difference between commercial and home-burned DVDs

[nttaylor]

A friend of mine told me today that ordinary commercially released SS/SL DVDs of cinematically released movies, like the kind you get in the mail from Netflix, actually contain more than your standard 4.7 G of data, but that it is currently impossible for the home user to burn DVDs of this type.

This, he said, is because Hollywood power brokers want to make sure that home users can't copy their movies. According to him, the methods used to produce commercial DVDs, which are different from those used by someone burning at home on a computer, are what makes it possible for the studios to put more high-quality video and audio on a disc. The at-home burner is therefore stuck with an externally imposed limit that forces him to make DVDs with either a lower bitrate or a shorter duration than what the studios can make.

I've been doing lots of reading for a couple of months now as I've tried to educate myself in the subject of creating DVDs, but this is the first time I've heard of this.

So, is it just a rumor? Is it true? My googling has so far turned up nothing.

nttaylor

[setarip_old]

Hi!

Misinformation!

Yes, the methodology of producing commercial DVDs (PRESSING) is different than the methodology you and I use (BURNING), but - since about two years ago, DOUBLE-LAYERED burnable media and burners capable of burning such media have been available to we consumers, so that we are capable of burning full 1:1 copies of "D/L" commercial DVDs...

[PuzZLeR]

Almost all commercial DvDs are over 8.5GB in size. This means that you can add more bitrate into a 2 hour feature for all that extra quality.

When consumer "blank" DvDs became available, they had a max capacity of 4.7GB. Not sure if this was due to tech limitations back then or an effort by the movie groups to prevent copying, but this obviously meant that if you wanted a copy of a commercially available movie you had to "squeeze" its data down to fit, which would require major processing power (back then) and you would surely lose quality quite noticably. That is, if you were able to remove the encryption beforehand as well... How's that for discouragement?

Late 2003 the blank DvD-DL, which has that 8.5GB capacity, became available to the consumer market, such as setarip_old mentioned. Yes, physically a printed/pressed commercial disc is different from something "burned" onto a blank. The commercial ones are more solid, while the burned discs have higher risk of data loss and long-term retention is weaker due to their internal dyes which are more likely to "shift". It is their ability to physically have data burned into them that is also the reason they may be less stable.

However, digitally there is no difference. Data is data. If the exact data fits, as it should with a DvD-DL, there is zero loss of quality. In this case it would be a direct copy, not a "shrunken" version.

Hope these posts solve the mystery on your end...:p

[nttaylor]

Hi setarip_old and PuzZLeR,

Thanks for the responses, though the truth is disappointing. But isn't it the case that even with DL discs, the home-user is still unable to produce studio-quality DVDs that will be universally viewable because the great majority of DVD players can't handle dual layer DVD-R or DVD+R, right? Of course, the ideal would be the ability to put 8.5 G of data on a single-layer disc readable by any run-of-the-mill DVD player. As of now, is this still a pipe-dream?

[setarip_old]

though the truth is disappointing. But isn't it the case that even with DL discs, the home-user is still unable to produce studio-quality DVDs that will be universally viewable because the great majority of DVD players can't handle dual layer DVD-R or DVD+R, right?No - you've already been answered - and there's nothing disappointing in the truth...

[foxyshadis]

If you can bitset, you're golden; if not, then it's a bit of a crapshoot. The physical reflective properties aren't enough to mess with any but the weakest players, or ones that are slightly out of alignment already.

[CWR03]

Of course, the ideal would be the ability to put 8.5 G of data on a single-layer disc readable by any run-of-the-mill DVD player. As of now, is this still a pipe-dream?
It's not pipe dream, it's just not possible. You most certainly can put a full, commercial DL DVD onto a burned copy with no compression and have it play in "the great majority" of standalone units, if you choose the right media and burn with bitsetting enabled as foxyshadis mentioned. But you can't put 8.5 GB on a single layer disk because of the physical limitations of the burner, player and media.

[blutach]

All this being said, nttaylor, you should aquaint yourself with transcoders and encoders. A simple easy to use program for beginners is DVD Shrink - it does what it says, shrinks dual layer DVDs to single layer ones.

Higher quality can be obtained by using an encoding solution - DVD Rebuilder (http://dvd-rb.dvd2go.org/) is the tool of choice here IMO.

And if you decide not to re-encode/shrink, when burnng DL disks, please do remember not to buy anything other than Verbatim +Rs DLs.

Regards

[nttaylor]

Regarding setting the bitrate, I'm using TmpGenc DVD Author for burning, so I do have control over that.

blutach, I'm interested in your endorsement of the DVD+R standard. In fact, I actually burned my first DL disc last night, and I went out of my way to buy DVD-R DL discs and had to get a new burner to boot. I was under the impression that DVD-R DL was slightly better supported. Is that false?

The impression I'm getting from this forum is that most players should be able to handle DL discs, but the one I burned last night wouldn't play in my player (a Philips DVP642). In fact, it wouldn't even play in the drive I burned it on, which doesn't make much sense. TmpGenc exited cleanly so I don't have any reason to think there was an error in the process, but maybe it didn't work.

But maybe I should just forget about DVD-R for DL discs. blutach, let's assume I'm not interested in re-encoding or shrinking at the moment. Why do you recommend DVD+R DL over DVD-R DL?

[blutach]

I was under the impression that DVD-R DL was slightly better supported. Is that false?
It is very false. For technical reasons to do with the layer break and the requirement to burn to the edge, -R's do not make good DL disks (there have been many threads on this - search the forums). Here's one (http://forum.doom9.org/showthread.php?p=855113#post855113).

Only buy Verbatim +R DLs.

Regards

[Soulhunter]

When consumer "blank" DvDs became available, they had a max capacity of 4.7GB. Not sure if this was due to tech limitations back then...

Yes, its was... Even the first commercial DVDs I bought were 4.7GB [or more like 4.5GB if you dont calculate like the storage media producers, lol] single layer discs... But they were double sided, so you had to flip the disc in mid of the movie!


Bye

[PuzZLeR]

Yes, its was... Even the first commercial DVDs I bought were 4.7GB [or more like 4.5GB if you dont calculate like the storage media producers, lol] single layer discs... But they were double sided, so you had to flip the disc in mid of the movie!ByeHey Soulhunter. Yes, this 4.5 and 4.7 thing is because of two different types of storage units, and used for propaganda purposes by several companies...Thanks for clearing the tech limitations thing. Flipping a digital disc sounds an awful lot like those laser-discs of a few decades ago - currently eBaY domain now...

[CWR03]

Yes, this 4.5 and 4.7 thing is because of two different types of storage units
Huh? This 4.5 and 4.7 GB has to do with manufacturers calling 4700 MB "4.7 GB" when in reality a GB is 1024 MB, therefore 4700 MB is technically 4.5 GB. It's terminology and has nothing to do with any type of storage units.

[blutach]

And as we all know, it is actually 4.37Gb, or 4482/4489Mb (depending on whether you like + or - blanks).

Regards

[PuzZLeR]

Huh? This 4.5 and 4.7 GB has to do with manufacturers calling 4700 MB "4.7 GB" when in reality a GB is 1024 MB, therefore 4700 MB is technically 4.5 GB. It's terminology and has nothing to do with any type of storage units.Agreed. Didn't state it correctly. :o You can tell I was an awful computer science student...now my brain hurts...:confused:

[HyperHacker]

Yeah, if there's one thing that annoys me, it's that storage device manufacturers can get away with calling a 233GB disk "250GB". -_- Why aren't the standards people all over this? It's even worse with flash chips, when "64M" means 64 megabits or 8MB. Nobody measures in megabits...

PuzZLeR, the problem is simple: manufacturers use metric (1KB = 1000 bytes, 1GB = 1,000,000,000 bytes, etc) while everything else uses binary (1KB = 1024 bytes, 1GB = 1024 * 1024 * 1024 = 1,073,741,824 bytes). Metric makes a bit more sense, but binary is a well-established standard used in about 99% of software in my experience (and when they do use metric, they use the proper terms KiB, MiB etc).

[Mug Funky]

the only commercial discs that can't be perfectly 1:1 copied are PTP discs.

DVD+R DL is OTP only (not PTP), and DVD-R DL is balls and doesn't allow a layer break at all.

if you want to copy one of these discs without transcoding you have to re-author it and shuffle around some elements like trailers or menus to make the first layer bigger than the second layer. this is pretty tricky, and it's usually just easier to either re-encode the credits or ditch one of the special features (which aren't that special most of the time anyway... more like space filler or some director's self-indulgence).

there's no PTP conspiracy though... it's usually just sloppy or hurried authoring if you come up against one of these discs. they're quite rare.

Almost all commercial DvDs are over 8.5GB in size. This means that you can add more bitrate into a 2 hour feature for all that extra quality.

bollocks. no DVD is bigger than 8.5 gigs. and even if it was, you'd not be able to get any extra quality at all out of 2 hours of footage - 120 mins on a dual layer disc will hit the max bitrate. you can't go any higher even if you have the space for it. nothing higher than 9.8mbps sustained or 10.08mbps instantaneous. otherwise your player will stutter (but no decent authoring program will even let you import or compile a feature that high).