AVCaptureMovieFileOutput - no active/enabled connections

[Jonas Bruun Nielsen]

In RubyMotion, I'm using AVFoundation for screencapture in an attempt to implement this snippet from the Mac Developer Library. The program should capture video from the screen and write to a .mov file.

I don't quite understand why I'm getting this error:

* -[AVCaptureMovieFileOutput startRecordingToOutputFileURL:recordingDelegate:] - no active/enabled connections.

The simple code is:

# Setup recording pipeline
@session = AVCaptureSession.alloc.init
@session.sessionPreset = AVCaptureSessionPresetMedium
input = AVCaptureScreenInput.alloc.initWithDisplayID(KCGDirectMainDisplay)
@session.addInput(input)
movieFileOutput = AVCaptureMovieFileOutput.alloc.init
if @session.canAddOutput(movieFileOutput)
  @session.addOutput(movieFileOutput)
else
  Logger.error "Could not add ouput #{movieFileOutput}"
end
@session.startRunning()


# Delete exisiting file
fileManager = NSFileManager.defaultManager
path = "~/Desktop/video.mov"
if fileManager.fileExistsAtPath(path)
  err = Pointer.new(:object)
  unless fileManager.defaultManager.removeItemAtPath(path, error:err)
    Logger.error "Can't delete existing movie"
  end
end


# Start recording
movieFileOutput.startRecordingToOutputFileURL(NSURL.fileURLWithPath(path), recordingDelegate:self) # <--- Problem

What am I doing incorrect?

[Jonas Bruun Nielsen]

Hey guys

I would really appreciate any input on this. I've confirmed it to work with the exact same procedure in Objective-C. 

Let me know, if I can provide any other information. 

Thanks,

Jonas

[Jonas Bruun Nielsen]

Here's a sample app explaining the problem:

https://github.com/JonasNielsen/moviefileoutput-test/

I also submitted a support ticket to the RubyMotion team. Hopefully they can help clear out the issue.

[Jonas Bruun Nielsen]

Thanks to the lovely Joffrey from the RubyMotion team, the problem is now solved. 

For someone coming across this thread in the future, the issue was using the wrong constant for main display id. Correct is CGMainDisplayID().