[quote user="FlintyGull79"]Can Xbox One play AVI format DVDs and Blu-Rays???[/quote]We don't know what file formats are supported at this time. Normally it's not just the container that matters, but the specific compression used as well.[quote user="Unreal
Warfare"]Blu Rays are .mkv format.[/quote]".mkv" is just a container format (Matroska). "Blu-ray" is also a container format, after a fashion. Several different video compression standards are supported,
including MPEG-, MPEG-4, and VC-1.
[quote user="FlintyGull79"]if I own a DVD movie that's in AVI format[/quote]There aren't any. AVI on a DVD disc would just be an AVI file burned onto a DVD disc. Retail titles would not be sold in that manner.