Say I make a final NTSC DV video render of a project, but later put that video on the timeline and add a music track, and render back to NTSC DV (no changes to the video track). Am I taking any kind of re-compression hit there?

I suppose I am just from re-rendering, but with the Sony codec it problably wouldn't be noticeable on a TV. But technically - ? does interleaving the audio require touching the video compression?

Thanks,

Greg