DVD's

[giles.enders]

Not sure if any one here can answer this but I have many DVD's with excellent sound quality PLUS I have the pictures too.  The playing time is mostly up to three hours.  Why then do CD's only have a playing time of up to eighty minutes. I know I will be told technology but I suspect there is more to it.

[Delicious Manager]

It is to do with the encoding. CDs contain more complex, condensed information on two levels (notice how your DVDs pause momentarily when they change layers?). CDs are much more simply encoded (therefore, less playing time). That's why you can play a CD on a DVD player, but not a DVD on a CD player.

[Mark Thomas]

A bit of a non sequitur perhaps, but the maximum running time of a CD appears to have been determined by the length of Beethoven's Ninth. See here.

[Delicious Manager]

This was in the very earliest days of CD. Manufacturers used to claim that 74 minutes was the maximum playing time that could be burnt to a CD. Beethoven 9, being around 64-68 minutes' duration was a useful example for people to give as the optimum length for a CD. The reason for the shorter playing time was the non-availability of digital master tapes of a suitable length from which the CD master could be produced (don't ask me why; I don't know). However, as the medium boomed, longer master tapes became available and it is quite possible to have CDs of 81-82 minutes in length (I have a couple myself). There have been CDs produced with up to 90 minutes of information squeezed onto them, but many players won't read these properly as the information is stored too close to the CD's outer edge.

[TerraEpon]

Robery van Behr of BIS claims the absolute maximum is 82:30. The first box of The Sibelius Edition has a disc that's 82:27 (and it shuns BIS's typical 20 seconds of silence at the end(

[Paul Barasi]

While we're at it:

(1) Wot's wong with CDs using both sides for double capacity + have any been issued that way?

(2) Is there any logical reason for CDs and DVDs having different sized cases (other than the feeble explanation of product recognition)?

[Delicious Manager]

While we're at it:

(1) Wot's wong with CDs using both sides for double capacity + have any been issued that way?

(2) Is there any logical reason for CDs and DVDs having different sized cases (other than the feeble explanation of product recognition)?

1) It doesn't leave much space for LABELLING if CDs are double-sided (where would YOU put the label?). And is there an advantage? Multi-CD players will happily play one CD after another, but I am not aware of one that could turn one over and play the other side.

2) Most packaging is stupid. The plastic CD jewel case is one of the abominations of the 20th century (give me a sturdy digipack any day). And to put a single DVD into such a large case is ludicrous. A huge waste of shelf space.

[Hofrat]

A bit of a non sequitur perhaps, but the maximum running time of a CD appears to have been determined by the length of Beethoven's Ninth. See here.

Beethoven also had a hand in the setting of the 33 1/3 RPM speed in the LP era.  That was the speed needed to record Beethoven's 5th symphony on one side of the LP. 

[Delicious Manager]

A bit of a non sequitur perhaps, but the maximum running time of a CD appears to have been determined by the length of Beethoven's Ninth. See here.

Beethoven also had a hand in the setting of the 33 1/3 RPM speed in the LP era.  That was the speed needed to record Beethoven's 5th symphony on one side of the LP.

I'm afraid this is incorrect. While there WERE a very few LPs which managed to squeeze Beethoven's 5th Symphony onto a well-filled single side (it is always something just over half an hour - that's a LONG side for the old LP). I would say that 95% of the recordings of Beethoven's 5th I have ever encountered have only the first TWO movements on side 1, with movements 3 and 4 (and perhaps a filler overture) on side 2.

[giles.enders]

I have some double sided DVDs but it is not easy to know which side is which and as has been stated, it is useful to have some information on one side, just in case the disk is separated from the case. 

If one has good equipment is there really any noticable difference to the quality of sound between a CD and a DVD?

[TerraEpon]

There's also the 'Dual Disc' I believe it's called, which is a CD on one side, and DVD on the other.

[Paul Barasi]

A double-sided CD could use the centre circle for information on contents, including saying side 1 or 2. After all, printing on one side of the page isn't considered green these days, so why should using just one side of a CD be acceptable?

[TerraEpon]

I actually recently bought a 2 disc set of Schubert's late sonatas and disc 2 had an extra disc stuck to it....it was the same disc but with no label on the other side at all.
Ok that's not really related to anything, but if you wanted to make them different one would have to etch the disc number into the plastic or something...