[ANSWERED, Multiple Graphics Cards Not Supported] Spout error with multiple graphics cards


  • Hi,

    I am trying to use Spout (on a Windows10 PC) to sent a camera signal to Zoom. Everytime I activate Spout in my stage setup I get the error "Cannot create DirectX/OpenGL interop". I am trying lot's of stuff but couldn't yet find a solution.

    Any ideas what causes the problem?

    Thanks!

  • Tech Staff

    @rl

    What type of PC are you using? What video card does it have installed?


  • @dusx

    It's a desktop PC, Intel-i5.

    I am using 2 Graphiccards right now. One NVIDIA Quadro M2000 and one NVIDIA GTX 770. 

    I tried to setup GPU for on the M2000 for Isadora and for Zoom.

    Using the latest Spout release.

    One thing I couldn't try out yet: my Gui of Isadora as well as Zoom is on the monitor connected to the 770, while I am trying to render everything on the M2000. (There are 4 Monitors connected to the M2000 showing fullscreen stages of isadora). Could that be an issue?

    If I switch to CPU Sharing in Spout I don't get the error message, but the images coming out of Isadora via Spout in this case is just a lot of horizontal distorted lines.

  • Tech Staff

    @rl said:

    I am using 2 Graphiccards right now.

    This can cause lots of issues with more things than just spout. Isadora is not designed to be used with multiple graphics cards.

    From the "System Requirements For Isadora 3" Support Article:

    Isadora is not designed for use with external graphics cards (eGPUs) or machines that have multiple discrete GPUs. 

    Running Isadora on machines utilizing unsupported hardware configurations may have unexpected and undesirable results in terms of performance and usability.

    Unfortunately, it can be this way with many other pieces of video software too. Counter-intuitively (even for me), putting multiple graphics cards in the same machine doesn't immediately translate to a boost in power, it can actually bottleneck some things depending on what you're trying to do, and outright make other things impossible. My goblin brain wants more hardware to mean more bang, but it's often more complicated than that.

    This article is about pros and cons of using multiple GPUs in a gaming PC, which isn't precisely the right topic for this use-case, but communicates some of the pitfalls in general if one replaces references to "games" with "software":

    Another disadvantage is that not all [pieces of software] benefit from multiple graphics cards and some graphics engines do not handle two cards well. Some [software] may show a decrease in performance [with multiple GPUS] over a single graphics card setup. In some cases, stuttering makes the [video output] look choppy. [...] The performance benefits of a dual-card environment vary depending on the other components in the computer system. Even with two of the highest level graphics cards, a low-end processor can throttle the amount of data the system provides to the graphics cards.

  • Tech Staff

    @rl said:

    One thing I couldn't try out yet: my Gui of Isadora as well as Zoom is on the monitor connected to the 770, while I am trying to render everything on the M2000. (There are 4 Monitors connected to the M2000 showing fullscreen stages of isadora). Could that be an issue?

     Most likely it is an issue with passing the video texture between the video cards, so getting everything on one card is preferred and RECOMENDED!
    Now with that said, you might be able to use the 770 as an additional output/s card (maybe).. I have had success in this type of setup in the past BUT moving the video from the primary card to the secondary card for output will be a bottle neck and of course as @Woland has mentioned this configuration is not supported. If you can manage to get the number of outputs required from a single card it will better serve you. Using a Matrox Triple Head or similar will actually provide better performance than passing video to a secondary card (if you can make it work).


  • Alright, that's what I was afraid of. Would 2 similuar cards (2 M2000) do a better job?


  • Anyhow: you were right. I just put the gui monitor onto the M2000 and one projector on the 770 instead. Now Spout works.