thanks for the idea fooze. I tried VMix (which is impressive for mixing multiple video sources and is targeted for live video production). Indeed, it does have the ability to re-encode my video file of concert footage and introduce a fade-out right where I'd want one. And the price is right (free version avail). However, the version of VMix I trialed could not preserve the multi-channel audio from the original source. It down-sampled the audio to 2-channel stereo without much selection for controlling other audio characteristics).
For MC 21, I got this far...
1) rip Concert DVDs with multi-channel audio (AC3 / DTS)
2) import into MC 21 library as a 'whole' concert
3) divide the video concert into individual songs using Particles (see
http://wiki.jriver.com/index.php/Particles )
4) add some of the particles to a "Multi-channel music" Playlist containing a mixture of different video concerts and audio files
Then I set my Player | PlaybackOptions | Audio | Track Change to the "Gapped Fade 5 seconds" setting. (There's no such setting for Video Playback).
Currently, when I play the playlist, the audio media gets a nice face to silence before the next track plays. But if the track is a video, the video media doesn't fade and ends sharply at the end of the Playback range.
So, my quest to have a way to fade out a video file without having to hard-edit the track itself.
My quest continues....