iOS 上的 AVCapture 会话中没有音频

Posted 2023-03-07

【中文标题】iOS 上的 AVCapture 会话中没有音频

【英文标题】：No Audio In AVCapture Session on iOS

【发布时间】：2017-05-30 20:38:55

【问题描述】：

我的应用程序模拟 FaceTime 通话，同时通过前置摄像头记录使用它的人，并在屏幕上显示它的预览，就像是真正的 FaceTime 通话一样。然后，它会在 FaceTime 通话中以“其他人”的身份播放预先录制的视频。它应该在按下“结束”按钮或主电影结束时从前置摄像头保存视频。在前者中，它运行良好，但如果主电影运行完成，则保存的电影输出没有音频。有什么想法吗？

#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

【参考方案1】：

找到了。

movieFileOutput.movieFragmentInterval = kCMTimeInvalid;