Sony DRX-820UL Operating Instructions Manual page 24

you can only play back the disc in single-session (DVD+R DL/DVD+R/
DVD+RW) or single-border (DVD-R DL/DVD-R/DVD-RW).
Also, DVD-Video discs created with the drive can be played back on many
standard DVD players. However depending on the type of your player,
playback of DVD+RW and DVD-RW discs may not be supported.
Playback of DVD-RAM discs is only supported for DVD-RAM compatible
DVD drives and DVD players.
Further, because of the differences in quality and characteristics between
various DVD-ROM drive, DVD player, DVD+R DL disc, DVD+R disc,
DVD+RW disc, DVD-R DL disc, DVD-R disc, DVD-RW disc and DVD-
RAM disc manufacturers, playback may not be possible depending on the
combination. (Playback compatibility is not under warranty.)
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