Conference cookie::notes$archive:cd_v1

Question:

I have always assumed each CD has a directory "in front" that contains
the index to the rest of the disk, as well as possibly other
information.  Has anyone ever seen what format this info is in? 

I'm quite curious as to whether they put text in describing the artist, 
mfg, album title, track titles, etc; and whether they were bright enough 
to use ASCII plaintext.

Has anyone tried putting an audio CD in a CD-ROM player and searched for 
ASCII?

Wondering...
_______
Richard

    Resurecting a long dormant subject...
    
    I'm currently looking for a CD player, one piece of info about a
    the philips 783 (? not sure of exact model number) intrigued me.
    
    It has a feature called FTS or Favourite Track Storage. You can
    store information in a non-volatile memory in the player about your
    favourite tracks for each disc you have (it seems to have enough
    space for info on up to 500 discs). 
    
    This begs the question, what's on the front of a disc to uniquely
    identify it. The salesman rather lamely (pity really as he was quite
    good on the audio side) tried to explain that it worked on the
    probability of more than one disc containing exactly the same number
    of tracks, and times of tracks. I don't buy that: it has to be some
    unique identification possibly in a 'label' area on the disc.
    
    Anybody got more info?.
    
    Richard

    I've worked with an external interface to a CD player before, and
    I don't believe that there is any "Hidden" Information to uniquely
    identify a CD.  Using the number of tracks and length of those track
    (in order) seems like a good and clever way to identify them to
    me.  Without sitting down to figure out the exact probablity, I
    would guess that the chance of two CD's (even out of hunderds) would
    have the same number of track, the same length, in the same order
    would be *very* small. :-)
    
                              
    Todd

    I would have agreed with .3 if it weren't for an experiment I did
    when I first got my Magnavox(=Philips) 650 last fall.  I had a regular,
    store-bought copy of Sting's 'blue turtles' CD, and a friend of
    mine had one that he had gotten through the CBS disc club.  Both
    disks have the same total time, same number of tracks, same serial
    number, and, to the best of my knowledge, the same number of seconds
    on any given track on both discs.  However, the machine did *not*
    recognize them as the same disc.  I don't really know what they
    use, but I just assumed that there must be some numbers on there
    somewhere, like a label number or something.
     
    		Steve

    I am given to understand that every disc has an identifying number
    encoded in the "index".
    
    				Steve

        ...but is it 12 hex digits starting with 08-00-... :-)

    I got the same line from a salesman when I got my Sony CDP-C70,
    that the 'uniqueness' of a disk was derived from it's number of
    tracks and total time on the disk, but then I've also heard that
    there's a unique 'serial number' on the disk.  Maybe there's a unique
    number but no-one pays any attention to it?
    
    Willie

I'd be amazed if there were no field in a CD earmarked for a unique 
disc ID, but I would be not surprised at all if there was no central
office responsible for registering IDs.
At best, it could be like product UPCs or book ISBNs, but we have an 
international market that might be very hard to coordinate.
(Well, books are international too, but we have fewer computer-based systems
reading and cataloguing books than we have CD players.)

Not being able to guarantee that all discs would have unique IDs,
player manufacturers might adopt a hack like tracks+playing times
as a local solution.

- tom]

    While we're talking about times of tracks, etc, stored on CD's -
    why is it that the actual playing time of a track as read from the
    display on the player very rarely corresponds to the playing time
    given in the liner notes? As the playing time on the display is
    picked up directly from data recorded on the disc, not an independent
    timer, why do they not agree? Surely the liner notes could be compiled
    using the "actual" figures?
    
    Now I've started thinking about it, I'm not sure if the track timings
    picked up from the index (which I guess are the ones displayed while
    programming) actually agree with the track timings stored along
    with the music - anyone noticed?
    
    I first started thinking about this when I recently picked up a
    disc where the liner notes said that due to differences in players,
    displayed times could differ from those given. But my player reads
    times from the disc - don't they all? Proof must be that on some
    classical recordings there is a count-down to the start of the music,
    presumably to give greater inter-track separation, and this can
    only be read from the recorded data stream.
    
    Would anyone care to comment on these inconsequential ramblings?

    I've set my player to display time remaining on a track.  Sometimes
    the time will go to zero when the song ends, sometimes there is
    a couple seconds left on the display.
    
    On the discussion of liner notes.  One example for a difference
    I can think of is Blood, Sweat, & Tears Greatest Hits.  The CD
    uses the liner notes from the album, but a lot of the songs on
    the CD are longer versions - An added verse, or a long solo.
    Some songs were more than a minute longer than the liner said.
    
    -Dave

    Different masters = different times.
    
    I have a "made in Canada" version of the latest Sting who is 1 second
    shorter than the U.S. Version. (Total disc time)  I beleive the
    masters make some difference, so when they print the liner, they
    cannot hit the exact right time.
    
    Vince.

    I haven't actually checked this out on a disc, but I was once told
    that the "negative time" that sometimes is included at the beginning
    of tracks is often counted on the liner time (and, or course, it
    takes real time to get past when the disc is playing) but that players
    don't count this "negative time" when they display the total time
    for the disc.  I'll check this out sometime, but if someone else
    is in a hurry to know, please check it out and tell the rest of
    us.
    
    B