[Flac] Tag Clean-up

[Stuart Neill]

My music collection is now all made into flac files. However I appear to have 
bungled when encoding about 1/3 of the collection by applying ID3 tags rather 
than vorbis/metaflac comments. In some cases, I seem to have applied both.

Also rather late in the day I started applying 
replay gain when encoding. I'd now like to remedy the situation.

An Internet search shows up lots of scripts for transcoding the file formats 
but few for transcoding the tags, a bit of a surprise to me as I believe older 
flac files would have used ID3 tags.

Does anyone on this list have, or can point me to, a script which would 
recursively go through my music collection and replace the ID3 tags with 
metaflac comments while ignoring files which have been properly tagged?
 
Similarly, I'm looking for a script to apply replay gain where missing. On the 
subject of replay gain, I'm assuming that the values applied when writing the 
ID3 tags are the same as would have been applied to the metaflac comments. Is 
this correct? I've been using Grip to do the encoding.

-- 
Stuart Neill