如何用iPad录音？

Question

我需要一个在 iPad 上录制语音的好示例或指南。无论我说什么，我都希望能够稍后回放。我该怎么做？

Answer 1

事实上，根本没有例子。这是我的工作代码。用户按下导航栏上的按钮即可触发录制。录音使用 CD 质量（44100 个样本）、立体声（2 通道）线性 PCM。请注意：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（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，但您可以轻松弄清楚。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 将录制的音频保存为当前编辑的对象中的 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

}

来自这个答案 - 如何使用 AVAudioRecorder 在 iPhone 上录制音频？