Frames skipping due to encoding lag on a dedicated machine.

Gabelven

New Member
Hey there,

As this is my 1st post on OBS forum, please forgive me if i will do anything against "the forum policy" and ping me what should i correct :)

Im encountering a strange OBS behavior on some of my newer software encoding setups, that I am running on Linux.

Here is the setup:

Hardware:
MB: ASUS PRIME X299-DELUXE II
CPU: Intel(R) Core(TM) i9-10980XE CPU @ 3.00GHz (18core)
RAM: 64GB (4x16GB DDR4/3GHz)
Video: NV Quadro RTX 4000
Capture: BMD 8K Pro


Software:
Ubuntu 20.04.3 LTS
OBS 27.1.3
BMD Drivers - 12.1


OBS Settings:

1080p@5994, 8mbps (192kbps audio), x264 (CPU encoding), 2s key, PVT

Here is the problem:

Encoding works normally until i am trying to stream anything better than "faster/main". On "fast" im encountering skipped frames (lots of them actually). CPU levels are stable.
Zrzut ekranu 2022-01-12 o 15.58.04.jpg
There are no error indicators in logs, just information about skipped frames after stopping the stream.
Zrzut ekranu 2022-01-12 o 16.02.22.png
Setup is used strictly and only for streaming, running only some minor monitoring tools in the background, that are almost non-impacting on the system. Ubuntu is updated on a regular basis. I've checked for similar issues on the other machines running same setup (3 of them actually, one without Quadro, but in this case it does not matter i presume). Same problem there as well.

I even tried to play with "threads" option. By setting them to a higer number (higher than physically available, like 100), numbers of skipped frames seems to be lesser, but not that much. It is still a problem.

Issue does not appear on GPU encoding (it handles even 4K on best setting without too much stress), but that is not the method I am interested for the streaming at this moment. CPU streaming is crucial for some of my shows.

I am trying to solve this problem for a few days now, so in "desperation" I thought that someone might have any ideas for a potential fix (or maybe a procedure that can pinpoint the genesis of the issue). After all, on this setup, I expected to achieve much more than just "faster" ;).
 

Gabelven

New Member
Smal update on the issue: Seems like reducing b-frames to "1" solves the issue, but still, its a temporary workaround, not a solution. It there anyone competent enough to help me? ;) Or was I too accurate in description that I removed all "usual solutions" out of the way, and nobody I left here to help me? :(
 
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