Handheld, Steam Deck: Moonlight-QT Decoding Latency very high

Hello! I installed CachyOS Handheld Edition on my Steam Deck 2 days ago and I immediately noticed that, in contrast to Nobara, the “Decoding Latency” statistic is very high (>= 200ms), causing a severely degraded performance.

Input does not seem to be affected; when connecting to the same host, at the same time, my laptop shows that the mouse cursor movement from my Steam Deck appears immediately.

It really does appear to only be a hardware decoding issue.

Using software decoding works, but is not ideal.

Is mesa on 24.2.3?

its currently on 24.2.2-4. I’ll try updating.
edit: curiously, the GUI package manager didnt pick up updates. i had to run pacman -Syuu to get updates. I’ll test again after updating and a reboot.

Still happens after update. It starts at 88ms, drops to 17ms for a bit, then increases to 173ms and beyond even during active gameplay. By the time I finished typing this message, it climbed to 177 and is steadily rising.

Then it dropped to 95ms. Then to 81. Then 71. Then 64.
You get the idea. This is way higher and more instable than I get in the exact same setup, but using software acceleration gives me a decoding latency of 11-12 ms, either idle or during gameplay.

I had to make another comment to post a second screenshot. Here’s with software decoding:

Using hardware decoding with h.264 gives an initial latency of 24 (twice as much as software) and the same increasing latency symptom. Let me know if you need more information.

Did you maybe ask in Moonlight or Sunshine?

Im sadly not deeply into these topics :confused:

I have not yet, I will ask around to check if there’s a known reason why this would cause this. That’s the first install I’ve seen this problem on, so I assumed it was a CachyOS-specific issue.

Actually, CachyOS doesnt make there anything special (likely).

Maybe there is some community, where you could ask in. It could be too due newer mesa maybe.

I was able to do some more testing today and it seems to only happen when running moonlight inside the Steam Big Picture session. Running it from the desktop gives me a decoding time of 0.51ms.

That’s kind of strange.

I’ve performed a full re-imaging of my Steam Deck with SteamOS, and the issue doesn’t appear in Game Mode anymore.

I hope it doesn’t come to that, but I CAN install stock Arch Linux for testing if it’s of any help.