[HH] Burn custom art on a DVD

[Jerry Feldman]

Thanks guys I'll report back to him.

On 05/12/2014 02:28 PM, Greg London wrote:
> I did asic design on CD and DVD burners for a number of years
> but it was years ago and before lightscribe was an option,
> so I can't really compare burning data to a disc to lightscribe.
>
> I don't know as much about the physical process
> but I don't know what is meant by "test grooves". My understanding
> is that burning a cd doesn't actually put grooves on it like
> a vinyl record but rather turns the transparent polycarbonate
> dark so that it does not reflect light from the aluminum disk
> underneath.
>
> So that would be the first issue/question, whether the physical
> process will actually do what they want to do.
>
> The second question is one of synchronization between the
> laser and the spinning disk. I worked on the CD read section
> of the chip, taking a stream of high speed data, de-interleaving
> it and running it through a 10b8 error recovery block, so
> I'm not as familiar with DVD's as CD's but I'm not sure that
> there is any sort of "index hole" marker on the CD to physically
> align the head back to the same spot.  audio CD's are one big,
> long spiral of data starting from the inside and working out.
> DVD tracks are concentric circles with sectors and whatnot.
> But  I don't know of there is any kind of index hole so that you
> could put down a stream of 1's on one track, move the head out,
> and then put another stream right alongside the previous stream.
>
> If the only requirement is to create a specific pattern
> on a single track, it should be possible. But if you
> want to lay down data on different tracks and have them
> be physically aligned with each other, I'm not sure
> that's even possible.
>
> The other bit of weirdness is that the RPM changes as you move
> the head to different tracks. The goal is to achieve constant
> linear speed over the track which gives you constant data
> rates coming off the head.
>
> Back in the day, audio CD drives were built with only very
> small data buffers in silicon, usually just enough to perform
> de-interleaving, 10b8 error correction on one block (48 bytes)
> while receiving the next block. So, as the head spiraled further
> out from the center, the disk would be spun at slower and slower
> rpm's.
>
> I think DVD's generally follow this Constant Linear Velocity
> approach, which means you've got more data in a track as you
> move further out from the center. This doesn't make it impossible
> but if you want a couple of "test grooves" to lay side by side
> then they'll default to being the same linear length, not the
> same arc of rotation.
>
> Lastly, based on how our chips worked, I can't even imagine
> getting direct control of the heads through software.
> Maybe other chips let you have more direct control, but
> there is so much data flying that most of it is automatic.
>
> By the time the serial data comes off the disc, its already
> run through serial de-interleaving, 10b8 error correction,
> and a bunch of other hardware blocks before the software
> ever sees it. prior to that point, its just moving too fast
> for software to keep up.
>
> I think the best you could hope for is to work within the
> existing DVD format and simply try to control what track
> the head is on and then give it a block of data to write.
>
> And even then I don't think there is any way to align one
> track to the track next to it.
>
> Anyway, this is all very fuzzy recollections of stuff
> I worked on a long, long time ago, in a galaxy far away.
>
> Someone more current might be able to do it no problem.
>
> Greg
>
>
>
>
>
>
>> My son-in-law got this from his boss. I assume he wants to burn art into a
>> lightscribe DVD. The place of business is in East Cambridge, his wife used
>> to live 2 doors away from me while she was married to someone else.
>>
>> -------
>> The objective is to burn many grooves on the DVD that will NOT be holding
>> any data or pictures.  Imagine that you have a pattern template that you
>> have drawn using some drawing tool and you want to burn  "grooves" on the
>> DVD using the DVD writing head.  There are "artist" specific software that
>> do this however, they are not precise enough for my friend's purposes
>> which is to create "test grooves" to test various organic compounds using
>> low voltage electricity.
>>
>> So I guess what I am looking for is someone that can write a firm ware to
>> move the head AND provide a "crude" user interface to draw simple straight
>> lines (for the template) and use the DVD writer to etch the grooves along
>> the lines created by the user.
>>
>> Here is the device:  HP CDDVDW TS-L633N 0300 195 (LightScribe)
>>
>> They will pay good money for an electrical engineer that can do that.
>>
>> I hope this is helpful.  This will not be used in any commercial capacity.
>>  It is only for testing in a laboratory environment.  Thanks.
>> -------
>>
>> --
>> Jerry Feldman <gaf at blu.org>
>> Boston Linux and Unix
>> PGP key id:3BC1EB90
>> PGP Key fingerprint: 49E2 C52A FC5A A31F 8D66  C0AF 7CEA 30FC 3BC1 EB90
>>
>>
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>

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
PGP key id:3BC1EB90 
PGP Key fingerprint: 49E2 C52A FC5A A31F 8D66  C0AF 7CEA 30FC 3BC1 EB90

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