VP8 rendering issue

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  • #19103
    ebrandsberg
    Participant

    I have a single user that is having problems when accessing a Linux virtual desktop, when the VP8 codec is used.  Vector graphic based applications appear to work fine, but if they open a canvas drawing application, it shows a black window where the canvas would be.  If they use floating windows instead of a desktop, the applications work however.  If I disable X11 drawing mode, then the entire desktop stops working.

    Any thoughts?  I am looking at trying to enable H.264, but this isn’t implemented in X11 mode, so may impact performance for everybody.

    #19123
    ebrandsberg
    Participant

    Update:  While this appears related to VP8, the issue is more subtle.  Another user that previously did not have an issue is now having an issue as well, without having updated any software on their machine.  It was working, they left a session, opened a new one, and now is having the same issue.  Attached is a screenshot showing one app rendering fine, but Chromium is not.

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    #19154
    graywolf
    Participant

    Hello.

    A problem with VP8 codec could explain why disabling X11 drawing mode makes the whole desktop stop working. Could you provide some more detail: you see only a black screen, connection failure or what?

    About H.264, it works in X11 mode as well as VP8. H.264 is the first choice, when available. Video encoding and X11 work together, an optimizing algorithm chooses the best mode in real time: the specific video codec in use doesn’t matter.

    #19171
    ebrandsberg
    Participant

    More information:  It appears that the problem can be resolved by having the options “fit to window” and not having the desktop in full screen mode.  I believe the issue is fundamentally something to do with the display drivers the systems are using, and how VP8 is interacting with them.  By resizing, my theory is that it is adjusting the render flow to avoid the issue.  I will update once I validate what display drivers the users with the issue are using, but this provides a reasonable workaround.

    #19184
    fra81
    Moderator

    Hi,

    can you confirm you’re really using VP8 and not H.264? Please note that H.264 would be used by default where available. You can find this information in the Display settings panel in the session menu. I suspect you might be using a hardware encoder and there is some problem with video drivers.

    Session logs could be useful to sort this out. See https://www.nomachine.com/AR10K00697 and https://www.nomachine.com/DT10O00163#2 for server and client side logs, respectively.

    #19185
    ebrandsberg
    Participant

    Per this feature request, H.264 is not supported in X11 mode, so this shouldn’t be the issue, correct?

    https://www.nomachine.com/FR11O03550.

    If this FR has simply not been updated, and H.264 is in fact available in X11 mode, you may be correct.   In testing, I was not able to get H.264 enabled on my system (by disabling X11), but I also never saw the problem.  It is possible it is kicking in for the people having an issue.

    I am also unclear on the h.264–I do not have a license for it, I only have the standard 4 seat workstation license.  Is H.264 enabled by default now even without the license?

    #19187
    fra81
    Moderator

    That FR only refers to H.264 hardware encoding on server side not yet available when using the X11 vector graphics mode. H.264 software encoding is always included in all licensed products (Workstation included), without any need for a specific license. As for the decoding side, software encoding is available in all licensed products and wherever hardware decoding is supported (that practically includes all Windows and Mac clients). If you are connecting from Windows, H.264 should be available.

    At this point, I would try to disable hardware decoding on the affected client (https://www.nomachine.com/DT10O00157#5.7.).

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