我有一个播放一些背景音乐的应用程序,当按下某个按钮时,它会使用导航控制器推送一个新视图。这个新视图有一个 MPMoviePlayerController 和一个带有共享 AudioSession 的 AVCaptureSession。关闭该视图后,与之前相比,背景中的声音确实很柔和。是什么原因导致播放后音量如此低?
NSError* error4 = nil;
AVAudioSession* audioSession = [AVAudioSession sharedInstance];
if (![audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&error4]) {
NSLog(@"AVAudioSession setCategory failed: %@", [error4 localizedDescription]);
}
// Set audio session property "allow mixing" to true so audio can be recorded while it is playing
UInt32 allowMixing = true;
OSStatus status = AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers, sizeof(allowMixing), &allowMixing);
if (status != kAudioSessionNoError) {
NSLog(@"AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers) failed: %ld", status);
}
// Activate the audio session
error4 = nil;
if (![audioSession setActive:YES error:&error4]) {
NSLog(@"AVAudioSession setActive:YES failed: %@", [error4 localizedDescription]);
}
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectoryPath = [paths objectAtIndex:0];
NSString *proud = [[documentsDirectoryPath stringByAppendingPathComponent:@"imissyou"] stringByAppendingPathComponent:selectedCountry];
NSURL *movieURL = [[NSURL fileURLWithPath:proud] retain];
player =
[[MPMoviePlayerController alloc] initWithContentURL: movieURL];
player.useApplicationAudioSession=YES;
[player prepareToPlay];
player.controlStyle = MPMovieControlStyleNone;
player.allowsAirPlay = NO;
player.scalingMode = MPMovieScalingModeFill;
player.view.frame = self.view.frame;
[self.view insertSubview:player.view belowSubview:vImagePreview];
[player setFullscreen:YES animated:YES];
// ...
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(movieFinishedCallback:)
name:MPMoviePlayerPlaybackDidFinishNotification
object:player];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(exitedFullscreen:) name:MPMoviePlayerDidExitFullscreenNotification object:player];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(moviePlayerWillExitFullscreen:)
name:MPMoviePlayerWillExitFullscreenNotification
object:player];
[player play];
session = [[AVCaptureSession alloc] init];
[session beginConfiguration];
session.sessionPreset = AVCaptureSessionPresetMedium;
CALayer *viewLayer = self.vImagePreview.layer;
NSLog(@"viewLayer = %@", viewLayer);
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
captureVideoPreviewLayer.frame = self.vImagePreview.bounds;
[captureVideoPreviewLayer setCornerRadius:14];
[captureVideoPreviewLayer setBorderWidth:3.0];
[captureVideoPreviewLayer setBorderColor:[[UIColor whiteColor] CGColor]];
[[vImagePreview layer] setCornerRadius:14];
[[vImagePreview layer] setBorderWidth:3.0];
[[vImagePreview layer] setBorderColor:[[UIColor whiteColor] CGColor]];
[self.vImagePreview.layer addSublayer:captureVideoPreviewLayer];
[captureVideoPreviewLayer release];
AVCaptureDevice *device = [self frontFacingCameraIfAvailable];
NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
// Handle the error appropriately.
NSLog(@"ERROR: trying to open camera: %@", error);
}
AVCaptureDevice *audioCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
NSError *error2 = nil;
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioCaptureDevice error:&error2];
AVCaptureMovieFileOutput *movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
NSString *archives = [documentsDirectoryPath stringByAppendingPathComponent:@"archives"];
NSString *editedfilename = [[selectedCountry lastPathComponent] stringByDeletingPathExtension];
NSString *datestring = [[editedfilename stringByAppendingString:@" "] stringByAppendingString:currentTime];
NSLog(@"%@", datestring);
NSString *outputpathofmovie = [[archives stringByAppendingPathComponent:datestring] stringByAppendingString:@".mp4"];
NSURL *outputURL = [[NSURL alloc] initFileURLWithPath:outputpathofmovie];
[session addInput:input];
[session addInput:audioInput];
[session addOutput:movieFileOutput];
[session commitConfiguration];
[session startRunning];
[movieFileOutput startRecordingToOutputFileURL:outputURL recordingDelegate:self];
[movieURL release];
[outputURL release];