I am looking for a way of displaying an analog video stream on an android phone. On a pc/mac/etc you can achieve this using a cheap usb analog-digital converter such as a grabby: http://www.terratec.net/en/products/Grabby_82248.html, and then view on VLC, for example.
Would such a thing work (in theory) on android if the proper drivers were available? (ie. are there any hardware issues which make this impossible?)
Does anyone know if such a device with android drivers is available?
Ultimately I want to make an app which interfaces with the grabby (or similar device) and allows the user to view video on the android and capture and send short clips.
First of all the Android device needs to support USB Host. This limits your userbase significantly.
Then there is the problem with power. Some USB Host devices will be incompatible simply because an Android phone will not be able to push enough power through to port to get it running properly.
I'm not sure about the drivers, but I'm 99% sure it won't work "out of the box".
You should certainly take a look at THIS project. It is pretty similar to what you are trying to do. Maybe you should consider getting in touch with that person.
EDIT: Based on what it took to get that DVB-T dongle running in the project i mentioned above the chances of creating an app that everyone will be able to simply download and use are EXTREMELY slim. Getting that dongle running required using a modified kernel and special scripts. Of course I could be wrong. You can continue the research yourself or wait for someone with more experience than me to reply.