Question / Help NVENC H.264 not working correctly

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LowerBigfoot

New Member
Hi I recently installed and set up OBS Studio. However I ran into a problem with the NVENC encoder that allows me to record multiple audio tracks at lossless visual quality. I switched to another setting on FFMPEG, which only allowed me one audio tracks (but multiple audio sources), so I could record something. I'd like to be able to use NVENC so I have more options to edit. Here is the log file of when I went back to NVENC to test it out on BF1 the other day. https://gist.github.com/anonymous/cc239739afe7a4ab3c8f433a008b35ab

What happens is I record just fine at 1440p60, no framerate drops or anything, and then when I go to check the footage, it's at about 5-10 frames per second. The multiple audio tracks do appear in Premiere however.

Keep in mind, I switched back and forth between the two about ten times, using tweaked settings, and still I could not fix it.

With FFMPEG I get about a 5 frame hit when recording, but get ok footage in the end, albeit only one audio track.

This is how I set up the NVENC: http://i.imgur.com/wjJ1Tle.png

And this is how I set up FFMPEG: http://i.imgur.com/nkOCwlt.png

These are my specs: http://i.imgur.com/I4bPn9a.png

I'd be happy to receive any help, thanks.
 
B

Beardedbob

Member
Hi,

The Nvenc CQP is a bit low which means higher load on the Nvenc core to provide higher quality. Given the rez you want to record in and fps, try it at around 25 and see if that gives you a smoother recording with higher fps, then tweak it lower from there and report back. Another option is to switch the OBS recording settings from simple to advance as this will give you more ability to tweak it.

You could also use CBR or VBR and see what outputs you get, as a note Nvenc require more Bitrate than x264 so start around 40000 and you should get a decent output, you could lower this if its not a high motion capture or higher it if you are getting Artifacts until the Nvenc core overloads

Cheers

Bob
 
R

RytoEX

Forum Admin
Forum Moderator
Developer
Code: 
20:25:28.971:    format:            RGBA
20:25:28.971: GPU conversion not available for format: 6
[...]
20:27:28.918: Output 'adv_ffmpeg_output': Number of skipped frames due to encoding lag: 6139 (94.1%)
20:27:28.918: Output 'adv_ffmpeg_output': Number of lagged frames due to rendering lag/stalls: 1209 (18.2%)
[...]
20:30:40.073: Output 'adv_file_output': Number of skipped frames due to encoding lag: 6064 (107.9%)
20:30:40.073: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 2215 (34.8%)

You're not recording just fine - you're skipping and lagging frames everywhere. You might be playing the game just fine while the encoder is running, but the encoder is choking in the background.

Why are you using RGB as your color format? Do you need to record at 1440p@60f? Are you running BF1 fullscreen?

To see if your system can handle recording 1440p@60f while playing BF1, test these settings:

Output
Output Mode: Simple
Recording
Recording Quality: Indistinguishable Quality, Large File Size
Encoder: Hardware (NVENC)

If that works without a hitch (or at least with considerably less skipped/lagged frames), then that's good. If it doesn't, then you may need to look at some kind of framerate limit (V-Sync, limit capture rate, etc.) or reducing your recording resolution.


Edit: @Beardedbob also makes a good suggestion to try setting your CQP to 25 to see if that improves things, but I'm not sure it will improve enough given how high your skip/lag rates are.
 
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