Re: Disc ID Calculation

robert nospam at moon.eorbit.net
Thu, 18 Mar 1999 14:18:39 -0800 (PST)

On 18 Mar, Peter Bierman wrote:
>> 2) Instead of having one frame offset for each track, there are
>>always 99 frame offsets. Any frame offsets beyond the ones for actual
>>tracks are fed into the SHA1 algorithm as "00000000" ASCII.
>
> What are you/we going to do when we have DVD-Audio discs with more than 99
> tracks?

This algorithm only works for audio CDs -- there is no relationship
between audio CDs and DVD-audio CDs. We will need to come up with a
completely different algorithm to handle those. DVD disks are CD-ROMs
with complete filesystem structures on them.

> Also, can someone explain why the hashing is used at all? Why not just use
> the binary representation of the TOC directly?

The hashing is used to have a nice consistent length key -- the TOC
data can get quite length.

--ruaok Freezerburn! All else is only icing. -- Soul Coughing

Robert Kaye -- robert nospam at moon.eorbit.net http://moon.eorbit.net/~robert