Is 16x read the limit of DVD drives?

[Scarlet Infidel]

I rip quite a lot of dvds to put on my Archos AV400 to watch on the bus to and from school. Now that i have upgraded from an athlon xp to an overclocked pentium 4, i can encode the video at least twice as fast as before.

This heavily reduced encoding time has drawn attention to the irritatingly slow ripping of the vob files to the hard drive in the first place. My 8x dvd reader takes about 20 minutes for an average film.

I was considering upgrading to a new dvd drive (or maybe a dvd burner even though id barely use it) and want to know if its possible to get one that will read any faster than 16x or is that the limit of the format? Thanks in advance.

[Swafe]

Pretty sure 16 speed is the limit mate, otherwise the disks are spinning too fast and risk shattering

[Scarlet Infidel]

Yeah, i thought as much but wanted to make sure. Its always more fun to live life on the edge for marginal benefit...

[Steve]

A bit of googling suggests that 16x DVD reading occurs at roundabout 10krpm, roughly the same as a 52x CD, and 52x is the limit for CDs to prevent cracking and shattering, so that is indeed the reason, as suggested by Swafeman.

[javalord]

Your only alternative is the Kenwood True X drives , although I dont think they ever made a DVD based unit.

[Swafe]

Im not sure if they ever made it anywhere near the mainstream, but I remember Yamaha (I think) made, or at least prototyped a CD drive that read at 72 speed, it must have had 2 lasers and run at half the speed or something so the disk didnt explode but they made it, and CDs didnt blow up in it.

Mind you, when DVDs came along they probably just couldnt be bothered...

[Steve]

Yes there were drives with multiple pickup, but not DVD. They got too hot and were generally pants. Shame really.

[arthurleung]

You wouldn't want a fragment of a dvd flying towards your face at 250kph (roughly 11000rpm)

[autopilot]

Is it not also to do with speed limits with IDE interface? I find it hard to believe a properly balanced disk with a good 'spin up' and 'spin down' would shatter.

[arthurleung]

16X DVDROM reads at around 30MB/s max. There is even no need for DMA66/100.

[Scarlet Infidel]

I hadnt seen the multiple laser cd-rom drives reviewed before. Impressive. (note the 64.3x rating). If only they had this kind of technology for dvd drives. Ah well, 16x will have to be enough.

[arthurleung]

An alternative method is to buy a few dvdroms
You can rip multiple dvds at the same time if you want to fully utilize your processor

Multiple laser need a very complex controller to manage all the signal. I think the technology is here, but the controller is not capable to process at a higher rate than CDROM. 16X of a DVDROM have a data rate much higher than CDROM, but there is very unlikely a consumer-class controller that can handle 40+MB/s

[richard-wong]

lol, my dvd rom doesn;t realy at 16 speed at any given time, tho it is rated at 16 speed. lol the best it can do is 14 or 15 when i am really luck, and get the first rental dvd of the shop most of the time it reads at 10 and thats with its own ATA channel and mastering poor really

[badass]

Is it not also to do with speed limits with IDE interface? I find it hard to believe a properly balanced disk with a good 'spin up' and 'spin down' would shatter.

Why not? At 11000 RPM the outer edges of the disk are doing 60 Meters/second! - thats approximately 130 MPH!!!
Centripetal acceleration is 776 meters/sec^2 or nearly 80g.

Whichever way you look at it thats a hell of a lot to ask a cheepo disc to handle.

[Rave]

The Kenwood True-X drives were apparently very poor at audio ripping, they couldn't manage an accurate stream; to manage 72X speeds they relied very heavily on the extra error correction of CD-Roms. I don't know what level of error correction DVD films have compared to DVD-Roms, it might be the same.

[richard-wong]

error correction is the key imo, they have pushed the speed of dvd to the limit now. i think they are developing the next generation of optical disks with higher data density, can't remember what they were called. my professor was on the project and he mentioned it in one of his mathsectures, as he climaxed about these error detection algorithms. anyway, higher data density and faster error correct is the key really. u cna only ake things spin so fast!