SACD: How many minutes of audio per disc?

If a redbook CD can hold 79 minutes of audio, how many minutes of two-track stereo audio information can the SACD layer of a SACD disc hold?

Thanks in advance.

 

A 74-minute CD is 783MB of audio data. A 4700MB SACD disk could hold at most 6 times as much (4700/783 = 6).

 

Well, yes, but that's only of CD quality audio....I confess that--like the original poster--I don't really have any idea regarding SACDs overall capacity for DSD, as DSD is something for which the time/size ratio eludes me.

-D

 

Also, the rotational speed of SACD is higher, so the
relationship of time vs data rate we are familiar with
in the redbook format does not apply here.

Still it's an interesting question--any techies out
there care to expound?

--Roger

 

I did a search on the net, and found this;

http://146.215.65.91/sacd/features.htm

According to this article, 'For 2-channel stereo, this translates into over 100 minutes of recording capacity'.

 

Actually, it's possible to have up to 256 minutes! Here is a link to a reply by a guy who works with DSD and has for many years:

http://www.audioasylum.com/cgi/m.pl?forum=hirez&n=8220&highlight=maximum+length&r=&session=

Note: If I understand this correctly, this would not be a hybrid disc, but would be dual layered, and it would use the multi-channel area for stereo.

Also, this has more to do with the *possible*, not the practical. My longest disc is 82:00, Isaac Stern Plays Vivaldi The Four Seasons.

 

SACD not only provides for a dual layer (not hybrid) but also optional loss-less compression. Obviously a multi-channel/stereo disk can not play as long as a pure stereo disk, assuming the multi-channel section was used for stereo. But that would not work with stereo only players so I guess about 80 min is the max, but changes in compression technology could extend this I guess.

Richard.

 

Hmmm... I was meaning to ask here if it was possible to squeeze a double-CD title onto one SACD. Assuming only a two-channel mix, of course; something like the "White Album".

 

You can have 110 minutes of stereo on the SACD stereo area. But if it were a hybrid disc, the CD area would be limited to around 74 minutes.

In your example, "The Beatles" could fit on one SACD if it were an SACD only disc. But it would almost certainly be a hybrid, in which case it would have to go on two discs because of the time limitations of the CD layer.

 

From HiREZ Highway:

In principle, yes, assuming 6-channel + 2-channel equates to 4x 2-channel, you could put some 280 minutes of stereo on a single layer SACD, and since dual layer SACDs are possible you would end up with some 560 minutes of stereo on a single disc. Unfortunately, other considerations were taken into account when the SACD specification was created, and so the maximum length of a disc is limited to 256 minutes.

If that's the case, why is Hot Rocks a double disc?? Just to keep it like the original release??

 

Hmmm... I was meaning to ask here if it was possible to squeeze a double-CD title onto one SACD. Assuming only a two-channel mix, of course; something like the "White Album".

Does anybody seriously think we would ever see this on a single disc, even if it could simply be done?

 

I would imagine it is to accomodate the CD layer, which could not fit the entire Hot Rocks on a single disc.

 

Upon reading this thread last night, I went out and checked the Ozawa Mahler 2nd Japan-only Sony SACD, which is a fairly long symphony. It came in at 80:52. I also checked the Decca CD reissue of the Mehta performance of this work which came out to 81:12. I was somewhat surprised to see this, in that I had thought that Universal might have pulled some tricks to get the whole symphony on one CD, but in checking it against the timings for the original London 2-CD set released in the 80's, I found the timings were within a few seconds of each other.

My question to those up on the technicalities of CDs has to do with the upper limits on them - not SACD, CD. How did Universal get 81:12 onto their Mehta/Mahler CD? Is this common?

I'm not sure how long The White Album is, but I am wondering if it really is much longer than 81 minutes. If it's not, then, obviously it is released as a double set so that it can sell for more money.

There are numerous examples of double albums that appear on 1 CD: Electric Ladyland, Tommy, ALL recordings of the Beethoven's 9th (in fact, maybe some of you know that in designing the CD in the first place, Sony wanted to be able to put the 9th Symphony on a single CD) and the Allman Brothers Live at the Fillmore come to mind.

 

But if they could use this technology to the maximum, they wouldn't be able to justify charging you more, would they ? But then, they can come up with any load of crap to justify that, can't they ?

 

Yeah, it's all about money, mikenyc, I agree. But the question remains unanswered.

If SACD can pack so much more data onto a disk, then it could logically be deduced that once the pressing plants are up to speed the record labels could cut their manufacturing costs in half on especially long programs. Opera programs that were pressed onto more than 4 records could (and on as many as 3 CDs), based on some of the input above be reduced to two SACDs at most.

 

It may help them, but to believe that they would pass the saving onto the customer is naive.

 

There is a technique called "overburning" which allows for writing in a data only area of a cd

This is from: www.cdrfaq.org

The capacity of a CD-R is calculated to allow enough space to hold at least 74 minutes of Red Book audio data and 90 seconds of digital silence. The silent area is called the "lead-out", and is included so that a CD player will realize that it has reached the end of the disc, especially when fast-forwarding.

When a recording program tells you the exact capacity of the disc, it's not including the area reserved for the lead-out. There's nothing magic about this reserved area though. With the right kind of setup -- and a willingness to accept write failures as a matter of course -- you can put data into the reserved area, and possibly into a few blocks past the end of it. This is often referred to as "overburning" a disc.

How much more you can fit depends almost entirely on the media. Some brands will hold as much as 78 minutes, but it varies from batch to batch. You can use Feurio! (section (6-1-42)) to compute the maximum size of a specific disc without actually writing anything on it.

You also need the right recorder and the right software. The Teac CD-R55S, Plextor PX-R412C, Yamaha 4xx/4xxx, and Memorex/Dysan CRW-1622 units have been used to write "extra long" audio discs successfully. The Philips 36xx, HP 71xx, and Ricoh 62xx units don't seem to be willing to do so. In some cases, getting the firmware revision may be important. A recorder that isn't able to do this sort of writing will usually reject the cue sheet before writing begins.

To write such a disc, you need to use a program that won't refuse to exceed the disc capacity. Easy CD Creator, in an attempt to prevent you from making mistakes, will refuse to allow you to write more than you should be able to. CDRWIN will warn you that the write may fail, but will allow you to continue anyway. Nero has a preference (under Expert Features) called "enable oversize disc" that allows the longer write.

One approach to determining the maximum disc length is to gather a large collection of audio tracks, and start writing. Eventually the recorder will attempt to write past the end of the disc, and the write process will fail. Now play the disc, preferrably in a player that shows the total elapsed time for the entire disc. When the music cuts off, make a note of the time. That's the absolute capacity of the disc.

Most (all?) CD players will display the total disc time when you first put the disc in. This value represents how much you tried to write, not how much was actually written. If you want to impress your friends, try to write 88 minutes of music. You won't get anywhere near that far on 74-minute media, but the CD player will show it.

It should be possible to write a CD-ROM in the same manner as an audio CD, but the space would have to be calculated so that the write failure occurred when the lead-out was being written. Otherwise, some of the files that appeared to be on the disc wouldn't actually exist.

Recording in DAO mode may be helpful to ensure that the lead-in gets written. Without a table of contents, the disc is useless. It's very likely however that you will be able to finalize the disc even after the write fails.

Depending on the disc and your player, you may have trouble seeking out to tracks near the end of the disc. Also, your CD player may behave strangely when it walks off the end of the disc: one user said he had to open and close the player afterward to convince it that a disc was still loaded.

The disc surface past the end of the area reserved for the leadout may be unreliable. Attempting to use more than 90 seconds (about 15MB of MODE-1 data) beyond the rated capacity of a disc could be asking for trouble.

It's possible to perform similar tricks on 80-minute media. Experiments with TDK 80-minute discs resulted in a recorded length of 82:09. MMC recorders don't seem to like having the lead-out position any later than 88:29:74, but that shouldn't get in the way.

Further commentary and instructions can be found at http://www.cdmediaworld.com/ under "OverSize / OverBurn CD-Rs", including a list of recorders that are known to work and step-by-step instructions for using popular software.

 

Well, keep in mind the process for pressing CDs isn't quite the same as for burning them. CD-Rs have a pre-formed "groove" which I'm pretty sure is NOT there when glass masters are made.

I can't imagine them being very reliable, but I have seen 90 and 99 (IIRC) minute CD-R media.

I was surprised at the mention of an 81+ minute disc. I think companies are usually reluctant to press discs discs above 77 minutes or so - I think I only have one 79+ minute disc in my collection (The Who - Rarities). Not that they can't do it, but I guess more people have problems with them (so I've heard).

 

They are not going to allow you, more than they think you deserve...and especially, if it were general knowledge that a CD's capacity was more than 45 minutes...let alone, 79 minutes...there would be lots more people ripping discs, trading, downloading and "stealing" their own music...and with that these ***** Music Companies would be out of business...the skies, literally, blackened with their falling bodies !

And with them, some of these artists who rip us off too, with the multiple, generally useless, remasters, would be out on the streets...with their own ftp!

This crap really gets me steamed !

 

Thanks for the input, Luke. I'll have to take a look into the collection a little deeper, but to my knowledge the Mehta CD is the ONLY one to put the 2nd symphony on a single disk.

Are you saying that the reason the companies don't press more 80+ minute CDs is that most garden variety players would have difficulty with them?

 

Well...that's what I've heard, anyway. Then again, this was in regards to some Who CDs that maxed out around 77 minutes. The reasoning was that the record companies get more returns with longer discs. I really don't know if there is any truth to that or not, but...

 

What makes you so sure it's not general knowledge? Many people have cheap and nasty "TV hits" CDs that go over the hour. Many classical CDs, particularly the budget lines, are well over 60 mins.

Regards,
Geoff

 

I have used a few of the 99 minute cds but I have only been able to successfully burn it up to the 89 minute mark or so. The big problem is directly accessing tracks after about the 83 minute mark. But they do play. There are several burners that will burn a cd as long as 99:05 but good luck getting it to play in a regular cd player.

 

An SACD is not a CD and the overburning technique is not applicable. An SACD can utilize loss less compression, dual layers and expand into either the stereo or multi-channel sections to add room for a longer stereo presentation.

Richard.

 

"What makes you so sure it's not general knowledge? Many people have cheap and nasty "TV hits" CDs that go over the hour. Many classical CDs, particularly the budget lines, are well over 60 mins. "

Geoff, Just because it's here, doesn't mean it's "general knowledge".

I'm talking about the general retail customer that doesn't mind shelling out $19.00 list for a CD without flinching and have no idea how their Samsung CD player works, NOT people here. We are somewhat different and more discriminating about their CD purchases and what they play it on, or we wouldn't be in this forum, in the first place.

If the real buying public knew what was going on, there would be twice or three times as many people, ripping CD's, and Audiogalaxy and Napster would still be around !