Android TV (Shield) - Why is this HEVC 10-bit 4K video getting transcoded

[seemebreakthis]

Would be nice to figure out why this one particular 4K demo video gets transcoded during playback on my Android TV Jellyfin app.

Video:  HEVC Main 10 (I have other videos in the same format that can do direct playback)
Audio:  AAC (don't think this is the issue)
Container:  mpegts (This is the only 4K HEVC Main 10 video I have that's in this format)

Could it be the container?  Would be happy to make this video available for download by anyone else if this would help determine why transcoding takes place.

Because my H/W (Synology) sucks at 4K to 4K transcoding, right now on the shield I have to use Kodi instead to get this video to play smoothly.

[TheDreadPirate]

Is the video HDR? If so, which kind?

[seemebreakthis]

Is the video HDR?  If so, which kind?

When I play it back on Windows (using Media Player Classic or MPC-HC), it says:

Video: HEVC 3840x2160 59.94fps [V: hevc main 10 L5.2, yuv420p10le, 3840x2160]
Audio: AAC 48000Hz stereo 127kbps [A: aac lc, 48000 Hz, stereo, 127 kb/s]

Not sure if "yuv420p10le" means HDR.

[TheDreadPirate]

Not all yuv420p10le is HDR, but all HDR is yuv420p10le. Having said that, L5.2 is typically not supported by most streaming devices. This is likely the reason for the transcode.

[seemebreakthis]

It's actually no big deal to not be able to direct play, since Kodi (running on the same device) seems to be able to decode and play the video with no problem.

But if I can direct play on Kodi, does that mean the device itself is actually capable of streaming the video without any transcoding?

[TheDreadPirate]

Software decoding performance varies greatly between devices and codecs so there is a lot of potential for a poor playback experience. Most streaming devices will opt to not try to software decode.

Kodi will software decode anyway if the hardware can't accelerate the decode process with the understanding that the experience might be inconsistent between devices.