I apologize to everyone, I have not been active in the last period. Unfortunately, this will continue to be the case in the near future, but I will try to take the time to answer questions when my free time allows.
I'm using an S912 box with this build, and I found that some H265/1080p files (can't put the link because ©) can't be played with the hardware decoder.
I checked the demo you sent and it is a known issue with older versions that playback errors can occur with some 10-bit H.265 files on hardware accelerated playback. This affects not only the S912, but also the S905x series SoCs. Unfortunately, with the kernel v3.14, the microcode of the decoders is closed source, so these playback problems cannot be fixed in this version.
However, newer LE versions are based on the mainline kernel, which is no longer based on binary microcode from the BSP kernel.