (!levelMeterStates){levelMeterStates = (AudioQueueLevelMeterState *)malloc(sizeof(AudioQueueLevelMeterState) * 1);}self.timerLevelMeter = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(updateLevelMeter:) userInfo:nil repeats:YES];self.timerTimeout = [NSTimer scheduledTimerWithTimeInterval:60 target:self selector:@selector(timeoutCheck:) userInfo:nil repeats:NO];
}

在startRecording函数中，先实例化类AQRecorder，该类是用C++实现的，主要用作录制音频文件（核心类）。随后调用函数AudioSessionInitialize初始化音频，并添加回调函数interruptionListener，若监听被打断则停止AQRecorder类的录制工作。若返回值不是error则对音频添加相应的属性，并且回调函数为propListener，若监听的属性不正确，就停止录音。当然了，所有的音频都是以文件为单位的，在startRecording函数中利用[EncapsulatordefaultFileName]来获取音频的存放地址，Encapsulator类也是一个很重要的类，它封装了ogg,极大的方便了我们调用它里面的函数来实现录音。

函数- (void)stopRecording的作用大家想必都知道就是停止录音，但是不取消音频；

函数- (void)cancelRecording的作用则是停止录音并且取消；

函数recordedTimeInterval则是获取录音时间，单位为float;

接下来，我们来说一下PlayerManager这个类，该类主要负责解析音频文件并播放音频。类结构如下：

#import <Foundation/Foundation.h>
#import <AVFoundation/AVFoundation.h>
#import "Decapsulator.h"@protocol PlayingDelegate <NSObject>- (void)playingStoped;@end@interface PlayerManager : NSObject <DecapsulatingDelegate, AVAudioPlayerDelegate> {Decapsulator *decapsulator;AVAudioPlayer *avAudioPlayer;}
@property (nonatomic, strong) Decapsulator *decapsulator;
@property (nonatomic, strong) AVAudioPlayer *avAudioPlayer;
@property (nonatomic, weak)  id<PlayingDelegate> delegate;+ (PlayerManager *)sharedManager;- (void)playAudioWithFileName:(NSString *)filename delegate:(id<PlayingDelegate>)newDelegate;
- (void)stopPlaying;@end

可以看到该类与RecordingManager一样，也使用了单例并且其中有委托对象PlayingDelegate，函数playingStoped用于暂停播放。

该类有两个主要函数"playAudioWithFileName"与“stopPlaying”前者可以根据音频的文件名字来播放音频，后者则是停止播放。

- (void)playAudioWithFileName:(NSString *)filename delegate:(id<PlayingDelegate>)newDelegate {if ( ! filename) {return;}if ([filename rangeOfString:@".spx"].location != NSNotFound) {[[AVAudioSession sharedInstance] setActive:YES error:nil];[self stopPlaying];self.delegate = newDelegate;self.decapsulator = [[Decapsulator alloc] initWithFileName:filename];self.decapsulator.delegate = self;[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];[self.decapsulator play];//开启距离监听[self startProximityMonitering];}else if ([filename rangeOfString:@".mp3"].location != NSNotFound) {if ( ! [[NSFileManager defaultManager] fileExistsAtPath:filename]) {NSLog(@"要播放的文件不存在:%@", filename);[self.delegate playingStoped];[newDelegate playingStoped];return;}[self.delegate playingStoped];self.delegate = newDelegate;NSError *error;self.avAudioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL URLWithString:filename] error:&error];if (self.avAudioPlayer) {[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];[[AVAudioSession sharedInstance] setActive:YES error:nil];self.avAudioPlayer.delegate = self;[self.avAudioPlayer play];[self startProximityMonitering];}else {[self.delegate playingStoped];}}else {[self.delegate playingStoped];}
}

该函数首先判断音频文件是.spx格式的还是.mp3格式，随后通过解析类Decapsulator来解析音频并播放之（与Encapsulator类对应）。再类中还实现了距离监听的功能，当用户脸靠近手机时则会按掉屏幕打开听他，当远离时则打开扬声器屏幕变亮。

总而言之，对好奇想尝试一下开发ios语音的人来说，这几个类绝对是个福音，封装的很好，调用起来也很方便。若想用作开发语音聊天的产品，则需要我们要加深理解他背后压缩与解压缩的的原理了。