How do I play M2TS files that have been ripped from a Bluray disc?
You must set the preferred source filter (a.k.a. splitter) for M2TS files to LAV Splitter or Gabest splitter. You can configure your preferred source filters with the Codec Tweak Tool. Be aware that the content protection of the Blu-ray disc must be removed before you can play the files. You can do that with a tool such as AnyDVD HD.