Question about recording GoPro

[Trancelistic]

Hey. This bothers me over 10 a 16 years orso. (windows pc with fast FPS games)
But now also withGoPro.

If I upload the full GoPro video to youtube. Its all fine.
Its cap't at 60 FPS because more is not needed.
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But If I want to be lasy and capture a part of that video using VLC or Media player etc with Bandicam dragged window to record.
its all stutterish.. (Note in the Bandicam options the HZ or FPS is the same as the video, its synced)
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How come?
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Change the Resolution or FPS from 3k to FULL HD or FPS /HZ from 60 to 30hz It makes no difference. The video is stutter ish..And yes, I matched the Bandicam options to adjust that FPS or Hz.)

I can't be my system specs. I run a 64gb AMD Ryzen 9800x3d with a Nvidia 4080super.
Also my Other pc Who has 32 GB of DDR5 who is dual on 6000 mhz with a 7800x3d and a RX9070XT does it too.

I've tried every bandicam codec. Its just not smooth..

Any idea whats going on and how to solve it?

Ps: I also Got an old I7 4790k with a GTX 1080. All is fine and fast. but on that system it seems to be smooth.. Weird eh..An older system does it better.
Edit: Also tried it on my friends pc who has an Intel i9 13700k along with a RTX 5070ti.. Same stutterish thing.

Note All 3 pc's are running the same windows 10. (But my friends i9 pc. That is on win11.

Extra Info I even got an old 2008 laptop. or i used to had it. Screen was 1920x1200 with some nVidia Quadra card of 512mb along with a only a dual CPU (Intel T9800 and 2x4 GB DDR3 ram.
And i remember that bandicam was fast and smooth as hell on that one. (games then, never tried it on Gopro but video's on VLC etc.. Perfect... it was just perfect.

[Bandicam Company]

Hello,

Since you told that the same issue occurs on multiple high-performance PCs, we would first like to determine whether the issue is related to the video playback or Bandicam recording.

Please try the following:
1. In VLC, set Hardware-accelerated decoding to “Automatic” under Tools → Preferences → Input / Codecs, and then record the same GoPro video with Bandicam.
2. In Bandicam, please use Screen Recording mode → Rectangle on a screen and record only the video playback area.
3. Please set Bandicam to 60 FPS and use the H.264 (NVIDIA NVENC) codec if you are using an NVIDIA GPU.

After recording, please check whether the recorded video is still stuttering.
If the issue persists, please send us:
1. A screenshot of your Bandicam Video > Format settings
2. A short sample of the original GoPro video, if possible
3. A short sample of the stuttering recording

Based on these results, we can investigate the cause further.

Thank you.