xcode：如何使用 AVFoundation 录制音频后保存音频文件

Question

我浏览了与该主题相关的各种帖子，但答案并没有真正帮助。我使用这个教程来实现音频文件的录制和播放。似乎缺少的是如何永久保存记录。当我退出应用程序时，声音文件就在那里，但里面什么也没有。我什至不知道它是在保存 rocerd 还是只是创建文件。 这是一个代码示例：

NSArray *dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docsDir = [dirPaths objectAtIndex:0];
NSString *soundFilePath = [docsDir
                               stringByAppendingPathComponent:@"tmpSound.caf"];

tempRecFile = [NSURL fileURLWithPath:soundFilePath];

NSDictionary *recSettings = [NSDictionary 
                                    dictionaryWithObjectsAndKeys:
                                    [NSNumber numberWithInt:AVAudioQualityMin],
                                    AVEncoderAudioQualityKey,
                                    [NSNumber numberWithInt:16], 
                                    AVEncoderBitRateKey,
                                    [NSNumber numberWithInt: 2], 
                                    AVNumberOfChannelsKey,
                                    [NSNumber numberWithFloat:44100.0], 
                                    AVSampleRateKey,
                                    nil];

recorder = [[AVAudioRecorder alloc] initWithURL:tempRecFile settings:recSettings error:nil];
[recorder setDelegate:self];
[recorder prepareToRecord];
[recorder record];

我在此处看到了此问题的可能解决方案，但由于我是 iOS 新手，所以我没有真的明白了，否则它对我不起作用。

请帮助并提供代码示例。我阅读了有关 AVFoundation 和其他类的文档，但没有得到积极的结果。

SOS :)

更新 这是我的录制方法：

-(IBAction)recording{
    //***** METHOD for recording

    if(isNotRecording){
        isNotRecording = NO;
        [recButton setTitle:@"Stop"  forState:UIControlStateNormal];
        recStateLabel.text = @"Recording";

        [recorder setDelegate:self];
        [recorder prepareToRecord];
        [recorder record];

    }
    else{
        isNotRecording = YES;
        [recButton setTitle:@"Rec Begin" forState:UIControlStateNormal];
        playButton.hidden = NO;
        recStateLabel.text = @"Not recording";
        [recorder stop];
    }


}

这是我的 viewDidLoad：

- (void)viewDidLoad
{
    //record sound test code - start
    isNotRecording = YES;
    //playButton.hidden = YES;
    recStateLabel.text = @"Not recording";

    AVAudioSession *audioSession = [AVAudioSession sharedInstance];

    [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

    [audioSession setActive:YES error:nil];
    //record sound test code -  END

    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    // code for generating the sound file that is to be saved
    NSArray *dirPaths;
    NSString *docsDir;

    dirPaths = NSSearchPathForDirectoriesInDomains(
                                                   NSDocumentDirectory, NSUserDomainMask, YES);
    docsDir = [dirPaths objectAtIndex:0];
    NSString *soundFilePath = [docsDir
                               stringByAppendingPathComponent:@"sound.caf"];

    NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];

    NSDictionary *recordSettings = [NSDictionary 
                                    dictionaryWithObjectsAndKeys:
                                    [NSNumber numberWithInt:AVAudioQualityMin],
                                    AVEncoderAudioQualityKey,
                                    [NSNumber numberWithInt:16], 
                                    AVEncoderBitRateKey,
                                    [NSNumber numberWithInt: 2], 
                                    AVNumberOfChannelsKey,
                                    [NSNumber numberWithFloat:44100.0], 
                                    AVSampleRateKey,
                                    nil];

    NSError *error = nil;

    recorder = [[AVAudioRecorder alloc]
                     initWithURL:soundFileURL
                     settings:recordSettings
                     error:&error];

    if (error)
    {
        NSLog(@"error: %@", [error localizedDescription]);

    } else {
        [recorder prepareToRecord];
    }

}

这是我的播放方法：

-(IBAction)playback{
    //AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:temporaryRecFile error:nil];
    NSError *error;
    // setting the uri of the formed created file
    NSArray *dirPaths;
    NSString *docsDir;



dirPaths = NSSearchPathForDirectoriesInDomains(
                                               NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
NSString *soundFilePath = [docsDir
                           stringByAppendingPathComponent:@"sound.caf"];

NSURL *soundFileURL = [NSURL fileURLWithPath:soundFilePath];

AVAudioPlayer *player = [[AVAudioPlayer alloc]initWithContentsOfURL:soundFileURL error:&error];



[player setNumberOfLoops:0];
[player prepareToPlay];
[player setVolume:1];
[player play];
NSLog(@"URL je: %@", soundFileURL);


//method 2
if (error)
    NSLog(@"Error: %@", 
          [error localizedDescription]);
else
{

    [player play];
    if(player.isPlaying==YES)
    {
        NSLog(@"It's playing");
    }
}

}

我希望这能让我清楚地知道我在做什么。 有什么建议我可能错了吗？

Answer 1

您需要停止记录才能将数据永久保存到文件中：

[recorder stop];

Answer 2

问题是当你告诉XCode（在viewDidLoad方法中）[recorder prepareToRecord];它会删除以前录制的音频文件。删除“if”语句中的那段代码，当您退出并返回应用程序时，您的音频文件将被保存。

Answer 3

仅供参考——“[录音机prepareToRecord]”方法创建一个新的音频文件，覆盖任何以前录制的文件。