ios - 如何使用 AVAudioRecorder 在 iPhone 上录制音频？

现在 iPhone 3.0 SDK 是公开的，我想我可以向那些已经玩过 3.0 SDK 的人提出这个问题。我想在我的应用程序中录制音频，但我想使用 AVAudioRecorder 而不是像示例 SpeakHere 所示的旧的录制方式。 iPhone Dev Center 中没有任何关于如何最好地做到这一点的示例，仅引用了这些类。我是 iPhone 开发的新手，所以我正在寻找一个简单的示例来帮助我入门。

最佳答案

实际上，根本没有任何例子。
这是我的工作代码。录制由用户按下导航栏上的按钮触发。
录音使用 cd 质量(44100 个样本)、立体声(2 channel )线性 pcm。注意:如果您想使用不同的格式，尤其是编码格式，请确保您完全了解如何设置 AVAudioRecorder 设置(请仔细阅读音频类型文档)，否则您将永远无法正确初始化它。还有一件事。在代码中，我没有展示如何处理计量数据，但您可以很容易地弄清楚。
最后，请注意在撰写本文时 AVAudioRecorder 方法 deleteRecording 会使您的应用程序崩溃。这就是我通过文件管理器删除录制文件的原因。录制完成后，我使用 KVC 在当前编辑的对象中将录制的音频保存为 NSData。

#define DOCUMENTS_FOLDER [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]


- (void) startRecording{

UIBarButtonItem *stopButton = [[UIBarButtonItem alloc] initWithTitle:@"Stop" style:UIBarButtonItemStyleBordered  target:self action:@selector(stopRecording)];
self.navigationItem.rightBarButtonItem = stopButton;
[stopButton release];

AVAudioSession *audioSession = [AVAudioSession sharedInstance];
NSError *err = nil;
[audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];
if(err){
    NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
    return;
}
[audioSession setActive:YES error:&err];
err = nil;
if(err){
    NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
    return;
}

recordSetting = [[NSMutableDictionary alloc] init];

[recordSetting setValue :[NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];

[recordSetting setValue :[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];



// Create a new dated file
NSDate *now = [NSDate dateWithTimeIntervalSinceNow:0];
NSString *caldate = [now description];
recorderFilePath = [[NSString stringWithFormat:@"%@/%@.caf", DOCUMENTS_FOLDER, caldate] retain];

NSURL *url = [NSURL fileURLWithPath:recorderFilePath];
err = nil;
recorder = [[ AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&err];
if(!recorder){
    NSLog(@"recorder: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
    UIAlertView *alert =
    [[UIAlertView alloc] initWithTitle: @"Warning"
                               message: [err localizedDescription]
                              delegate: nil
                     cancelButtonTitle:@"OK"
                     otherButtonTitles:nil];
    [alert show];
    [alert release];
    return;
}

//prepare to record
[recorder setDelegate:self];
[recorder prepareToRecord];
recorder.meteringEnabled = YES;

BOOL audioHWAvailable = audioSession.inputIsAvailable;
if (! audioHWAvailable) {
    UIAlertView *cantRecordAlert =
    [[UIAlertView alloc] initWithTitle: @"Warning"
                               message: @"Audio input hardware not available"
                              delegate: nil
                     cancelButtonTitle:@"OK"
                     otherButtonTitles:nil];
    [cantRecordAlert show];
    [cantRecordAlert release];
    return;
}

// start recording
[recorder recordForDuration:(NSTimeInterval) 10];

}

- (void) stopRecording{

[recorder stop];

NSURL *url = [NSURL fileURLWithPath: recorderFilePath];
NSError *err = nil;
NSData *audioData = [NSData dataWithContentsOfFile:[url path] options: 0 error:&err];
if(!audioData)
    NSLog(@"audio data: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
[editedObject setValue:[NSData dataWithContentsOfURL:url] forKey:editedFieldKey];

//[recorder deleteRecording];


NSFileManager *fm = [NSFileManager defaultManager];

err = nil;
[fm removeItemAtPath:[url path] error:&err];
if(err)
    NSLog(@"File Manager: %@ %d %@", [err domain], [err code], [[err userInfo] description]);



UIBarButtonItem *startButton = [[UIBarButtonItem alloc] initWithTitle:@"Record" style:UIBarButtonItemStyleBordered  target:self action:@selector(startRecording)];
self.navigationItem.rightBarButtonItem = startButton;
[startButton release];

}

- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *) aRecorder successfully:(BOOL)flag
{

NSLog (@"audioRecorderDidFinishRecording:successfully:");
// your actions here

}

关于ios - 如何使用 AVAudioRecorder 在 iPhone 上录制音频？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/1010343/