The fastest common video standard now is 4K at 60fps over HDMI. However this would require very fast capture equipment due to the high bit rate. One frame of 4K video has twice the width and height (4x total pixels) of a 1080p frame, with 3 color channels for RGB color. So you have 8,294,400 pixels * 60 fps * 3 color channels = 1,492,992,000 samples per second as the sample rate. Since it's digital video, if the bit depth is 8 bits per sample, that's a bit rate of 11,943,936,000 bits per second. This is about 12 GBits/s. If the bit depth was instead 12 bits per sample, that's a bit rate of 17,915,904,000 bits per second. This is about 18 GBits/s

While that is a VERY fast bit rate, it still is slower than the highest bit rate supported by the latest USB standard, which is called USB 3.2 Gen 2x2. According to this article https://www.tomshardware.com/news/usb-3-2-explained the USB 3.2 Gen 2x2 standard supports up to 20 GBits/sec which is more than fast enough to capture the 4K 60fps HDMI signal at 8bit or even 12bit bit depths. But I notice there's not USB 3.2 Gen 2x2 capture devices for HDMI on the market. The only capture device I found that actually allows recording 4K 60fps HDMI actually unfortunately is an internal PCIe card for desktop computers (so unusable on laptops), from Elgato. Yes, PCIe of course has the bandwidth needed, but so does USB 3.2 Gen 2x2. Why are there no USB 3.2 Gen 2x2 capture cards out there for 4K 60fps HDMI yet? It would physically be possible to do. Why has no company made one yet? Or at least I couldn't find one that did.

The only 4K 60fps HDMI capture devices I've found are ones that use shortcuts to use lower USB specs. One I found on Amazon said USB 3.2 but didn't specify Gen 2x2. If it's actually only USB 3.2 Gen 2, that's equivalent to USB 3.1 at only 10 GBits/s, and if it was US USB 3.2 Gen 1, that's equivalent to only USB 3.0 at 5 GBits/s. And these capture devices on Amazon clearly don't use USB 3.2 Gen 2x2 because they all show actual capture specs below 4K 60fps. They say they take in up to 4K 60fps but then state that it gets captured at the lower resolution of 1080p, so they use downscaling to keep the bit rate low enough to use a lower generation of USB 3 standard.

If anybody here knows of any company that makes a genuine USB 3.2 Gen 2x2 capture device for 4K 60fps HDMI, please let me know.