¿Se pueden usar AVCaptureVideoDataOutput y AVCaptureMovieFileOutput al mismo tiempo?

Question

Quiero grabar video y tomar marcos al mismo tiempo con mi código.

Estoy usando AVCaptureVideoDataOutput para cuadros de agarre y AVCaptureMovieFileOutput para grabación de video. Pero no puede funcionar y obtener el código de error -12780 mientras trabaja al mismo tiempo pero de forma individual.

He buscado este problema pero no recibo respuesta. ¿Alguien tiene la misma experiencia o explicaciones? Realmente me molesta por un tiempo.

gracias.

Answer 1

No puedo responder a la pregunta formulada específica, pero he estado de grabación de vídeo con éxito y el acaparamiento de marcos al mismo tiempo usando:

• AVCaptureSession y AVCaptureVideoDataOutput a los marcos de rutas en mi propio código
• AVAssetWriter, AVAssetWriterInput y AVAssetWriterInputPixelBufferAdaptor para escribir tramas a un archivo de video H.264 codificado

Eso es sin investigar audio. Termino obteniendo CMSampleBuffers de la sesión de captura y luego presionándolas en el adaptador de memoria intermedia de píxeles.

EDIT: por lo que mi código es más o menos así, con los bits que está teniendo problemas con rozaron y haciendo caso omiso de los problemas de alcance:

/* to ensure I'm given incoming CMSampleBuffers */ 
AVCaptureSession *captureSession = alloc and init, set your preferred preset/etc; 
AVCaptureDevice *captureDevice = default for video, probably; 

AVCaptureDeviceInput *deviceInput = input with device as above, 
            and attach it to the session; 

AVCaptureVideoDataOutput *output = output for 32BGRA pixel format, with me as the 
            delegate and a suitable dispatch queue affixed. 

/* to prepare for output; I'll output 640x480 in H.264, via an asset writer */ 
NSDictionary *outputSettings = 
    [NSDictionary dictionaryWithObjectsAndKeys: 

      [NSNumber numberWithInt:640], AVVideoWidthKey, 
      [NSNumber numberWithInt:480], AVVideoHeightKey, 
      AVVideoCodecH264, AVVideoCodecKey, 

      nil]; 

AVAssetWriterInput *assetWriterInput = [AVAssetWriterInput 
            assetWriterInputWithMediaType:AVMediaTypeVideo 
                outputSettings:outputSettings]; 

/* I'm going to push pixel buffers to it, so will need a 
    AVAssetWriterPixelBufferAdaptor, to expect the same 32BGRA input as I've 
    asked the AVCaptureVideDataOutput to supply */ 
AVAssetWriterInputPixelBufferAdaptor *pixelBufferAdaptor = 
      [[AVAssetWriterInputPixelBufferAdaptor alloc] 
       initWithAssetWriterInput:assetWriterInput 
       sourcePixelBufferAttributes: 
        [NSDictionary dictionaryWithObjectsAndKeys: 
          [NSNumber numberWithInt:kCVPixelFormatType_32BGRA], 
          kCVPixelBufferPixelFormatTypeKey, 
        nil]]; 

/* that's going to go somewhere, I imagine you've got the URL for that sorted, 
    so create a suitable asset writer; we'll put our H.264 within the normal 
    MPEG4 container */ 
AVAssetWriter *assetWriter = [[AVAssetWriter alloc] 
           initWithURL:URLFromSomwhere 
           fileType:AVFileTypeMPEG4 
           error:you need to check error conditions, 
             this example is too lazy]; 
[assetWriter addInput:assetWriterInput]; 

/* we need to warn the input to expect real time data incoming, so that it tries 
    to avoid being unavailable at inopportune moments */ 
assetWriterInput.expectsMediaDataInRealTime = YES; 

... eventually ... 

[assetWriter startWriting]; 
[assetWriter startSessionAtSourceTime:kCMTimeZero]; 
[captureSession startRunning]; 

... elsewhere ... 

- (void)  captureOutput:(AVCaptureOutput *)captureOutput 
    didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer 
      fromConnection:(AVCaptureConnection *)connection 
{ 
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 

    // a very dense way to keep track of the time at which this frame 
    // occurs relative to the output stream, but it's just an example! 
    static int64_t frameNumber = 0; 
    if(assetWriterInput.readyForMoreMediaData) 
     [pixelBufferAdaptor appendPixelBuffer:imageBuffer 
         withPresentationTime:CMTimeMake(frameNumber, 25)]; 
    frameNumber++; 
} 

... and, to stop, ensuring the output file is finished properly ... 

[captureSession stopRunning]; 
[assetWriter finishWriting]; 

Answer 2

Ésta es una versión rápida de la respuesta de Tommy .

// Set up the Capture Session 
// Add the Inputs 
// Add the Outputs 


var outputSettings = [ 
    AVVideoWidthKey : Int(640), 
    AVVideoHeightKey : Int(480), 
    AVVideoCodecKey : .h264 
] 

    var assetWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo,outputSettings: outputSettings) 

    var pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput, sourcePixelBufferAttributes: 
     [ kCVPixelBufferPixelFormatTypeKey : Int(kCVPixelFormatType_32BGRA)]) 


    var assetWriter = AVAssetWriter(url: URLFromSomwhere, fileType: AVFileTypeMPEG4 , error : Error) 
     assetWriter.addInput(assetWriterInput) 
     assetWriterInput.expectsMediaDataInRealTime = true 
     assetWriter.startWriting() 
     assetWriter.startSession(atSourceTime: kCMTimeZero) 

    captureSession.startRunning() 


    func captureOutput(_ captureOutput: AVCaptureOutput, didOutputSampleBuffer sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) { 

    var imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) 
    // a very dense way to keep track of the time at which this frame 
    // occurs relative to the output stream, but it's just an example! 
    var frameNumber: Int64 = 0 

      if assetWriterInput.readyForMoreMediaData { 
    pixelBufferAdaptor.appendPixelBuffer(imageBuffer, withPresentationTime: CMTimeMake(frameNumber, 25)) 
       } 
       frameNumber += 1 } 

     captureSession.stopRunning() 
     assetWriter.finishWriting() 

No garantizo una precisión del 100%, porque soy nuevo en Swift.