Lossless Conversion of Muxed MPEG Files to Quicktime

Many video editing and playback programs do not like "muxed" MPEG files, where the video and audio tracks are interleaved. For example, the MPG video clips captured by my Sony still camera are in muxed MPEG-1 format. If they are played back by Quicktime player or imported into iMovie, the audio is completely lost.

MPEG Streamclip can convert muxed files directly into Quicktime movies that play back properly, but this conversion re-encodes the video, so it is slow and loses quality. The better and faster way is to a two-step process:

1. Open the clip in MPEG STREAMCLIP, and select "Demux to M2V and AIFF". This will create two files, a video-only MPEG file and an uncompressed audio file. If your original is name movie.mgp, the new files will be named movie.m2v and movie.aiff.
2. Open the M2V file in Quicktime Pro. When you do so, Quicktime will automatically open the corresponding AIFF file as well, as long as the two files are in the same directory. Now do a "save as" a new Quicktime movie, making sure the box "make a self-contained movie" is checked. This will copy the data from the M2V file and the AIFF file into a new MOV file in Quicktime format. Note: do not do "export", do "save as"!
3. Now you can throw away the MPG, M2V, and AIFF files. The new MOV file can dragged into iPhoto and/or iMovie.