The specialized hardware in GPUs is targeted at encoding content on the fly. While you could use this to encode a video for later playback it has a couple of dr

The specialized hardware in GPUs is targeted at encoding content on the fly. While you could use this to encode a video for later playback it has a couple of drawbacks when it comes to size and quality, namely h264, keyframes, static frame allocations, no multipass encoding, etc. ... This is why video production software that supports GPU encoding usually marks this option as "create a preview, fast!". It's fast but that's it. If you want a good quality/size ratio you would use something like VP9 for example. Because of missing specialized hardware and internals of the codec itself currently this is very slow. Add multipass encoding, something like 4k at 60 frames, adaptive codec bitrates and suddenly encoding a second takes a over two minutes ... the result is the need for specialized hardware.