我正在开发一个用于录制视频和音频的应用程序，但似乎音频无效。有时候它有效，但大部分时间都没有。
这是我的代码
self.captureSession = [[AVCaptureSession alloc] init];
[self.captureSession setSessionPreset:AVCaptureSessionPreset352x288];
AVCaptureDevice *videoDevice = [self frontCamera];
AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
self.videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];
self.audioInput = [[AVCaptureDeviceInput alloc] initWithDevice:audioDevice error:nil];
self.stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *stillImageOutputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:
AVVideoCodecJPEG, AVVideoCodecKey, nil];
[self.stillImageOutput setOutputSettings:stillImageOutputSettings];
self.movieOutput = [[AVCaptureMovieFileOutput alloc] init];
// Setup capture session for taking pictures
[self.captureSession addInput:self.videoInput];
[self.captureSession addInput:self.audioInput];
[self.captureSession addOutput:self.stillImageOutput];
[self.captureSession addOutput:self.movieOutput];