Normal
The deinterlace (blend) shader is on the context menu under Shaders. You have to be in VMR renderless mode and your graphics hardware must support at least PS 2.0In your case, the VMR Mixer was unable to perform hardware accelerated deinterlacing (gives you better quality for interlaced video). By choosing YUV Mixing mode, deinterlacing is now being performed by your graphics driver. It will provide better performance on lower end graphics hardware but image quality will suffer if you're using BOB deinterlacing. Bob is your uncle.
The deinterlace (blend) shader is on the context menu under Shaders. You have to be in VMR renderless mode and your graphics hardware must support at least PS 2.0
In your case, the VMR Mixer was unable to perform hardware accelerated deinterlacing (gives you better quality for interlaced video). By choosing YUV Mixing mode, deinterlacing is now being performed by your graphics driver. It will provide better performance on lower end graphics hardware but image quality will suffer if you're using BOB deinterlacing. Bob is your uncle.