Gibberish video on x86/AMD-based HTCP when playing WMV3/VC1 videos

  • The following comments are all relating to LibreELEC (official) 7.0.2...

    I've been changing around a LOT of my home entertainment hardware lately, and as part of all this, I decided that it was about time for me to "upgrade" from the trusty old OpenELEC 5.0.8 that I've been using for a long time now on my AMD E-450 based HTPC to the latest and greatest official LibreELEC release.

    Well, I tried that, and mostly everything still worked (which is the good news) but I encounted two regressions that are serious enough to force me back to OpenELEC, at least for the time being. These are as follows:

    1) Apparently, LibreELEC 7.0.2 tries to use ff-wmv3-vdpau (HW accel) to render any and all WMV3/VC1 videos on this hardware, and I'm sorry to report that, for me at least, this seems to fail 100% of the time. LibreELEC obviously believes that it is playing these videos just fine, but in fact, the screen just gets filled with pixelated gibberish, tending heavily towards the greens. I've checksed carefully, and this is only a problem strictly and only for WMV3/VC1 videos. WMV1 and WMV2 videos play just fine, as do all MPEG4 or MPEG2 videos. And to be clear, the problems arises when playing either WMV3/VC1 main profile vids or advanced profile ones.

    (This seems to me a glaringly serious and glaringly obvious bug, and I'm a more than a little preplexed that nobody else has already reported it. Has anybody else already reported this?)

    2) LibreELEC 7.0.2 seem to mostly properly support my Logitech M305 mouse... as did OpenELEC before it... but with LibreELEC 7.0.2 the left mouse button just doesn't seem to have any effect at all anymore, which is distinctly un-good.

    I hope and trust that the above two problems can be resolved in some future release, because I really do have the goal of switching over to LibreELEC as soon as I can do so without losing critical (to me) functionality.


    P.S. OpenELEC 5.0.8 only tried to use ff-wmv3-vdpau (HW accel) just for WMV3/VC1 advanced profile videos. It made no attempt to do HW accel for WMV3/VC1 main profile videos. I am pleased to see that the libreELEC team is apparently working to try to implment HW accel for all kinds of WMV3/VC1 videos, and will be even more pleased when that effort bears some usable fruit.

    Until then however, I wonder if there is a some way of simply tweeking LibreELEC to get it to simply never try to use ff-wmv3-vdpau. If there were a way to do that, then that might be an adequate work-around for me, until such time as LibreELEC's use of this decoder can be made to work reliably. (None of my vids are of sufficiently high bitrates so that they even need the HW accel, given the strength of the CPU I'm using.)


  • no more work is going into the 7.x line, I suggest you update to the alpha builds and report back

    Ok, I just now downloaded and installed and tried the 7.90.009 image for x86.

    The good news is that the left mouse button now works OK.

    The bad news is that playback of WMV3/VC1 video still comes out as utter gibberish on the screen. So, you know, that looks like a major problem there. (Again, this is on an AMD APU, and an attempt is being made, by LibreELEC, to use VDPAU for decoding these videos. I could just turn off the VDPAU HW acceletarion, but then if i do that, some of my higher bit rate MP4s won't play.)

    Anyway, by trying out this new test release, with the new skin, I've found an even worse problem.

    It appears to me that in this new skin, the ability to calibrate the size of the displayed image has been completely removed. I found a "calibration" section in one of the menus, but it only allowed for selection of either 2 or 3 video buffers. Gone is the ability to adjust Kodi to compensate for overscan. This is an enormous problem for me, because I have a particularly brain-dead Panasonic 50 inch plasma that insists on doing 2.5% overscan and I can assure you that there is no way to turn that off, period. (I looked into this ad infinitum, and this was just some Panasonic engineer's stupid idea for a way to save money and make the lower priced models in this line of TVs less capable. The higher models of this same TV do have firmware and menu adjustements that allow the overscan to be disabled, but not this specific model.)

    So anyway, unless somebody puts back the old Kodi capability to actually calibrate the displayed image, you know, in order to adjust for (stupid) display overscan, I guess that I'm going to be stuck on using only pre-17 Kodi versions forever... or at least until I buy a new TV, probably sometime in 2023.
    [hr]
    Oh! And by the way, a 2.5% overscan (on each side of the image) may not sound like a lot, but I can assure you that it is enough to make the various skin menus mostly or entirely unusable.

    Edited once, last by ronbaby (December 13, 2016 at 9:12 PM).

  • Hey, sincerly, thanks a lot for the tips! I had the menu mode set to "Advanced" but obviously, "Expert" was what I really needed. So now I have the overscan calibration problem sorted out, and thanks to the clues you threw me I've also managed to selectively disable VDPAU for WMV3/VC1, so that's all good now too. (Well, anyway, my vids are playing OK. But I hope and trust that you guys will keep it in the backs of your minds, for the future, you know, that VDPAU HD accel for WMV3/VC1 just plain isn't working, at least on AMD GPU hardware.)

    Anyway, I'm a happy camper now. One of the main menu screens for one of my ripped DVD ISOs came up as just an all black screen, but other than that one very minor thing, everything else is working beautifully now.

  • The WMV3 issue looks like a driver problem. When it is fixed upstream it will be part the next releases.

    A search on freedesktop.org shows two bug reports this year: 96600 – [RV630]: a lot of artifacts appears on a screen playing some videos through VDPAU with hardware acceleration and 94381 – VC-1 VDPAU decoding on radeon causes occasional garbage.

    However the three samples from the bug reports play well HW accelerated on my AMD C-60 netbook with 7.90.009.