【原】AVAudio录制，播放 （解决真机播放音量太小）

原文链接：http://www.cnblogs.com/A--G/p/4624526.html

最近学习AVFoundation里的audio操作，最基本的录制和播放，参考了一个Code4pp的 一个 demo后，发现写的不错，但是里面有一些问题，1，由于没有添加控制输入输出流的AVAudioSession，真机播放无法录音；2.真机播放的音量很小；

　　下面是源代码：

 //
 //  ViewController.h
 //  AudioRecorder
 //
 //  Created by MZN on 15-7-1.
 //  Copyright (c) 2015年 MZN. All rights reserved.
 //

 #import <UIKit/UIKit.h>
 #import <AudioToolbox/AudioToolbox.h>
 #import <AVFoundation/AVFoundation.h>

 @interface ViewController : UIViewController<AVAudioRecorderDelegate>
 {
     AVAudioRecorder *recorder;
     NSTimer *timer;
     NSURL *urlPlay;

 }
 @property (retain, nonatomic) IBOutlet UIButton *btn;
 @property (retain, nonatomic) IBOutlet UIImageView *imageView;
 @property (retain, nonatomic) IBOutlet UIButton *playBtn;
 @property (retain, nonatomic) AVAudioPlayer *avPlay;

 @end

 //
 //  ViewController.m
 //  AudioRecorder
 //
 //  Created by MZN on 15-7-1.
 //  Copyright (c) 2014年 MZN. All rights reserved.
 //

 #import "ViewController.h"

 @interface ViewController ()

 @end

 @implementation ViewController
 @synthesize btn;
 @synthesize imageView = _imageView;
 @synthesize playBtn = _playBtn;
 @synthesize avPlay = _avPlay;

 - (void)viewDidLoad
 {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.
     [self audio];
     [self.btn addTarget:self action:@selector(btnDown:) forControlEvents:UIControlEventTouchDown];
     [self.btn addTarget:self action:@selector(btnUp:) forControlEvents:UIControlEventTouchUpInside];
     [self.btn addTarget:self action:@selector(btnDragUp:) forControlEvents:UIControlEventTouchDragExit];
     [self.playBtn addTarget:self action:@selector(playRecordSound:) forControlEvents:UIControlEventTouchDown];

 }

 - (IBAction)playRecordSound:(id)sender
 {
     if (self.avPlay.playing) {
         [self.avPlay stop];
         return;
     }
     AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:urlPlay error:nil];
     self.avPlay = player;
     [player release];
     [self.avPlay play];
 }

 - (IBAction)btnDown:(id)sender
 {

     //创建录音文件，准备录音
     if ([recorder prepareToRecord]) {
         //开始
         [recorder record];
     }

     //设置定时检测
     timer = [NSTimer scheduledTimerWithTimeInterval: target:self selector:@selector(detectionVoice) userInfo:nil repeats:YES];
 }

 - (IBAction)btnUp:(id)sender
 {
     double cTime = recorder.currentTime;
     if (cTime > ) {//如果录制时间<2 不发送
         NSLog(@"发出去");
     }else {
         //删除记录的文件
         [recorder deleteRecording];
         //删除存储的
     }
     [recorder stop];
     [timer invalidate];
 }

 - (IBAction)btnDragUp:(id)sender
 {
     //删除录制文件
     [recorder deleteRecording];
     [recorder stop];
     [timer invalidate];

     NSLog(@"取消发送");
 }

 - (void)audio
 {
     //录音设置
     NSMutableDictionary *recordSetting  = [[NSMutableDictionary alloc] init];
     //设置录音格式  AVFormatIDKey==kAudioFormatLinearPCM
     [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
     //设置录音采样率(Hz) 如：AVSampleRateKey==8000/44100/96000（影响音频的质量）
     [recordSetting setValue:[NSNumber numberWithFloat:] forKey:AVSampleRateKey];
     //录音通道数  1 或 2
     [recordSetting setValue:[NSNumber numberWithInt:] forKey:AVNumberOfChannelsKey];
     //线性采样位数  8、16、24、32
     [recordSetting setValue:[NSNumber numberWithInt:] forKey:AVLinearPCMBitDepthKey];
     //录音的质量
     [recordSetting setValue:[NSNumber numberWithInt:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];
     //是否使用浮点数采样
     [recordSetting setValue:@(YES) forKey:AVLinearPCMIsFloatKey];

     NSString *strUrl = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
     NSURL *url = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/lll.aac", strUrl]];
     urlPlay = url;

     NSError *error;
     //初始化
     recorder = [[AVAudioRecorder alloc]initWithURL:url settings:recordSetting error:&error];
     //开启音量检测
     recorder.meteringEnabled = YES;
     recorder.delegate = self;
 }

 - (void)detectionVoice
 {
     [recorder updateMeters];//刷新音量数据
     //获取音量的平均值  [recorder averagePowerForChannel:0];
     //音量的最大值  [recorder peakPowerForChannel:0];

     double lowPassResults = pow(, (0.05 * [recorder peakPowerForChannel:]));
     NSLog(@"%lf",lowPassResults);
     //最大50  0
     //图片 小-》大
     if (<lowPassResults<=0.06) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_01.png"]];
     }else if (0.06<lowPassResults<=0.13) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_02.png"]];
     }else if (0.13<lowPassResults<=0.20) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_03.png"]];
     }else if (0.20<lowPassResults<=0.27) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_04.png"]];
     }else if (0.27<lowPassResults<=0.34) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_05.png"]];
     }else if (0.34<lowPassResults<=0.41) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_06.png"]];
     }else if (0.41<lowPassResults<=0.48) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_07.png"]];
     }else if (0.48<lowPassResults<=0.55) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_08.png"]];
     }else if (0.55<lowPassResults<=0.62) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_09.png"]];
     }else if (0.62<lowPassResults<=0.69) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_10.png"]];
     }else if (0.69<lowPassResults<=0.76) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_11.png"]];
     }else if (0.76<lowPassResults<=0.83) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_12.png"]];
     }else if (0.83<lowPassResults<=0.9) {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_13.png"]];
     }else {
         [self.imageView setImage:[UIImage imageNamed:@"record_animate_14.png"]];
     }
 }

 - (void) updateImage
 {
     [self.imageView setImage:[UIImage imageNamed:@"record_animate_01.png"]];
 }

 - (void)didReceiveMemoryWarning
 {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 @end

一、问题1:添加AVAudioSession， 这里由于录制和play都需要，所以设置Category为AVAudioSessionCategoryPlayAndRecord:

        NSError *categoryError = nil;
     AVAudioSession *audioSession = [AVAudioSession sharedInstance];
     [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&categoryError];
     [audioSession setActive:YES error:&categoryError];

二、问题2:真机播放音量太小，有人说设置AudioSession属性里把sizeof设成1可行:

 //    UInt32 doChangeDefault = 1;
 //    AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryDefaultToSpeaker, sizeof(doChangeDefault), &doChangeDefault);

使用后的确可以，但是ios7.0之后，AudioSessionSetProperty已经被弃用了，于是乎

~keep looking for~~~

____________ 15分钟之后_______________

在stackoverflow上，一位朋友说audioSession的属性基本迁移到AVFoundation里了，建议我们多使用AVFoundation里的API。

     NSError *audioError = nil;
     BOOL success = [audioSession overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:&audioError];
     if(!success)
     {
         NSLog(@"error doing outputaudioportoverride - %@", [audioError localizedDescription]);
     }

初步实现了录制和播放功能，进一步的研究正在进行ing~~~~

需要修改过demo的朋友可以从这里下载：http://files.cnblogs.com/files/A--G/AudioRecorder%E6%94%B9%E8%BF%9B%E6%92%AD%E6%94%BE%E9%9F%B3%E9%87%8F.zip

参考链接： 1，http://code4app.com/ios/%E5%BD%95%E9%9F%B3%E5%92%8C%E6%92%AD%E6%94%BE/51ba821b6803fa6901000000

　　　　　2. http://stackoverflow.com/questions/18807157/how-do-i-route-audio-to-speaker-without-using-audiosessionsetproperty

本文属于原创，转载请注明，谢谢 http://www.cnblogs.com/A--G/p/4624526.html