DVD Burners

[cman]

Can a particular DVD burner produce a different result when burning a DVD movie? I've burned DVDs on my desktop computer using the same DVD authoring software , same encoding software and the same Operating System and blank DVD media as I use on my laptop computer to find that the DVDs I produce on my laptop computer only work with certain DVD players while those burned on my desktop unit work on all my DVD players. I've used the exact same settings on all the software used. Is this caused by the hardware used to produce the DVDs? I can't seem to figure this problem out  ( different DVD burn standards between different manufacturers ? ). Anyone know anything about this? Thanks for any information....

[CommonTater]

Can a particular DVD burner produce a different result when burning a DVD movie? I've burned DVDs on my desktop computer using the same DVD authoring software , same encoding software and the same Operating System and blank DVD media as I use on my laptop computer to find that the DVDs I produce on my laptop computer only work with certain DVD players while those burned on my desktop unit work on all my DVD players. I've used the exact same settings on all the software used. Is this caused by the hardware used to produce the DVDs? I can't seem to figure this problem out  ( different DVD burn standards between different manufacturers ? ). Anyone know anything about this? Thanks for any information....

It has to do with "head alignment" ... the read write head in the burner is positioned by a mechancal servo that moves it in and out along the radius of the disk.  If it is not lined up to exactly the same spot as every other DVD player, it's going to produce disks that don't exchange well with different players but work perfectly fine in the drive that made them.  This is actually a common problem, especially with the less rigid construction of laptop drives.

[dedndave]

you might look at the writing speed
i have had occasions where, if i burn a CD with the higher writing speed, some drives may not read it well
slow it down to 32x or something - that seems to work on all my drives
notice that i am refering to CD's - but, it is probably similar for DVD's

[anta40]

It has to do with "head alignment" ... the read write head in the burner is positioned by a mechancal servo that moves it in and out along the radius of the disk.  If it is not lined up to exactly the same spot as every other DVD player, it's going to produce disks that don't exchange well with different players but work perfectly fine in the drive that made them.  This is actually a common problem, especially with the less rigid construction of laptop drives.

Interesting. Maybe you don't mind explaining a bit more?
This happened to me several times (CD though, not DVD). I burned several CD audios. Worked well on my laptop and on my tape, but not on my car audio player.

[sinsi]

I doubt it is a head alignment problem, it's not a floppy (stepper), more like a hard drive (servo).
More likely to be a power issue, if the diode isn't putting out enough power the pits aren't 'deep' enough.
A slower burning speed can help, the power has more nanoseconds to make an impression.

[Magnum]

I remember reading that DVD players in computers were supposed to be able to play more
DVDs without problems than players for home use.

I found that to be the case with music CDs that I have recorded on a computer.

Andy

[MichaelW]

It has to do with "head alignment" ... the read write head in the burner is positioned by a mechancal servo that moves it in and out along the radius of the disk.  If it is not lined up to exactly the same spot as every other DVD player, it's going to produce disks that don't exchange well with different players but work perfectly fine in the drive that made them.  This is actually a common problem, especially with the less rigid construction of laptop drives.

The original Philips CD design used three servo systems, one each for focus, tracking, and CLV. The tracking servo detected deviations of the focal point from the signal track and corrected the tracking as necessary, effectively forcing the tracking to conform to the disk. The focus servo performed a similar function (but to a higher precision) to compensate for vertical motion irregularities.

[FORTRANS]

Hi,

   I would agree with sinsi.  I could write CD's at the slowest
speed and not at higher speeds.  Whether power (gets my
vote) or alignment was to blame.

Steve N.

[CommonTater]

It has to do with "head alignment" ... the read write head in the burner is positioned by a mechancal servo that moves it in and out along the radius of the disk.  If it is not lined up to exactly the same spot as every other DVD player, it's going to produce disks that don't exchange well with different players but work perfectly fine in the drive that made them.  This is actually a common problem, especially with the less rigid construction of laptop drives.

Interesting. Maybe you don't mind explaining a bit more?
This happened to me several times (CD though, not DVD). I burned several CD audios. Worked well on my laptop and on my tape, but not on my car audio player.

Here ya go ...  http://en.wikipedia.org/wiki/Compact_Disc

[CommonTater]

I doubt it is a head alignment problem, it's not a floppy (stepper), more like a hard drive (servo).
More likely to be a power issue, if the diode isn't putting out enough power the pits aren't 'deep' enough.
A slower burning speed can help, the power has more nanoseconds to make an impression.

If the disk was being under-burnt, it wouldn't work *anywhere*.

The problem is that head positioning servo can only compensate +- 1/2 track width... if the heads are not matched within that distance it can lose the track center and will stop reading.

[MichaelW]

The problem is that head positioning servo can only compensate +- 1/2 track width... if the heads are not matched within that distance it can lose the track center and will stop reading.

What does "not matched" mean? For the servo to lose the track center the track would have to deviate by more then the sensing tolerance over a span of a few "pits". The servo system has to be able to compensate for large irregularities, in no small part due to an unstable disk material with a high coefficient of thermal expansion.

[hutch--]

I think they have improved in both write and read over time. I had a heap of DVDs that I recorded years ago that I thought had failed as they would not play on the earlier readers I had yet some years down the track using both a Lighton and a Samsung I can play all of them. It makes sense on a dodgy writer to use a slower write speed, I have seen that solve a problem in the past when a DVD written at full speed would not play.

I am fascinated at the cost of the newer ones, the Pioneer writers I used to use cost about $120 AU, now you can buy better ones for under $40 AU, some cheaper again. When they stop they do it without warning, I recently lost a LightOn writer that was not all that old, just chucked it out and replaced it with a new Samsung.

A CD is generally more reliable, I have some that I wrote as backups back in 1998 that still read perfectly. They were on Kodak blanks that cost $5.00 each so you were really pissed off if a write error occurred and ruined the blank disk. 

[cman]

Thanks for your responses! The strange thing is this only seems to occur with DVD-R discs. When I use DVD-RW discs I can play them in all my DVD players. Are DVD-RW discs more forgiving of write discrepancies between burners? I'm thinking about just getting an external DVD burner for my laptop , this might be an easy solution to the problem. 

[CommonTater]

The problem is that head positioning servo can only compensate +- 1/2 track width... if the heads are not matched within that distance it can lose the track center and will stop reading.

What does "not matched" mean?

It means that if you tell 2 drives "track 56" ... both heads do not move to the same place on the disc. 

[MichaelW]

It means that if you tell 2 drives "track 56" ... both heads do not move to the same place on the disc.

So you're assuming that the "track" positioning mechanism operates open loop? I can't see how such a system could be made to work at all given a disk material with a high coefficient of thermal expansion and a low modulus of elasticity, and the resulting uncertainty in disk-relative positioning. Using the dimensions from the original design, assuming a polycarbonate disk with a coefficient of thermal expansion of 67E-6/K, a length of 88mm (equal to the mean radius of the signal area), and a deltaT of just 20C, I get a change in length of ~~70 track pitches. And this is neglecting the effect of centrifugal force. I didn't bother to do the calculations, but the force will be substantial and acting on a low-modulus material it will produce a significant elongation.

Also, in the original design there was only one "spiral" track, and I don't recall seeing where this changed for the later designs.