Bitt,

Thanks. I figured out what I have to do, but not how to do it.

My MP3s have APEv2 comment tags (supposedly, but tag&rename cannot see them even though it supports APEv2), that look like:

MP3GAIN_UNDO=+006,+006,N

I need to add a Vorbis comment to my Flacs that looks like:

REPLAYGAIN_TRACK_GAIN=-9.00000 dB

Where the value specified for replaygain is -1.5 times the value specified for MP3GAIN_UNDO. And of course this value is different for every MP3.

My situation looks not good. I really don't want to be dragged into studying APEv2 in order to write the code to do this...