Use an android phone as a monitor screen with AV-in wire? I'd like to use my phone instead of a TV as a small display monitor (with a cable, not wifi). I have a couple of devices which have AV out on them, what I'd like to do is show their output on my phone (for example a MFT camera, so i can use it as a video monitor without having any special apps controlling it, or for a baby monitor that doesn't have wifi, it could plug in and i could see the feed on the phone and take screenshots perhaps)?

Is such a thing possible? I have found the right cable on amazon (male to male, micro usb to mini usb) but i don't know if it'll just work? I have a Sony Xperia Z3 (f that makes any difference).
Use easy cap ... 
easy cap is generally used for fpv in multirotors which has also the same purpose as yours. It takes an av input and decodes it to give an output in the phone.
Check here..
http://www.amazon.com/EZ-Cap-EzCAP168-Capture-Software/dp/B008I679QG/ref=sr_1_1?ie=UTF8&amp;qid=1464120381&amp;sr=8-1&amp;keywords=easy+cap