Question

我正在使用WKWebView在我的应用中显示全屏YouTube视频，并使用AVCaptureSession在YouTube上浏览和播放视频时在后台录制音频和视频。按下按钮时捕获会话开始。但是，在录制过程中，当选择YouTube视频并开始全屏播放时，它会立即意外结束录制，因为会调用处理录制结束的委托方法。

有人可以向我解释如何解决这个问题吗？不太确定这是否完全相关，但我收到了_BSMachError: (os/kern) invalid capability (20) _BSMachError: (os/kern) invalid name (15) and Unable to simultaneously satisfy constraints.等错误消息，尽管后者似乎引用了一个单独的AutoLayout问题。任何帮助将不胜感激。

另外，我尝试使用UIWebView代替WKWebView。当我使用UIWebView时，问题是视频录制时YouTube视频甚至无法播放。它将在黑屏上打开并保持在0:00。

这是按下最初开始录制的按钮。

- (void) buttonClickedStart:(UIButton*)sender //button to start/end recording {
    if (!WeAreRecording) {
        [self setupVideoCapture]; 
        //----- START RECORDING -----
        WeAreRecording = YES;
        [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryRecord error:nil];

        //Create temporary URL to record the video to for later viewing
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *basePath = [paths objectAtIndex:0];
        NSString *outputPath = [[NSString alloc] initWithFormat:@"%@", [basePath stringByAppendingPathComponent:@"output.mp4"]];
        if ([[NSFileManager defaultManager] isDeletableFileAtPath:outputPath])
            [[NSFileManager defaultManager] removeItemAtPath:outputPath error:NULL];
        NSURL *outputURL = [[NSURL alloc] initFileURLWithPath:outputPath];
        [MovieFileOutput startRecordingToOutputFileURL:outputURL recordingDelegate:self];
        self.outputURLs = outputURL;
    }
    else {
        //----- STOP RECORDING -----
        WeAreRecording = NO;
        [MovieFileOutput stopRecording];
    }
}

这是按下按钮时调用的方法。它设置并启动表示为CaptureSession的捕获会话。

- (void)setupVideoCapture { 
    // Sets up recording capture session
    CaptureSession = [[AVCaptureSession alloc] init];

    // Add video input to capture session
    AVCaptureDevice *VideoDevice = [AVCaptureDevice     defaultDeviceWithMediaType:AVMediaTypeVideo];
    if (VideoDevice) {
        NSError *error;
        VideoInputDevice = [[AVCaptureDeviceInput alloc] initWithDevice:[self CameraWithPosition:AVCaptureDevicePositionFront] error:&error];
        if (!error) {
            if ([CaptureSession canAddInput:VideoInputDevice])
                [CaptureSession addInput:VideoInputDevice];
         }
    }

    // Add audio input to capture session
    AVCaptureDevice *audioCaptureDevice = [AVCaptureDevice   defaultDeviceWithMediaType:AVMediaTypeAudio];
    NSError *error = nil;
    AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput  deviceInputWithDevice:audioCaptureDevice error:&error];
    if (audioInput) {
        [CaptureSession addInput:audioInput];
    }

    // Add movie file output to the capture session
    MovieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
    [MovieFileOutput setMovieFragmentInterval:kCMTimeInvalid];
    if ([CaptureSession canAddOutput:MovieFileOutput])
        [CaptureSession addOutput:MovieFileOutput];

    // Set the output properties (you don't really need to see this code)
    [self CameraSetOutputProperties]; // (We call a method as it also has to be done after changing camera)
    [CaptureSession setSessionPreset:AVCaptureSessionPresetMedium];

    //----- START THE CAPTURE SESSION RUNNING -----
    [CaptureSession startRunning];
}

这是声明和设置WKWebView的地方。

- (void)viewDidAppear:(BOOL)animated {
        [super viewDidAppear:animated];

        // Add recording button
        CGSize screenSize = [[UIScreen mainScreen] bounds].size;
        CGRect rect = CGRectMake(0, 0, screenSize.width, 337);
        UIButton *start = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        [start addTarget:self action:@selector(buttonClickedStart:) forControlEvents:UIControlEventTouchUpInside];
        [start setFrame:CGRectMake(30, 338, 35, 35)];
        [start setTitle:@"" forState:UIControlStateNormal];
        [start setExclusiveTouch:YES];
        [start setBackgroundImage:[UIImage imageNamed:@"start.png"] forState:UIControlStateNormal];
        [self.view addSubview:start];

        // Add web view
        webView = [[WKWebView alloc] initWithFrame:rect];
        [self.view addSubview:webView];
        NSString *webSite = @"http://www.youtube.com";
        NSURL *url = [NSURL URLWithString:webSite];
        NSURLRequest *request = [NSURLRequest requestWithURL:url];
        webView.navigationDelegate = self;
        webView.UIDelegate = self;
        [webView loadRequest:request]; // Load up Youtube           
        [self.view addSubview:webView];
}

Answer 1

看起来唯一缺少的是在音频会话中设置与他人混合选项和播放和录制类别。

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionMixWithOthers error:nil];

编辑：设置一个简单的测试并且它有效，希望这有帮助！

Answer 2

的原因

_BSMachError：（os / kern）无效功能（20）_BSMachError：（os / kern）无效名称（15）

可能是因为Apple引入了App Transport Security，强制使用“HTTPS”网址。虽然您可以修改info.plist以使其成为例外，但对于旧版URL，他们强烈建议您对任何新URL使用HTTPS。

如果您只是将自己的YouTube网址更新为“https：”，则可以轻松解决此问题

在网络视图中播放视频意外结束了背景视频录制？

2 个答案: