录制音频

想要在ios设备上录制音频，可以使用AVAudioRecorder类，确保你已经将CoreAudio.framework 库添加到目标文件中

AV框架中的AVAudioRecorder类使得在iOS中录制音频变得很简单。开始录制音频需要提供一些参数给AVAudioRecorder实例的initWithURL:settings:error:方法： 

保存录音文件的URL 

文件的URL是一个本地URL.AV框架会根据URL的扩展名来决定录制文件的音频格式。所以要仔细选择扩展名。 

在采样之前和过程中使用的settings 

包括采样率、频道以及其他音频录制器开始录音的信息。Setting是一个dictionary对象。 

初始化错误发生时保存到error 变量中。 

你可以在出现异常的情况下得到这个实例中的值。 

initWithURL:settings:error: 方法的setting参数很有意思。很多值都可以保存在这个setting字典里，但是在本节中我们只讨论一些最重要的： 

AVFormatIDKey 

录音的格式。可能的值有： 

• kAudioFormatLinearPCM 

• kAudioFormatAppleLossless 

AVSampleRateKey 

录制音频的采样率。 

AVNumberOfChannelsKey 

录制音频的频道编号。 

AVEncoderAudioQualityKey 

录制音频的质量，可能的值有： 

AVAudioQualityMin 

• AVAudioQualityLow 

• AVAudioQualityMedium 

• AVAudioQualityHigh 

• AVAudioQualityMax 

掌握了所有这些信息后，我们可以开始写一个可以录制音频文件然后用AVAudioPlayer播放的程序。我们要做的具体事情是： 

1. 用 Apple Lossless 格式录制音频。 

2. 把录制的音频文件用Recording.m4a文件名保存到程序的Documents目录中。 

3. 在录音开始10秒后停止录制并且立刻开始播放录制的音频。 

代码：

头文件：

 #import <UIKit/UIKit.h>
 #import <CoreAudio/CoreAudioTypes.h>
 #import <AVFoundation/AVFoundation.h>

 @interface ViewController : UIViewController<AVAudioPlayerDelegate,AVAudioRecorderDelegate>
 @property(nonatomic, strong)AVAudioRecorder *audioRecorder;
 @property(nonatomic, strong)AVAudioPlayer *audioPlayer;
 -(NSString *)audioRecordingPath;
 -(NSString *)audioRecordingSettings;
 @end

实现文件：

 //
 //  ViewController.m
 //  录制音频
 //
 //  Created by Rio.King on 13-11-2.
 //  Copyright (c) 2013年 Rio.King. All rights reserved.
 //

 #import "ViewController.h"

 @interface ViewController ()

 @end

 @implementation ViewController

 - (void)viewDidLoad
 {
     [super viewDidLoad];

     NSError *error = nil;
     NSString *pathAsString = [self audioRecordingPath];
     NSURL *audioRecordingURL = [NSURL fileURLWithPath:pathAsString];
     self.audioRecorder = [[AVAudioRecorder alloc] initWithURL:audioRecordingURL settings:[self audioRecordingSettings] error:&error];
     if (self.audioRecorder != nil) {
         self.audioRecorder.delegate = self;
         /*prepare the recorder and then start the recording*/
         if ([self.audioRecorder prepareToRecord] && [self.audioRecorder record]) {
             NSLog(@"Successfully started to record.");
             /*after five seconds, let's stop the recording process*/
             [self performSelector:@selector(stopRecordingOnAudioRecorder:) withObject:self.audioRecorder afterDelay:10.0f];
         }else{
             NSLog(@"Failed to record.");
             self.audioRecorder = nil;
         }
     }else{
         NSLog(@"failed to create an instance of the audio recorder.");
     }
 }

 -(NSString *)audioRecordingPath{
     NSString *result = nil;
     NSArray *folders = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
     NSString *documentsFolder = [folders objectAtIndex:0];
     result = [documentsFolder stringByAppendingPathComponent:@"Recording.m4a"];
     return result;
 }

 - (NSDictionary *) audioRecordingSettings{
     NSDictionary *result = nil;
     /* Let's prepare the audio recorder options in the dictionary.
      Later we will use this dictionary to instantiate an audio
      recorder of type AVAudioRecorder */
     NSMutableDictionary *settings = [[NSMutableDictionary alloc] init];
     [settings
      setValue:[NSNumber numberWithInteger:kAudioFormatAppleLossless]
      forKey:AVFormatIDKey];
     [settings
      setValue:[NSNumber numberWithFloat:44100.0f]
      forKey:AVSampleRateKey];
     [settings
      setValue:[NSNumber numberWithInteger:1]
      forKey:AVNumberOfChannelsKey];
     [settings
      setValue:[NSNumber numberWithInteger:AVAudioQualityLow]
      forKey:AVEncoderAudioQualityKey];
     result = [NSDictionary dictionaryWithDictionary:settings];
     return result;
 }


 - (void) stopRecordingOnAudioRecorder:(AVAudioRecorder *)paramRecorder{
     /* Just stop the audio recorder here */
     [paramRecorder stop];
 }


 - (void)audioRecorderDidFinishRecording:(AVAudioRecorder *)recorder
                            successfully:(BOOL)flag{
     if (flag){
         NSLog(@"Successfully stopped the audio recording process.");
         /* Let's try to retrieve the data for the recorded file */
         NSError *playbackError = nil;
         NSError *readingError = nil;
         NSData *fileData =
         [NSData dataWithContentsOfFile:[self audioRecordingPath]
                                options:NSDataReadingMapped
                                  error:&readingError];
         /* Form an audio player and make it play the recorded data */
         self.audioPlayer = [[AVAudioPlayer alloc] initWithData:fileData
                                                          error:&playbackError];
         /* Could we instantiate the audio player? */
         if (self.audioPlayer != nil){
             self.audioPlayer.delegate = self;
             /* Prepare to play and start playing */
             if ([self.audioPlayer prepareToPlay] &&
                 [self.audioPlayer play]){
                 NSLog(@"Started playing the recorded audio.");
             } else {
                 NSLog(@"Could not play the audio.");
             }
         } else {
             NSLog(@"Failed to create an audio player.");
         }
     } else {
         NSLog(@"Stopping the audio recording failed.");
     }
     /* Here we don't need the audio recorder anymore */
     self.audioRecorder = nil;
 }

 - (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player
                        successfully:(BOOL)flag{
     if (flag){
         NSLog(@"Audio player stopped correctly.");
     } else {
         NSLog(@"Audio player did not stop correctly.");
     }
     if ([player isEqual:self.audioPlayer]){
         self.audioPlayer = nil;
     } else {
         /* This is not the player */
     }
 }


 - (void)audioPlayerBeginInterruption:(AVAudioPlayer *)player{
     /* The audio session has been deactivated here */
 }
 - (void)audioPlayerEndInterruption:(AVAudioPlayer *)player
                          withFlags:(NSUInteger)flags{
     if (flags == AVAudioSessionInterruptionFlags_ShouldResume){
         [player play];
     }
 }



 #pragma mark -处理音频录制过程中的中断
 - (void)audioRecorderBeginInterruption:(AVAudioRecorder *)recorder{
     NSLog(@"Recording process is interrupted");
 }
 - (void)audioRecorderEndInterruption:(AVAudioRecorder *)recorder
                            withFlags:(NSUInteger)flags{
     if (flags == AVAudioSessionInterruptionFlags_ShouldResume){
         NSLog(@"Resuming the recording...");
         [recorder record];
     }
 }




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

 @end

运行结果：

2013-11-02 21:01:52.144 录制音频[1786:a0b] Successfully started to record.

2013-11-02 21:02:02.146 录制音频[1786:a0b] Successfully stopped the audio recording process.

2013-11-02 21:02:02.160 录制音频[1786:a0b] Started playing the recorded audio.

2013-11-02 21:02:12.128 录制音频[1786:a0b] Audio player stopped correctly.

原文链接：http://blog.csdn.net/chaoyuan899/article/details/14075697