Input is a 4k 30FPS MP4 video. I even tried setting the downscale height to 1080 but I still get a memory error CUDA out of memory. Tried to allocate 558 MiB (GPU 0; 8.00 GiB tocal capacity; 5.06 GiB already allocated; 390.22 MiB free; 592.32 MiB cached).

Problem is that this is a pretty high end card, my system has 96GB of RAM and I have basically nothing running. The GPU memory is less than .8 GiB before I start the program. I am using Alpha .39 because .40 does not recognize my video card. Also tried .38.

RAM is not so important

1080p needs 10 GB VRam and more

4k needs round about 40 GB VRam

If you want more answers come to  

https://discord.gg/fF7rcgS

Why not use split frames option?

So who has a video card with 40GB of dedicated GPU memory? Why not shared memory? I will look at the split frames option but just to do a basic HD video and having to have a top of the line video card is not going to be very useful for most end users.