I recorded 31 hours of MPEG4 only, and it says 5% available. Mostly network prime time dramas, Leno and Letterman. I have only HD programs- nothing with a lot of action.-no reality-no SD, no MPEG2. I noticed this before, so I reformatted, and forced a new software download. I have Dolby digital turned on. I have verified no recording is longer than expected. Is it possible I have a smaller hard drive? Or is it possible what I assume is MPEG4 is really MPEG2? How can I tell? Are the MPEG4 locals next to the standard def channels in the Guide, or are they up on higher channels? I now have, (with the last software release) no other problems with the HR20, that I know of.