OBS Starts it's nVidia Encoder on Slow and Double Pass by Default?

[Acey05]

Sorry if in the wrong place, or if it's not a bug, but I figured I would put this here? Also, it's mostly related to Recording, but I figured some feedback might be important here.

In the latest versions of OBS, when the nVidia Codecs (especially HEVC) are selected, the default settings (iirc) are with the following options enabled:

Preset: Slower (P6)
Multipass: Two Pass Quarter
Psycho Visual Tuning: On

While these settings are great in quality, they're terrible in general for several reasons:

IIRC, the old Quality Preset is now mapped to P4 Medium, however P4 Medium is with extra bell and whistles, P2 is the last known Preset that doesn't put stress on the GPU outside of the NVENC Encoding requirments (such as Splits or such), just like the Quality Preset on the old OBS Presets (P1 is pretty much free from any needs).

Multipass, even if Quarter, still has extra overhead. Usually you want a Single Pass to bypass any latency or extra GPU stress, no? Is Two Quarter better than a Single Pass now?

Psycho Visual Tuning I guess is not that stressful in theory, but it used to be off, is it ON now because it's free or did something change?

The reason I'm pointing out these things, is because most 6th generation NVENC GPU's (especially bugdets ones, like 1060) cannot run these settings enabled together with UNCAPPED or DOUBLE-SYNCED games. Even if you're playing a small free indie like this: https://sirtartarus.itch.io/how-to-build-a-snowman

Literally, a PS1 looking Unity, but because it's doesn't have proper Synced Renderer, it will introduce massive stutters (because it's pretty much flooding the GPU at that point), and outside of capping it externally with specific tools, it makes even recording such games almost impossible.

The reason I'm pointing this all out, is because this directly affects OBS. If you decide to Record with a Slower NVENC Preset, and your GPU is getting hammered, even if you're streaming with h264 CPU, both the Stream and the Videos will get the same stutters, neither one ends up being safe from the other.

I never had this issue with the older H264 NVENC Quality settings in the older OBS, and I was confused why the newer OBS default settings where stuttering (not dropping frames mind you) and why sometimes the audio was desyncing.

 

[AaronD]

I don't have an answer, but I've also seen on my rig and a bunch of other complaints in this forum, that a lot of GPU's can't do Two Pass Quarter Resolution. They'll do Two Pass Full Resolution just fine, but trying to use the default gives an error popup that quotes verbatim from the log, but chops off the part that actually tells you what's wrong!!

This is true on both Windows and Linux. Possibly on Mac as well, depending on what range of hardware is allowed to run that OS.

 

[Acey05]

They'll do Two Pass Full Resolution just fine

I can confirm this, it will work, but sadly for a budget graphic card, and even according to nVidia Documents, anything with a double pass will have a cost, just like BFrames (although BFrames footprint is so tiny, it might as well be free and no latency issues).

chops off the part that actually tells you what's wrong

True, I basically had to test out the settings, because the OBS Logs actually don't show any issues with these codecs.

 

[Harold]

The simple output mode presets are getting different settings in the v29 release cycle.

 

[Acey05]

The simple output mode presets are getting different settings in the v29 release cycle.

Cheers, and thanks.

Hopefully HEVC as well, since I narrowed it down as the worst on the bunch and almost impossible to run a recording reliably on it (at least on a budget GPU, it still stutteres on the lowest settings with a capped game, even below 30).

A 20% file reduction is nice on the higher settings, but if dumping all the settings to low brings it back up to the same H264 size again, with the same quality, it kinda defeats the purpose of using HEVC, especially if H264 can be pushed to even slightly better quality on the same NVENC encoder.

 

[Acey05]

UPDATE: I wanted to apologize to Harold and anyone else from OBS Team, it seems like even the older versions of OBS are suffering from video stuttering, even on the OLD default settings.

After some more testings, even doing a full OBS cleanup, it still happens every 45 to 60 minutes or so, sometimes less then 5 minute intervals, I couldn't understand why (unlike HEVC which happened every few minutes or intense GPU use).

I even ran checks, OBS wasn't pegging the GPU at all and the videos were stuttering. I even tried FFMPEG with lowest settings on the OBS 27, it still happened, both CPU and GPU.

I even recorded some giant pixels, the videos wouldn't not stop stuttering.

I was able to narrow down the problem, it was NDI...again.

I don't know why honestly, I think NDI just is beyond broken at this point on OBS. I mean it works properly if you rescale your Video to 720p and use below 60FPS? My old videos were 720p/50fps, so I'm going to guess that's the limit for NDI?

OBS 28 suffers the worst of this due to the 4.10 revision I think, I tried all the NDI Runtime and Toolsets and none of them worked. OBS 27 with the old setup still works I think, although I would need to reinstall everything to recheck.

So yeah, wanted to put this info out there that very likely, NDI is the reason videos have interval stutters, and not OBS itself.