Do you know the likelihood of being able to use hardware accelerated opencl at some point? Like is this some sort of Intel driver/sdk limitation or work that needs to be prioritized in-house?
Also, have you seen poor ARC transcode quality, such as blockiness? I get much better results with my CPU, but it can’t handle transcoding HDR content. Even 1080p is bad. Here are clips from a 1080p transcode:
ARC 770:
Intel 9600K:
Some scenes are better and some are even worse. Do you have any control over this quality?

