How to use mbdump-cover-art-archive.tar?

This file is available on the musicbrainz public ftp site.

I want

release_group | cover_art_url

Is it possible to derive a mapping from release_groups to cover_art_urls? This maps release_group to some kind of cover_art id. Is the url somehow encoded in the cover_art table?

$ wc -l *
      14 cover_art_archive.art_type
 3138204 cover_art_archive.cover_art
 3380016 cover_art_archive.cover_art_type
       4 cover_art_archive.image_type
    8934 cover_art_archive.release_group_cover_art

$ head -1 cover_art_archive.cover_art
829358878	268158		17462125	1	2012-04-30 21:48:55.085782+00	0	image/jpeg	\N	\N	\N	\N