In the above code, you don't

In the above code, you don't want to set the rotation. That will be set properly for you when you specify the output orientation of the video coming from the camera.

You don't show how you're going to be recording the video, so I'll assume that you will add the movie writer as an output of your filter. In that case, you could add the movie writer and set the rotation on that to counter the portrait orientation.

Sunset Lake Software - Comments for "How does GPUImageFilter setInputRotation: atIndex: method work?"

In the above code, you don't