dvd speed of packet writing (live file system)

A very interesting moment. If I use just the usual writing on dvd+-rw
(iso9960 etc), so I can find how change speed of dvd rw recorder. But if I
use packet writing aka live file system aka udf 2.1 so I can't find how
change speed of device.

For example I have dvd disk and this one is writed on 16x of speed. But not
for everytime. I can and not read such disk and can it only on the 4x or 8x
of writing speed.
The relevant trouble I have and on the Linux OS. I anderstand that the
packet writing is very new technology etc by maybe it's can made.

Thanks