10-bit rendering in Emby Theater?

[ExpedientFalcon 6]

Hi, I have a large number of videos that are encoded in 10-bit, either with HEVC or AV1. I noticed when inspecting them in Emby Theater with the Stats for Nerds tool that they're being forcefully downsampled to yuv420p8--there's some "autoconvert" step that appears in the mpv logs that is causing this to happen (although I'm not sure what is triggering that). I've verified that Emby Theater is using my specified mpv.conf. However, when I use mpv as an external player, it correctly renders in yuv420p10le. I have an HDR monitor with HDR enabled in Windows settings. I'm using direct play--no transcoding.

A couple of thoughts, possible causes?:

- Emby Theater is on a much older ffmpeg version than the mpv on my system--related?

- Is there just some limitation where Emby Theater just can't render in 10-bit (due to being an Electron app or some weirdness)?

- Or is there just something misconfigured on my system?

Edited March 2, 2022 by ExpedientFalcon

[Luke 42078]

Hi, what ffmpeg version are you referring to, the one in the windows app?

[ExpedientFalcon 6]

Yes, sorry if I wasn't clear about that. This is with the Emby Theatre 3.0.15 for Windows.

[Guest]

You'll need to update mpv. Especially now, as mpv can now play Dolby Vision media, via tone mapping and using gpu-next. But that would also require Emby updating the settings to allow use of gpu-next. A lot has changed since Emby last built mpv.

[Luke 42078]

Here's the latest test build, updated today with mpv 34.1:

https://www.dropbox.com/s/77rxtiuexrsnlf9/emby-theater.zip?dl=0

We'll finally update the published build soon. Thanks.

[ExpedientFalcon 6]

I gave the updated build some testing, and the build itself didn't resolve my issue. (Though I still much appreciate the update!)

So I dug a little deeper and found the difference was that mpv on my computer was using the hardware D3D renderer, while Emby was using the software OpenGL renderer. Switching the "Video output" setting in Emby Theatre to "gpu" caused Emby to also switch to the D3D renderer, producing identical 10-bit output to my mpv binary. So, problem solved by that setting.

[Luke 42078]

Thanks for the feedback.