I have a WD TV Lube Hub media center hooked up to my TV/surround system in the living room, and it's loaded with movies, all in mkv container, DTS or DD 5.1 sound. I've been using iVI Pro/iFlicks/Road Movie to convert them for iPad, using pass-through video conversion settings so they just convert the audio to AAC 2 channel and leave the video as-is, and re-container it. Very quick, and works a treat. Problem is, it means I end up with 2 copies of the same movie on the drive (1 with a DTS/DD 5.1 audio track, 1 with a 2 channel AAC audio track). Is there any of simply inserting the 2 channel AAC track into the existing movie file so it'll play on iPad? I don't want to simply use the AAC 2 channel version of the movie for everything and delete the other one, because if I decide to watch the movie on the TV in the living room I then won't have DTS/DD 5.1 surround sound.