External data source simply need to provide the strings in the encoding used on your local system (presumably UTF-8).
Klaus
This is what I did in my xmltv grab process:
iconv --silent --from-code=ISO-8859-2 --to-code=UTF-8 --output=/opt/tigervdr/xmltv/hu-utf.xml /opt/tigervdr/xmltv/all.xml
And this provides vdr the correct encoding for epg.