Question Question regarding Capture Card CPU usage with no encoding/compression ?

[HomeNetworkingIssues]

Hello,

I was interested in purchasing a capture card to record my PC desktop.

Though I've heard that purchasing a capture card if all you're doing is recording your desktop is useless, I'm not 100% certain.

My problem is this; I'm trying to record the output from a PowerPoint presentation which uses animations (specifically morph animations).

Given that this is PowerPoint, and not some triple-A game, I'd assume my PC/Laptop would be able to handle this without issue as my PC has:

CPU = 13th Gen i9-13900HX
GPU = 4070 mobile
RAM = 32 GB DDR5 at 4800 Mhz
M.2 = WD SN740 (1 TB)

I also use a good cooling pad (LLano v12) to ensure that my laptop remains cool during my recordings.

The weird thing is, no matter what sort of encoding I use in OBS (NVENC or not), no matter what file size (compressed (H.264, H.265 and AV1) or uncompressed), no matter how cool my components are (using the LLano at 600 RPM or 2800 RPM), whenever I record, I notice choppiness in the recording as well as in the rendering from PowerPoint itself (I'm also using PowerPoint 365 with the latest updates).

This also happens when using Nvidia Shadowplay (and I made sure to update to the latest Nvidia drivers)

I've also tried multiple video players (VLC with hardware encoding/decoding via Nvidia's optimizations and without), Windows Media Player (new and legacy), MPV, and so on.

Once again, all I'm doing is recording PowerPoint (at 1920x1080p at 60 Hz - so not even 4K), and no matter what I try, there's choppiness on playback and during the rendering of the PowerPoint presentation.

However, I noticed that when I was using OBS to record my screen (I have a dual screen setup with my laptop screen being screen 1 and a separate TV monitor being screen 2), but I selected the wrong screen and I was configured to display to only one screen (rather than duplicate my displays), that the PowerPoint rendering choppiness went away completely.

In other words, I set my display setting to "Show only on 1" (which is my laptop screen) and OBS is misconfigured to record from my TV monitor (which is screen 2 - meaning that the recording itself is just that of a black screen).

I feel that there's some bug (likely in PowerPoint) or some hardware issue, but don't want to keep digging further to figure out what the problem is (as that could take a while).

I was hoping that a capture card could potentially help me out in this situation, and was looking at something like the new Elgato 4K X.

Even though I'm not recording at 4K, I've heard that the Elgato 4K X uses new hardware (vs their older capture cards), and would likely be worth the purchase (as I've spent more than 2 weeks going through all sorts of settings, scenarios, trying to find something that works and haven't found anything).

The only worry I have with the capture card (even if I don't enable enable any compression), is that it will impact performance (just like I saw with OBS when not using compression).

I also have a second laptop (weaker which only uses a i7-1265U and Iris Xe GPU), which I could use to record to, but even with that, I'm not sure if the recording itself won't have any impact on performance (on the laptop which is running the PowerPoint presentation).

I'm thinking if a capture card is necessary (with no CPU usage), I might need to use something like a BlackMagic HyperDeck, but doing so would require that I also purchase an HDMI to SDI converter (as the BlackMagic only supports SDI in), and by that point, you're spending nearly $750 (which is quite a lot).

Any help would be greatly appreciated.

 

[TerryLaze]

1. also try quicksync, QSV in OBS, powerpoint might be using the nvidia card to do calculations and using it for recording at the same time would cause issues.

2. similarly using the same disk to save the powerpoint output to as you use to record to will use more writing bandwidth than the disk has, especially since uncompressed means huge giant file size.

3. Doesn't powerpoint output cover you? I see they have animgif as output, I'm sure there are plugins that will give you better video output if you need it.
https://support.microsoft.com/en-gb...ide-show-a598753e-92de-4f1b-8393-714db4d334b4

 

[HomeNetworkingIssues]

1. also try quicksync, QSV in OBS, powerpoint might be using the nvidia card to do calculations and using it for recording at the same time would cause issues.

2. similarly using the same disk to save the powerpoint output to as you use to record to will use more writing bandwidth than the disk has, especially since uncompressed means huge giant file size.

3. Doesn't powerpoint output cover you? I see they have animgif as output, I'm sure there are plugins that will give you better video output if you need it.
https://support.microsoft.com/en-gb...ide-show-a598753e-92de-4f1b-8393-714db4d334b4

Hello TerryLaze,

So unfortunately nothing worked.

That said, I finally got things working by:

1. Disabling Optimus (in BIOS), as this was setting my internal display adapter to the iGPU rather than my 4070.
2. Using ShadowPlay rather than OBS.
3. Ensure ShadowPlay is recording at my native resolution (4K) and at 60 Hz (as ShadowPlay doesn't support anything above 60 Hz).
4. Ensure that Windows is only displaying output to my laptop screen (and not duplicating the output to my monitor).
5. Ensure Windows is outputting at native resolution of 4K (as dropping the resolution to 1080p actually resulted in worse performance and quality).
6. Ensure scaling is disabled (as Windows recommends 150% scaling at 4K).
7. Ensure refresh rate is set to 240 Hz.
8. Ensure that I'm using my cooling pad (at 600 RPM). This may not be necessary, but it definitely helped keep temps below 40 degrees Celsius.
9. Ensure that I view the recorded video through the Nvidia optimized version of VLC.

With all of those things, I was finally able to get clean, good looking and performant screen captures.

Quite frankly it's insane that I had to do that to get good screen captures from PowerPoint (of all applications), but it's fixed now.

As for exporting to a GIF or video using PowerPoint, none of that worked. The video and GIF outputs were choppy (no matter whether I output at 4K or 1080p or used MP4 or WMV). Also, didn't matter what video player I used.

What's worse, PowerPoint has a bug where it outputs video at 62 FPS (not 60 FPS), and there's no way to force it to 60 FPS (even when using a VB script in PowerPoint to force the frame rate and quality level).

Once again, absolutely insane that I needed to go through this on such a powerful laptop, but it is what it is.

Thanks again for your help, as it forced me to re-examine things.

Regards,
Nelson

 

[TerryLaze]

7. Ensure refresh rate is set to 240 Hz.

Just saying but it could be that it just looks stuttery but isn't stuttery because 240 messes with the 60FPS.
It would be interesting to playback one of the stuttery outputs on a system that has an 60Hz native display.

 

[HomeNetworkingIssues]

Just saying but it could be that it just looks stuttery but isn't stuttery because 240 messes with the 60FPS.
It would be interesting to playback one of the stuttery outputs on a system that has an 60Hz native display.

I tried both (60 and 240 Hz) on the same system.

60 was slightly more jittery than 240 (but not horrible).

Either way, I'm nearly 100% certain that the refresh rate wasn't the major differentiator.

I think OBS vs ShadowPlay (as ShadowPlay seems more optimized), plus Nvidia Optimus being enabled were the main culprits.

That said, there was a perceived degradation with 60 Hz (as 240 Hz is native for the laptop).

There was also a perceived degradation with 1080p (as the 2160 is native for the laptop) as well.

As long as it's now fixed, I'm good.

Thank you for the help.

Regards,
Nelson