Salix OS

Salix 14.2

gst0-plugins-ugly 0.10.19-i486-2salix http://mirror.inode.at/salix/i486/extra-14.2/salix/multimedia/
vs
gst-plugins-ugly0 0.10.19-i586-1gv http://mirror.inode.at/salix/i486/14.2/salix/l/
-------
gst0-ffmpeg 0.10.13-i486-1salix
vs
gst-ffmpeg 0.10.13-i586-2gv

What is a difference between these ones ?

The zero series of gstreamer was replaced by 1.x (from Wikipedia). Those old versions are probably needed by the odd package as dependencies. They come from SBo rather than core Slackware/Salix repositories.