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Thread: ILDA Format BS

  1. #11
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    Quote Originally Posted by James Lehman View Post
    I think you understand that there is a wonderful disconnect between laser vector art and a common multi channel sound card.
    Way to completely miss the point, James. Again.

  2. #12
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    A whole lot of time and money has gone into the development of the now common and very inexpensive multi channel sound card. None of that was driven in any way by the needs of the laser display community. Yet, every bit of it is to our benefit.

    No telling what the future will hold, but for the past many years and for some time to come, multi channel sound cards can provide EXACTLY the right kind of signals for laser projection.

    Sound cards are still being developed and improved; more channels higher sample rates.

    The connection between sound cards and lasers is the wave file format. It's all there and it's all done; open and free.

    Anyone with an inclination can get involved and make a contribution.

    Consider the growing number of people who have no other way to do it.

    Writing about what might be is fine.

    Right now, I'm working on what is.

    James.
    Last edited by James Lehman; 01-11-2009 at 23:47.

  3. #13
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    A laser points a beam. To draw, you move that point to a location on a surface. You specify the location and the speed at which it moves there. This is easily done by a series of intermediate points. This should be old news but it obviously needs restating. When you store the process to file it doesn't matter how you derive your locations and speeds conceptually, and it doesn't matter how you're doing the vector drawing in hardware. Whatever you do you need to have a stream of data, or a set of instructions. The latter is pointless because then it really IS system dependent, as you have to build an interpreter and chew extra CPU time just to save a bit of storage space. With a stream of points at regular intervals, raw PCM wave data is as good a way as any, and given that much cheap audio hardware exists, this is likely the best way to go. Who cares if the file is nominally 30KHz or 300 KHz, it's down to the hardware to play it at the right speed. Even audio is good for 192 KHz now, how much more do we need? Once most people want the extra capability more than that could offer, they're usually buying more scanners instead of faster ones.

    For a non-M$ format to store the PCM data, I suggest looking at lossless compressors. Laser scan data likely compresses extremely well, with less CPU overhead than a dedicated vector interpreter. This way complex patterns can be rendered to PCM data and then played back on lesser machines. Ideal for shows, when you really don't want to risk theft or damage of your best computer.
    Last edited by The_Doctor; 01-12-2009 at 04:02.

  4. #14
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    Quote Originally Posted by The_Doctor View Post
    A laser points a beam. To draw, you move that point to a location on a surface. You specify the location and the speed at which it moves there. This is easily done by a series of intermediate points.
    I still don't think there's no room for advance here. Look at the successful standards in other fields that are related: PostScript uses a programmatic form for generating ink on paper. When you upgrade your printer, you can keep using the same old PostScript- it still works! In fact, I can take old PostScript from a my old LaserWriter driver and print it on the 2400dpi HP behemoth I have in the repro office. It comes out looking spot on, better than the LaserWriter ever could.

    ILDA, WAV, whatever you want to use, the point is that it takes considerable tweaking to make your output look as good as it possibly can. When you've done that tweaking, it won't look better than that, ever, anywhere. And as for tuning my scanners- what a waste of time! Why can't the scanners tune themselves? And as for the situation with laser power output- that's just ridiculous. We're firing lasers around with open-loop power control!

    What I want to see is a world where lasers and scanners know what they're doing. We have it now with almost every other field of computer control, up to and including car suspension systems. I think we're within a few months work of actually getting there, if we worked together and stopped bickering over which bad solution is best.

    What I'm saying is, this turd is polished enough. Let's build the next generation and stop wasting time improving something that was designed in the early 90s for machines three orders of magnitude less capable.

  5. #15
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    I don't agree. That logic is making several new systems that aren't any better than before. People use hugely expensive and powerful machines to run tasks that they used to run on far lesser machines. Good engineering comes from adapting to limits and overcoming obstacles. It does not come from filling available capacity. That's usually called bloat, for good reason.

    Put the emphasis on 'polish' rather than turd, and you get the idea. When a wheel is as simple and as round as it gets, the LAST thing to do is try to reinvent it just because it looks like it can't change for the better. You need to sort the system into manageable chunks. We're talkign about data storage here, and compatibilty with basic process. If you want closed loop power control, great, I'm all for it, but you still have to store the control signals.

    EDIT:
    What's important is not to try to replace one concept of storage with another. Graphics and audio programs have solved this long ago. Sometimes a vector form works, other times you want a proprietary form for the system that made it, for continued development. Other times you want a bitmap or WAV. Other times you want RAW data in byte streams. Yet other times you want to load one format and save another. All this they do. Laser programs need to emulate that instead of fighting over subsets.

    One of the ultimate storage systems is the original DX7 synthesiser data format for a sound. Take that famous sound used as the solo in the X-Files theme. I know where that sound comes from, it's storable in precisely 155 bytes! You can download it for free if you know where to look and what to look for. But context is everything. While this is storage that makes vector art look bloated, it's HIGHLY hardware dependent, and even then you have to add yet more hardware to recreate that sound as most of the world knows it. I am saying this to drive home the point that 'improvements' limit to very exact and demanding situations for rendering. The whole point of the ILDA files and anything else is to avoid that.
    Last edited by The_Doctor; 01-12-2009 at 04:32.

  6. #16
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    The Doctor....

    I think I love you.

    James.

  7. #17
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    *runs* Screaming.

    But I aims to please. More to the point, I go with my instincts, once logic and information have done what they can.

  8. #18
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    Quote Originally Posted by The_Doctor View Post
    *runs* Screaming.






    f*&king breeders!

    James.

    BTW, you know I love you too, heroic!
    Last edited by James Lehman; 01-12-2009 at 23:27.

  9. #19
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    Some assumptions here are that laser display will stay analog. As soon as a smart person creates a better galvo driver (perhaps one that offers feedback information to the host) with a bidirectional digital interface any argument of using WAV falls flat on the floor. However, the ILDA format would stay relevant because it is only a mechanism to define the points and not a way to send information to the galvos.

  10. #20
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    um.. whats all this about "points" instead of WAVE? ilda files store points SO DO JAMES"S WAVES.. you can never send "POINTS" to your scanner you send VOLTAGE.. no matter how you look at it, you are sending analog voltage..

    Some of you seem to think you can stuff an ilda file into your scanner amps and it will play it, not true, you have to send it thru the DRIVER for your DAC, which turns the INSTRUCTION (points) into ANALOG VOLTAGE ! !
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