basically, if your data was encoded on a per byte basis, then it doesn't make much sense treating it as unicode before it was decoded.

You should transform it back per byte and then treat it as unicode (if necessary)

And posting your data into HTML doesn't really help!

try something like

  DB<200> $str=join "","äöüÄÖÜß"

  DB<201> printf '\\x%X,',$_ for unpack 'C*',$str
 => ""
\xC3,\xA4,\xC3,\xB6,\xC3,\xBC,\xC3,\x84,\xC3,\x96,\xC3,\x9C,\xC3,\x9F,
[download]

or even

  DB<202> unpack 'H*',$str
 => "c3a4c3b6c3bcc384c396c39cc39f"
[download]

this should already be a strong hint on how to solve your problem ...

Thank you!