USB-c to hdmi on pi 400 failure

My son purchased a usb-c to hdmi video capture cable so he could use his usb-c enabled tablet as a screen for his raspberry pi. This technique had been proven to work by others, via a usb camera app. But despite the the usb-c to hdmi video capture device stating it can support up to 1080p picture quality/size, it seems to only support 720x480 picture quality/ size. When you try a higher picture quality it glitches and fizzles.
We would really love some support on this, thanks!

Hi Bron,

HDMI is a tricky beast - There are 86 “modes” (resolution, refresh rate and more) that a device can support, and it may be that your Pi cannot output in the format that your capture card supports.

It could also be that your tablet’s USB port is 2.0 only, so the 480Mbit/s bandwidth is not enough to fit higher-resolution video through.

Have you tried the capture card on a known 3.0 port? Like one marked with “SS” or “SS10”(Gbps) on a full-size PC?

If you want an enclosed monitor for a Pi, we do have tablet-sized options:

Hope we can get to the bottom of this one with you!