I have a number of music videos I've downloaded ranging from 1920x1080 down to 480x360. They are all mp4. I want to use them to make a 4 hour music video to replay at HD thru a HTPC, so a file is the final output. 1) What program is best to string them together? Nice transitions would be a plus, but not necessary. 2) FCPX wants me to transcode them to Prores, but when I did a few (Prores uses ginormous amounts of space!) the audio seemed to suffer in a few of the transcoded videos. Would it be best just to use native format? 3) Should I transcode them all to the same mp4 format first with Handbrake? Any tips would be greatly appreciated! TIA.