Issue direct playing 4k HDR content

[TheDreadPirate]

Transcoding VIDEO still causes tone mapping. So you are still losing HDR when transcoding the video. But the first two logs you shared are only transcoding the audio. So that HDR limitation doesn't apply.

The first two logs you shared are both only transcoding the audio and appear to transcoding without issue. The third is CPU transcoding. And slower than real time (~15fps). So it looks like you did not enable hardware accelerated transcoding for that playback.

The CPU you have is a Skylake family CPU and the version of Quick Sync it has does not support decoding HEVC 10-bit. Meaning that even if you properly setup Quick Sync you would not be able to tone map HDR to SDR since that requires the video to be decoded on the iGPU.

As for the playback issues in the first two logs, are you running out of space on your C drive? Since transcodes are written to disk.