Performance Issues using Envelope Generators

  • Hi there

    i use an iMac 2.66 GHz Intel Core i5 with 8 GB RAM and running OSX10.7.4\. In theory, it's a more 'powerful' machine than the Isadora recommended system requirements.
    I've had this same problem before when i was working on another project -- when i use Envelope Generators to manipulate the values of still images (jpgs, tiffs, or pngs..) the result is always rather 'jittery'. all i'm doing is using an Envelope Generator to have the horizontal position values of a picture go from a negative value to a positive value (essentially, i want the image to move from left to right on the screen over a period of time....)
    as it's moving across the screen, the image jitters and jumps and shakes -- it looks like video that's 'lagging' or something. it's super problematic and i'm at a loss of how to fix it. i thought last year that it was my computer acting up, but i have since had it rebooted etc and the operating system re-installed. 
    any ideas on what's causing this and how to fix it? 
    the show i'm working on is almost entirely manipulating still images to pan, zoom, spin, etc and it has to look smooth! help!
    thank you
  • Izzy Guru

    What is the size of the image, are you using Isadora Core or the standard version? What is the speed rather fast or slow?


  • What do you mean by ”manipulate the values of still images”. Is that you using picture player and projector and changing pos, spin, zoom etc values in projector. I tried with envelope++ with neg values and it works smooth as silk.

    8000x8000 JPG 16mb very detailed NASA pix of earth

  • The transforms you are doing are executed on the CPU, so for large images one  quickly (much quicker than in the case of the GPU execution)  hits the "jitter" problem. You could try to achieve the same effect with core actors. I, on the other hand, had to write a standalone application to move an 3000 pixel wide image across the screen without jitter -- it was done on GPU, and produced the fluidity, which was impossible to achieve in Isadora. I am talking about interactive speeds.

  • Thanks for your comments.

    Michel, I am using Isadora Core and i've tried reducing the size of the image even to the point of it looking very pixelated. the speed i tried was pretty slow -- 20 seconds for a small image of a cloud to travel from left to right....
    vanakaru, yes, that's what i mean by manipulating the images. and the image you used is much larger than anything i've tried. can you think of why it's not as smooth as silk for ME?!
    eight, is that fluidity really impossible to achieve in Isadora? 
    still not sure how to fix the problem. further advice appreciated!

  • Hi Would you put a screenshot of your patch that we see witch actors you use to manipulate the images Best Mehdi

  • Hi Mehdi

    i've tried it these two ways....

    ba58e3-screen-shot-2012-09-09-at-7.09.22-pm-2.png bc2128-screen-shot-2012-09-09-at-7.14.04-pm-2.png

  • I tried once again with few different pictures. It works just like before - great. And my mac is not as fast as yours.

    How do you connect to the projector(actually I tried on external monitor, projectors settings play a role sometimes as well). 
    Could you check what the Console is telling you when the video stutters.
    BTW I get on Status Window Cycl:256 VPO:0.0 FPS:30\. How about you?
    And lets check what you have on Isadora Preferences?

  • vanakaru, thanks so much for all that.

    i've tried an external monitor, but it also does it on the small stage preview screen (when i click force stage preview) 
    last project when i had the same problem, it did it whether it was through the projector, on the external monitor, or in the small stage preview on the iMac monitor. it always stutters in the exact same places...
    my status window VPO: 0.0 and FPS: 30, but the Cycles fluctuate a lot between near 230 and 270....however after trying several times, i can't notice a pattern in whether they drop or skyrocket at the places where it jitters -- it's just constantly changing.
    could that have something to do with it?
    i've attached screen shots of my preferences....please let me know if you notice anything relevant!

    8a9b70-isadora-preferences-1.png 6e865a-isadora-preferences-2.png 698ff4-isadora-preferences-3.png c673dc-isadora-preferences-4.png 2ab46f-isadora-preferences-5.png

  • I thought you may have Threaded Movie playback checked. Uncheck this and see if you get better results. If I remember right Picture player specially does not like it.

  • tried.

    unfortunately, still jumpy...

  • I really is puzzling. I have the same settings, same preferences and lesser mac?

    Try this. You do not need to log in to download the zip(16.07mb). I put the Isadora patch and a picture file I was testing with in it.

  • if you change all the rate times to 10 seconds is it still as smooth?

  • Yes. Run it 20 sec if you like.

  • mine's jumpy when i do 20 secs

  • The one thing I noticed when I tried to record a screen for you with iShowU HD. It started stutter just a bit because this app takes lotsa CPU. So I wonder if you have something running in background that competes with Isadora.

    I am on 10.6.8\. i wonder if this makes difference. I have Lion installed on external drive(never got to use it) that I may give a try.
  • Izzy Guru

    My Mac which is super old couldn't handle that patch you created @vanakru but I expected it with a 8000x8000 pixel image.

    What are you playing the file off? An external HD if so is it USB/Firewire, etc?

  • I don't know if my mac classifies as super old as well, but I have just tried to play the same JPG off my main drive SSD and off 1tb HDD in optibay(PATA!!!). No difference, runs great.

  • Tech Staff

    I just tested the patch on my windows machine with a 1920x1920 image.
    I tried a few different settings configs and can't get it to play smooth.
    It is inconsistent as to when and how the stutters occur, but they are there.

    running f24.