HOW can I view avi files on Ipad

My security cameras send an email with an avi file when motion is detected. I can easily view these on the imac just by openimng the attachment ( Quicktime is opened and the files converted for viewing).

I can't see how to do this on the ipad and iphone 5. I've tried downloading things like AVIPLAY, but I don't knwo how to detach the files for them to convert...and I don't know how to make them be invoked automatically. I'm looking for a straightforward solution similar to the one I get on the imac.

Thanks

Peter