How to capture raw frame from Nvidia card?

I want to change color format of Nvidia card by NVAPI, for example from RGB to YUV422. But I am not sure if the change is successful. So I used DVI2USB DUO to grab video frame from the Nvidia card. But FrmGrab_Frame asks for color format as input parameter, my question is if DVI2USB can get the color format of raw video stream from Nvidia card?

Thanks in advance.

Unfortunately there is no way to query the colour space directly from our devices so I do not believe it is possible to capture as raw stream