Emby failing to use Hardware Transcoding

[agottschling 2]

2 minutes ago, softworkz said:

You could turn the user into a real user and log in with those credentials and run Emby normally (for testing).

That could even be the problem: when a service user has never logged in to a regular user session, then there are a lot of registry entries missing (these get created on first login).
When the user doesn't have a full user profile, it's very well possible that this affects hw acceleration and RDP session behavior.

Gotcha. I ended up rebuilding the server from scratch on Fedora Server 32. VAAPI works perfectly on that HW. (I haven't tried using QS directly, but from what I understand, there's no advantage over VAAPI).

Thanks for the support though.

Cheers!

[Luke 42078]

Thanks for the feedback.

[softworkz 5066]

Sorry for the late reply. For QuickSync, let me put it this way: It has way more options and capabilities that the API provides, but with regards to the specific use with Emby: there are some minor advantages and some minor disadvantages, but worth bothering only in specific cases.

[agottschling 2]

1 minute ago, softworkz said:

Sorry for the late reply. For QuickSync, let me put it this way: It has way more options and capabilities that the API provides, but with regards to the specific use with Emby: there are some minor advantages and some minor disadvantages, but worth bothering only in specific cases.

Gotcha, I've left all the settings at auto for the moment. So Emby is auto selecting VAAPI. Regardless, it's working flawlessly now. Thanks for the breakdown as well, good info to have.

Cheers!

[Luke 42078]

6 minutes ago, agottschling said:

Gotcha, I've left all the settings at auto for the moment. So Emby is auto selecting VAAPI. Regardless, it's working flawlessly now. Thanks for the breakdown as well, good info to have.

Cheers!

Thanks for the feedback !

[pwhodges 2012]

2 hours ago, softworkz said:

That could even be the problem: when a service user has never logged in to a regular user session, then there are a lot of registry entries missing (these get created on first login).
When the user doesn't have a full user profile, it's very well possible that this affects hw acceleration and RDP session behavior.

I am running Emby as a service under Local System User, and am not aware of any such problems.  But are you saying that logging in first under any user will create the the necessary registry entries?  So they're not in the Current User part of the registry?

Paul

[softworkz 5066]

1 hour ago, pwhodges said:

I am running Emby as a service under Local System User, and am not aware of any such problems.  But are you saying that logging in first under any user will create the the necessary registry entries?  So they're not in the Current User part of the registry?

Paul

A user profile under Windows is actually a set of files and folders contained in the user's folder (but not all of it). One file there is "ntuser.dat" which represents a user's hive of the registry which a user will be able to access vie HKEY_CURRENT_USER once he is logged on.

When you create a new user, not much will happen unless the user logs on for the first time. Then, Windows will create a folder for the user and copy a default set of files (from e.g. c:\Users\Default) to that folder, copy the default NTUSER.DAT and load that hive as HKEY_CURRENT_USER.

What happens next, depends on the login context, i.e. whether the user logs into an interactive ("user"/"desktop") session or not. The "not" side is not only about service users. There are tons of cases (e.g. impersonation) where a non-interactive login takes place. In those cases, just minimal initialization will be performed (leaving out all UI-related initializations).
With regards to the registry, there are many things that are copied over from the system registry to the user's new hive (mostly defaults). And those defaults are divided into two sets (not an official term, just for illustration). The "full set" is only copied in case of an interactive logon.

It's not just about copying registry values, though, there are very many tasks that the OS performs during the first interactive logon (you might have seen that small window saying something like "preparing desktop" or "creating shortcuts" etc.). For a non-interactive-first login, only a minimal smaller subset of those things are done.

This behavior exists for more than 20 years and had been introduced with Windows NT.

Edited October 28, 2020 by softworkz

[pwhodges 2012]

I know all that; but do you actually expect anything to be missing in the Local System user that you know Emby needs?  As I say, I've seen no issues with running that way for a couple of years now, including hardware transcoding.

Paul

[softworkz 5066]

24 minutes ago, pwhodges said:

I know all that; but do you actually expect anything to be missing in the Local System user that you know Emby needs?  As I say, I've seen no issues with running that way for a couple of years now, including hardware transcoding.

No

5 hours ago, softworkz said:

When the user doesn't have a full user profile, it's very well possible that this affects hw acceleration and RDP session behavior.

1: The QuickSync drivers have recently changed to a registry-based configuration

2: MS have recently (maybe 2y ago) introduced some weird behavior to the RDP session host (the story about that policy etc.) - so it _might_ be possible that Windows is checking the user's security context AND other UI session related configurations of the user before deciding whether to expose the actual hardware or just the virtual graphics driver.

Not more than a theory, though, but that's where I would look at (in case of the OP)

In your case, when everything is working, then there's nothing to worry about.

 

[pwhodges 2012]

Thanks for the detailed thoughts.

Paul