Duplicate Frames in Recordings FOREVER!

JonEditor

New Member
Hello. We've been plagued with duplicate frames / juddery movement in our 29.97 OBS recordings for months.
If we step through our footage, you can see duplicate frames everywhere. The problem is intermittent and there seems to be no pattern to it.
We are using a super powerful and very expensive PC laptop. CPU usage is very low.

Can someone please glance at our record settings and see if anything is glaringly wrong (I've attached a .pdf with our settings)?
I will also attach a log file from our last session. Thanks!
 

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FerretBomb

Active Member
I do have to ask why you're recording at NTSC standard framerates instead of just running full digital until the analog-compliance pulldown is necessary?

1) Streaming over wifi. NEVER do this.
2) Recording to mp4 directly. NEVER do this. Record to FLV, or MKV if you need multi-track audio, then remux.
3) Streaming to Twitch with a keyint of 1 is going to cause problems. Why are you doing this?
4) Full RGB is disabled for streaming, and hardcoded to only send out Partial. It will cause problems unless you are ONLY recording. Swap back to Partial.
5) Your recording rate is 29.97fps, but your Elgato HD60 S input is at 30. You'll get some duplication and timing judder there on the pulldown.
6) Recording at CBR, instead of CQP or CRF. CBR is only used for streaming because the infrastructure requires it. You're wasting bitrate on low-motion scenes, and potentially choking on high motion. Swap to CQP 16 or so, adjust down for better quality, up for smaller file sizes.
 

JonEditor

New Member
I do have to ask why you're recording at NTSC standard framerates instead of just running full digital until the analog-compliance pulldown is necessary?

1) Streaming over wifi. NEVER do this.
2) Recording to mp4 directly. NEVER do this. Record to FLV, or MKV if you need multi-track audio, then remux.
3) Streaming to Twitch with a keyint of 1 is going to cause problems. Why are you doing this?
4) Full RGB is disabled for streaming, and hardcoded to only send out Partial. It will cause problems unless you are ONLY recording. Swap back to Partial.
5) Your recording rate is 29.97fps, but your Elgato HD60 S input is at 30. You'll get some duplication and timing judder there on the pulldown.
6) Recording at CBR, instead of CQP or CRF. CBR is only used for streaming because the infrastructure requires it. You're wasting bitrate on low-motion scenes, and potentially choking on high motion. Swap to CQP 16 or so, adjust down for better quality, up for smaller file sizes.

Thanks for your reply! We're recording at 29.97p because that is the output of the camera we're using. I believe the El Gato erroneously calls 29.97p "30p"

re: "keyint" what would be a normal setting for this?
 

FerretBomb

Active Member
Thanks for your reply! We're recording at 29.97p because that is the output of the camera we're using. I believe the El Gato erroneously calls 29.97p "30p"

re: "keyint" what would be a normal setting for this?
The Elgato device IS capturing and outputting to OBS at 30fps, not 29.97 according to your log. This would also be a source of duplicate frames... you're going from NTSC-analog 29.97fps coming from the camera, to the Elgato capturing and outputting at a digital 30fps, to OBS pulling it back down to 29.97 without compensating for the sync. Essentially doubling the problem and making it WAY more likely to get duped frames.

I'd recommend testing by duplicating your current Profile, and just setting everything to full digital 30 and disregarding the analog timing. You'll likely still get some duplicate frames, but likely far less than at present. It'll also likely look better on-stream too, as the Twitch stream video player isn't really set up with analog fractional-rate in mind.

For streaming to Twitch, keyint needs to be set to 2, per their streaming spec.
 
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