Panasonic SA-HT680PL Service Manual page 11

Conventional
Even though DVD player is CD-R/RW compatible, the inconsistent ways
that various DVD players can read the music or photos files often leads
to a confusing and inconsistant playback experince.
HighMAT compatible products play content back with consistent
interface. This includes products which are JPEG compatible products
without HighMAT support.
11
HighMAT
SA-HT680PL