Pi Zero Virtual file system on USB Mass Storage Device

Question

I want to build an application (node.js, python, c, I don't care) that sets up a virtual file system like FAT32 or NTFS. Next, I want to expose this virtual disk through the USB Mass Storage gadget of the Pi zero.

What I really want is my HDMI capture device to write an mp4 to a USB stick (plugged into the capture device). I want my capture device to write to the virtual Mass Storage Device of the Pi Zero thinking it's a regular USB stick. Instead of writing a file I want the bytes to be piped directly to my application. This way I can process the captured video as fast as possible.

Does such a set-up exist? If not, what are my options?

Answer 1

This not really an answer to my question, but rather to the underlying question. All I wanted was to process HDMI images. I thought it was impossible but apparently the Auvidea B101 can capture HDMI directly to the Pi: https://auvidea.com/b101-hdmi-to-csi-2-bridge-15-pin-fpc