It depends on the age of the encode. Early encodes were not very good.
However the same can be said for x264. If you look at the progress from a 2007 encode (macroblocking like hell) compared to even a 2012 release, it is really astounding. Things are always improving and it’s always good to stay on top of support for new formats.
The AMLogic S905x SoC features the AMLogic Video Enhancement Engine. This is responsible for HDR processing and it’s why you can get HDR output as well as dithering.
You have microcode updates and kernel updates which can bring a great deal of improvements. There don’t seem to be any defects in S905x sillicon; but there were some for older S905 chips which found their way in to other devices.
Dithering from HDR to SDR is effectively done by using a LUT.
In the next update, three commits will be included which are relevant:
This will allow you to select between 4 LUTs using:
echo X > /sys/module/am_vecm/parameters/video_lut_swtich
Value X can be 1 to 4.
It’s probably going to take a bit of time to improve this. We won’t get it “right” because it is not an exact science, but by offering a few options we should be able to satisfy most users in time. This is the approach that other vendors are taking.
Sam