[Ham-Computers] RE: VHS to DVD

[Hsu, Aaron (NBC Universal)]

Every recordable DVD disc has a "signature" specifies it's max write speed, what the medium is composed of, the total number of data "blocks", etc. - basically the tech specs of the disc itself.  The drive uses this information to optimize the write "strategy" used during the burning process.  Higher speed media requires a different write strategy than lower speed media.  The write strategy can also be different based on the formulation of the medium.

DVD recorders (stand-alone as well as PC-based units) have a burn strategy table in firmware.  It uses the data in the disc's signature and correlates it to a strategy in firmware.  If it doesn't find a match, the drive rejects the disc as it doesn't know how to handle it.  PC-based recorders usually have upgradable firmware to handle new disc formulations (or better strategies for writing existing formulations).

There have been problems with backwards compability of DVD recordable media.  An example is when 4x DVD discs became available.  Because older 1x and 2x drives did not know how to handle 4x DVD's, they literally self-destructed when they tried to write a 4x disc.  Pioneer posted warnings to drive owners not to use 4x media in 2x drives to prevent drive destruction.  Newer drives now either eject or prevent the use of non-supported media for safety reasons...this is most likely why your recorder doesn't like 16x media - it just doesn't know what to do with it.

Best thing to do is to check your recorder's manual and see if there is a recommended media list - then stick to it.

Happy New Year & 73,

  - Aaron Hsu, NN6O



-----Original Message-----
Sent: Tuesday, January 02, 2007 5:45 PM
Subject: [Ham-Computers] VHS to DVD

I have been preparing to move some ham VHS tapes to DVD but there is something that I do not understand.  My new Emerson DVD/VHS recorder seems to not like DVDs that are the 16X speed I find in all the stores; a friend told me that for some reason certain machines will only accept 'slow' DVDs so I tried an old 4X and the machine accepted it instantly.  I though the 'faster' media was back compatible, so what is going on here?

Color me Confused in California

John
WB6BLV at inreach.com