That's not entirely true. We currently use taglib-sharp to read MP4 tags. The only tags we read though are title, sort title and year. We currently don't extract images from MP4 files but as far as I know it should be possible with before mentioned library.There is no free open source tool to read the tags from the MP4 format. Available are only some modules written in Pearl, Ruby or Java, none of them are usable inside MediaPortal 2 (written in .NET).