Yes it has various access points e.g. usb, Sd card, it played one movie then would not play other which was of a larger size?
Interestingly, I can't seem to dig up much info on this feature. Random references in other discussions, but nothing too specific. Well the problem could be any number of things. The file may simply be too high a bitrate for its software to handle, or it may not support the video or audio codec contained in the mkv file. Just to elaborate on that last part… an mkv file is a container, much like a zip file, and the actual audio and video components inside it can vary. The video itself could be an MPEG2, MPEG4, and others. The audio could be AC3, DTS, MP3, AAC, and so on. The TV's playback software may be able to handle an MKV file with MPEG4 video but not MPEG2. Perhaps AC3 but not DTS audio.
I pulled up the owner's manual for the set and here's the relevant media requirements:
• SD-Video Files (SD-Video Standard Ver.1.3) Modified data with a PC may not be displayed correctly.
• AVCHD Standard compatible files Modified data with a PC may not be displayed correctly.
• MotionJPEG files (taken with LUMIX)*
• MP4 files (Video codec H.264 | Audio codec MP3/AC-3/LPCM)
• MKV files (Video codec H.264 | Audio codec MP3/AC-3/LPCM)
• MPEG-2 PS files**
• MPEG-2 TS files**
The items with ** after them means that they are only supported via the DLNA feature. If I interpret this correctly, then it only plays back Standard Definition media (i.e. 480p or lower), not HD. If you like, post the media details of something that plays, and something that doesn't. Load the video up in VLC, then press COMMAND-I to get a Media Info window. Under Codec Details, open each stream and post the information it gives.