iOS上的AVCapture会话中无音频

Question

My app simulates a FaceTime call, while simultaneously recording the people using it through the front facing camera, and showing a preview of it on the screen, as though it were a real FaceTime call. It then plays a pre-recorded video as the "other person" on the FaceTime call. It is supposed to save the video off the front camera either when the End button is pressed, or when the main movie ends. In the former, it works perfect, but if the main movie runs to completion, the saved output of the movie has no audio. Any ideas what is going on?

#import "MovieView.h"
#import <AudioToolbox/AudioToolbox.h>

@implementation MovieView
@synthesize selectedCountry, vImagePreview, playit;

- (void)viewDidLoad { 
    [super viewDidLoad];
    NSDate *today = [NSDate date];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"MMM d hh:mm:ss a"];
    // display in 12HR/24HR (i.e. 11:25PM or 23:25) format according to User Settings
    NSString *currentTime = [dateFormatter stringFromDate:today];

    self.navigationController.navigationBarHidden = YES;
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleDefault];
    [[UIApplication sharedApplication] setStatusBarHidden:NO];

    NSError* error4 = nil;
    AVAudioSession* audioSession = [AVAudioSession sharedInstance];
    [audioSession setCategory:AVAudioSessionCategoryAmbient error:&error4];
    OSStatus propertySetError = 0; 
    UInt32 allowMixing = true; 
    propertySetError |= AudioSessionSetProperty(kAudioSessionProperty_OtherMixableAudioShouldDuck, sizeof(allowMixing), &allowMixing);

    // Activate the audio session
    error4 = nil;
    if (![audioSession setActive:YES error:&error4]) {
        NSLog(@"AVAudioSession setActive:YES failed: %@", [error4 localizedDescription]);
    }






   //tests


    // Set audio session category to "play and record"
       //endtests

    //this is the end of recording the video and audio
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectoryPath = [paths objectAtIndex:0];

   NSString *proud = [[documentsDirectoryPath stringByAppendingPathComponent:@"proud"] stringByAppendingPathComponent:selectedCountry];

    NSURL  *movieURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"BlueHarvest" ofType:@"mp4"]];
    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);

    self.captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
    self.captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    self.captureVideoPreviewLayer.frame = self.vImagePreview.bounds;
    [self.captureVideoPreviewLayer setCornerRadius:14];
    [self.captureVideoPreviewLayer setBorderWidth:3.0];
    [self.captureVideoPreviewLayer setBorderColor:[[UIColor whiteColor] CGColor]];
    self.captureVideoPreviewLayer.connection.videoOrientation = AVCaptureVideoOrientationLandscapeRight;
    [[vImagePreview layer] setCornerRadius:14];


    [[vImagePreview layer] setBorderWidth:3.0];


    [[vImagePreview layer] setBorderColor:[[UIColor whiteColor] CGColor]];
    [self.vImagePreview.layer addSublayer:self.captureVideoPreviewLayer];
    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];
    AVCaptureConnection *videoConnection = nil;

    for ( AVCaptureConnection *connection in [movieFileOutput connections] )
    {
        NSLog(@"%@", connection);
        for ( AVCaptureInputPort *port in [connection inputPorts] )
        {
            NSLog(@"%@", port);
            if ( [[port mediaType] isEqual:AVMediaTypeVideo] )
            {
                videoConnection = connection;
            }
        }
    }

    if([videoConnection isVideoOrientationSupported]) // **Here it is, its always false**
    {
        [videoConnection setVideoOrientation:AVCaptureVideoOrientationLandscapeRight];
    }

    [session commitConfiguration];
    [session startRunning];

    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];




    [movieFileOutput startRecordingToOutputFileURL:outputURL recordingDelegate:self];

    NSLog(@"OutputURL%@", outputURL);

}
-(void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];

    UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
    switch (orientation) {
        case UIInterfaceOrientationPortrait:
            [self.captureVideoPreviewLayer.connection setVideoOrientation:AVCaptureVideoOrientationPortrait];
            break;
        case UIInterfaceOrientationPortraitUpsideDown:
            [self.captureVideoPreviewLayer.connection setVideoOrientation:AVCaptureVideoOrientationPortraitUpsideDown];
            break;
        case UIInterfaceOrientationLandscapeLeft:
            [self.captureVideoPreviewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeLeft];
            break;
        case UIInterfaceOrientationLandscapeRight:
            [self.captureVideoPreviewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeRight];
            break;
    }
}
- (void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error {
    //finished
    NSLog(@"ErrorMessage%@", error);
}
-(IBAction)endcall {

    [player stop];
    [session stopRunning];
}
-(AVCaptureDevice *)frontFacingCameraIfAvailable
{
    NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    AVCaptureDevice *captureDevice = nil;
    for (AVCaptureDevice *device in videoDevices)
    {
        if (device.position == AVCaptureDevicePositionFront)
        {
            captureDevice = device;

            break;
        }
    }

    //  couldn't find one on the front, so just get the default video device.
    if ( ! captureDevice)
    {
        captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    }

    return captureDevice;
}

- (void) movieFinishedCallback:(NSNotification*) aNotification {    
    NSLog(@"MovieDone");
     [player stop];
    [player.view removeFromSuperview];   
    [[NSNotificationCenter defaultCenter]
     removeObserver:self
     name:MPMoviePlayerPlaybackDidFinishNotification
     object:player];
    [session stopRunning];
    [self.navigationController popToRootViewControllerAnimated:NO];

}

- (void) exitedFullscreen:(NSNotification*) aNotification {   
    NSLog(@"MovieDone");
    [player.view removeFromSuperview];   
    [[NSNotificationCenter defaultCenter]
     removeObserver:self
     name:MPMoviePlayerDidExitFullscreenNotification
     object:player];
}
- (void)moviePlayerWillExitFullscreen:(NSNotification*) aNotification {
    [player stop];
    [session stopRunning];
    [self dismissMoviePlayerViewControllerAnimated];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerWillExitFullscreenNotification object:player];
}



@end

Answer 1

找到了。

movieFileOutput.movieFragmentInterval = kCMTimeInvalid;