Better way to keep two videos in sync?

[irongeek]

Hi all,
Condition is I'm using a LGP to capture camera, and Elgato GCHD for Slides/Presenter's laptop. v0.57.05. The LGP is faster than the Elgato, so I use "Use Buffering (milliseconds)" on the LGP to make it more or less match (this may help others trying to do the same). This works well, but if I unplug the VGA from my scaler, then plug it back in, the times seem to drift. Is there a better way to keep two delayed video sources in sync?

Another issues I noticed. If I set a delay in both LGP and Elgato, only one is applied. My thought was that if the Elgato was 1500ms behind the LGP, I could delayed the LGP by 3500 and the Elgato by 2000 so they would have slack time and maybe magically stay in sync. IT did not seem to work, only the delay on the LGP seemed to apply.

Other ideas? I was not sure if there was some sort of timing code being sent that could be used to keep things from drifting. I'd rather drop frames then have them out of sync.

Thanks for OBS, by the way, it will be part of my talk at Skydogcon in two weeks. :)

 

[Krazy]

OBS is currently undergoing a major rewrite, and stuff like code for devices is especially getting some new attention. It's likely stuff like this will be easier in the new version, or at least provide more options for configuration.

 

[irongeek]

Thanks. I think one of the problems I' having is the LGP is not sending video at a constant rate. With no "Use Buffer" set ahead


Then I did a bunch of motion, and you see the LGP lags behind.


Then, given time it catches up and then some


I'd rather it drop frames then be out of sync, but this may be more of an Avertmedia problem to solve.

 

[dodgepong]

Unfortunately, this is basically life for HD USB 2.0 capture devices. They have to do a lot of processing on the device itself just to be able to send HD video over USB 2.0 which is what causes delays like this. This is why I recommend PCIe and USB 3.0 capture devices over USB 2.0 capture devices to people.

 

[irongeek]

I could deal with the delay, if it was constant. It seems to be constant with the Elgato, but not the LGP. Maybe by Derbycon 4 I can spring from 5 Thunderbolt or USB 3.0 laptops and devices.