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Thread: LSX and RIYA Multibus Lite output lag?

  1. #1
    Join Date
    Apr 2010
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    39

    Default LSX and RIYA Multibus Lite output lag?

    Hey guys, long time no see! I fell out of the laser hobby for a long while, but I still kept a good bit of stuff around to tinker with!

    5 years or so ago, I bought LSX basic and a RIYA Lite DAC from DrLava IIRC. I grabbed a super cheap set of "15kpps" galvos, too. Never got very far with it, fudged a lot of cheap green pointer modules trying to make them modulate, blew up a flex drive or two, then gave up. I recently discovered the uber-cheap e-bay RGB modules, so I picked up the cheapest TTL one I could find. I figured I'd play around with this, then maybe start upgrading things as I go. There are so, so many new to me diodes to play with. I'm especially stoked over the easy and cheap analog greens... Anyway, what I've got works rather well for what it is. I've limited the scan angle to around half using the RIYA settings program, then I can scale down in LSX and actually manage sharp corners at 18k or so! I have no idea what my actual scan angle is, but ILDA pattern is less than a foot wide at 6 feet or so, so it's not much at all.

    All this is fine and good, but I'm having a strange output lag problem. The show will uh, show, fine in the preview window but the output will hang on a frame, then skip a few to catch back up. It's not a slightly discernible thing, there's times where it's gotta be playing less than a frame per second. The PC I am using should be up to the task (4770, 8GB, R9 290x) but it does seem to be CPU dependent. I can run youtube and realtime together and pretty reliably get the lag issue, but other times it will power through it just fine with no lag. I'm not trying to display too many points, either. One show that will lag pretty reliably is the wave expression demo show (test_live_audio_scope.rtd) Turning OpenGL rendering off seems to help a little, but the lag will still be there. I'm using a USB2.0 port directly on the motherboard, and while I can't disconnect all USB stuff I've pulled everything but the keyboard and mouse with no improvement.

    My RIYA is old enough that it has the USB plug problem, but I don't think it's a physical connection issue. Sometimes I have to plug the thing in once or twice to get it recognized, but wiggling the USB connector once the connection is open/show playing does not seem to cause the lag directly. I just found out about the connector issue searching up a fix for this problem. Besides a non-lite ethernet multibus dac, I haven't been able to find anyone else with this issue besides a German forum mentioning "i" series processors missing some old processor commands or something along those lines. I'm not too sure that sounds right, pretty sure i series was a thing when LSX released?
    https://translate.google.com/translate?hl=en&sl=de&u=http://laserfreak.net/forum/viewtopic.php%3Ff%3D18%26t%3D51418%26p%3D237711%26 sid%3D7caf8f00cd66a3a7e82fd5e9b8f0cd4c&prev=search


    I don't have any other non i7 computers to test, and if I did I'm not sure my license from this PC would transfer anyway. The RIYA is supposed to be a dongle, but Drlava needed what looked like a hardware id generated number for my specific computer. Should I e-mail DrLava for any new updates? I think my version is current up through 2014 or so.

    I guess my question is, is this a hardware limit of my cheap DAC or am I experiencing some other issue? My understanding is it's capable of 50kpps, so I can't be trying to display things too complicated? I don't have many (any) ilda files to test other player software, and the RIYA test program only lets me draw a frame at a time, so it's no good for checking lag. I guess that's what I'll probably try next, that or exporting a show to ILDA. I can do that, right?

    Thanks guys!
    Last edited by pontiacg5; 10-31-2016 at 22:53. Reason: formatting lost!

  2. #2
    Join Date
    Aug 2009
    Location
    Norway
    Posts
    308

    Default

    It does sound like there is something wrong with the USB connection, either physically or that the USB controller isn't able to send the data quick enough. I had a similar problem once and it turned out to be caused by an unrelated process running in the background using a lot of CPU time, probably not leaving enough room for the USB to function optimally. I closed that and it worked fine. So maybe check in the task manager if that's by any chance your problem as well.

  3. #3
    Join Date
    Mar 2016
    Location
    Portland, OR
    Posts
    47

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    To comment on your question about LSX updates. I'm almost certain your software isn't the most current if it's from 2014. The last update link I got was dated March 20th 2016. I'm not sure if that is the most current release, but certainly more current than what you've got. If you want the most current update, I would email DrLava for the link.

  4. #4
    Join Date
    Apr 2010
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    39

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    I've tried closing a lot of open process, but it doesn't seem to help much. When I am running LSX and youtube/plugincontainer.exe I am under 10% CPU load. I meant to check each CPU, I guess 12% is probably maxing out a single core. Maybe that's it...

    I did have a fairly old version of LSX, I went to e-mail DrLava and found the FTP server link he provided a while back and it looks like he has kept it up to date for me. The look of the program changed a little bit, it's much darker grey now than before. At first I thought the lag problem was fixed, then I tried a lot of spec/wave expressions from CMB's tutorials and the lag came back! Once the lag starts, it will stay untill I restart LSX.

    https://www.youtube.com/watch?v=_nNq...ature=youtu.be

    This was done at what I think is 35 degree scan angle at 14kpps, the flicker is real!

    I am ordering a new USB cable for the RIYA, to see if it's a connection issue. And, as much as it sickens me to say it, I think I might have to give wickedlasers some money for a laserdock dongle. I leave for a few years and come back and WL isn't being generally stupid and unsafe and not shipping vaporware for months on end? Never thought that would happen.

    I think I'm up to date on all the new software out right now from reading the last few days, nobody else is doing auto music visualizations right?
    Last edited by pontiacg5; 11-02-2016 at 07:50.

  5. #5
    Join Date
    Aug 2009
    Location
    Norway
    Posts
    308

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    It's maybe a technical pain in the ass but what I would do in this situation is to manually inspect the USB packets to the DAC to see what the problem is. You can use a program called wireshark with usbpcap, that lets to sniff USB transfers going to and from a device. Most likely you'll find one of two things: Either the stream of transfers from LSX is not as it should be, for example there are pauses lasting longer than one frame (33ms at 30 FPS) without any USB activity. This would indicate that the problem is with the PC, for example like I described in my first post. Or you might find that LSX is polling the status of DAC like it should, but that the DAC is returning a NOT READY signal, or no response at all while the lagging is happening. This might mean there is a problem with the DAC itself. If the communication was perfect, you'd probably see three transfers every frame, one status request, one status OK response and one data transfer containing the frame.

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