Question / Help NVenc doesn't record smoothly

A

Astralogic

Member
Hi, using nvenc I don't get smooth recordings. I'm using a 1080 and the GPU is only utilized about 50%, it technically should be recording fine, but my 60fps is not smooth through the videos. It's fine because I can record using the CPU, but I'd like to know if anyone has experienced nvenc not being perfect.
 
Really need an uploaded logfile that includes a few minutes of a recording attempt in it to assist with troubleshooting performance issues.
 
Your GPU is struggling a bit at 2560x1440@60fps, not entirely sure as to why as I thought a 1080 should also be fine for 4k60fps recording as well. In saying that, I don't have a 1080 or an nVidia card so am not familiar with the performance of the nVidia encoder.

Some things to try for troubleshooting (Will need to test one at a time to see if they help, not all at once):
If you don't, cap your fps to 60 as it will decrease the load on your GPU.
Using High Quality, Low latency OR High Performance, Low Latency Preset
Keyframe Interval: 2
Using VBR instead of CQP - Bitrate of at least 50k

Note: To cap your fps I recommend using 3rd party software such as MSI AfterBurner or EVGA Precision, with a capped fps of 61-63, as if you get any screen tearing it will move the horizontal 'tear' to another location on the screen due to the slightly different refresh rate timing. Using V Sync can and most likely will induce input lag, which I can't stand, however if you don't notice it then it is fine to use though it can sometimes hurt performance as it forces your GPU to effectively idle momentarily to wait for your monitor to refresh the frame (Which is why it induces input lag)

Note: flv container format is better to use than mp4 as it allows for the footage to be played back/usable in the event of a crash of OBS Studio, your game, Windows OS, etc. One caveat of flv container format is it only allows for one audio track, not multiple.
 
I already do cap my framerate, how can you tell that my gpu is struggling?

I'll just use x264 instead, it seems to work perfectly.
 
Astralogic said:
I already do cap my framerate, how can you tell that my gpu is struggling?

I'll just use x264 instead, it seems to work perfectly.
Click to expand...
Very sorry, it was 3am for me when I replied... Usually give more info...

12:46:54.632: Output 'simple_file_output': Total encoded frames: 4719
12:46:54.632: Output 'simple_file_output': Total drawn frames: 4720
12:46:54.632: Output 'simple_file_output': Number of lagged frames due to rendering lag/stalls: 8 (0.2%)

If it was to state a similar line saying skipped frames due to encoding lag, that would be your CPU load affecting your recording/stream attempts. Rendering is your GPU being overloaded.

In regards to encoding/rendering overload causing frame lag, it is fine to have some, just means you are really pushing your system... Better to have none though, if you do have some you want it to be as few as possible with a 0.0% ratio to drawn frames, for example below from my logfile:

21:00:36.186: Output 'adv_file_output': Total encoded frames: 107903
21:00:36.186: Output 'adv_file_output': Total drawn frames: 107910
21:00:36.186: Output 'adv_file_output': Number of skipped frames due to encoding lag: 5 (0.0%)

Using x264 encoder at your resolution with your CPU & GPU setup would probably be the best method as you should be able to push quite a high bitrate, ~50-60k with near lossless quality settings. x264 encoder runs off the CPU itself so it is inherently resource hungry yet the quality it yields is far superior to hardware encoders like NVENC/AMD AMF/QSync.
 
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