Qt5.5: X11 video window broken, cropped

[denisq]

Since yesterday, both with official VideoLan? and Packman packages, VLC is not able to show the video in fullscreen mode anymore. It only shows a quarter of the video (see attachment)

Furthermore, it does not respond to the "f" shortcut and I lose the mouse cursor when I move it insight the video area.

I have tried some other video output plugins (e.g., openGL) but it does not fix that behavior. Xine works well, but I do not know how many (video) dependencies it has in common with VLC.

How can I run a better diagnostic? What information do you need? I am running openSUSE Tumbleweed with all packages updated yesterday.

[denisq]

Screenshot of fullscreen issue

[Rémi Denis-Courmont]

If it broke even distro packages, then it's most likely a bug in whatever ELSE you changed yesterday. Without further details, there is pretty much nothing we can do here anyhow.

[denisq]

Well, I do think it is videolan related because when I install the beta packages (vlc-beta-3.0.0-2015021301.14.i586.rpm) it works fine. And when I downgrade to stable again, the bug re-appears. The it seems pretty linked to vlc since the only packages that I install are the vlc ones:

Installing libvlccore8-3.0.0-2015021301.14.i586.rpm (installed size 1.16 MiB)
Installing libvlc5-3.0.0-2015021301.14.i586.rpm (installed size 150.1 KiB)
Installing vlc-beta-noX-3.0.0-2015021301.14.i586.rpm (installed size 37.58 MiB)
Installing vlc-beta-qt-3.0.0-2015021301.14.i586.rpm (installed size 2.84 MiB)
Installing vlc-beta-3.0.0-2015021301.14.i586.rpm (installed size 324.6 KiB)
Installing vlc-beta-aout-pulse-3.0.0-2015021301.14.i586.rpm (installed size 29.7 KiB)

[Jean-Baptiste Kempf]

The bug is: ​https://bugreports.qt.io/browse/QTBUG-48321

Broken by 37f326297d45564298a2c8cb1958a81b858de57c

71df75966db5f51c66bff1c436dd1cb5a895b51b is half-the-fix, but not more.

Moreover, with Q5.5, you are no longer able to simply "double click" to get the window to fullscreen, for example.

The commit at fault is 53d289ec4c0f512a3475da4bbf1f940cd6838ace ("xcb: Use XIGrabDevice instead of xcb_grab_pointer with XI 2.2"). A quick workaround is to set the env var QT_XCB_NO_XI2_MOUSE to 1 and all is back to normal...

Short story: don't use Qt5.5

[Rémi Denis-Courmont]

For the umpteenth time, DO NOT MIX MULTIPLE BUGS IN THE SAME REPORT!!!

[Rémi Denis-Courmont]

The problem is not specific to fullscreen mode. It's easily reproducible in windowed mode too (for me anyway).

In this instance:

xwininfo: Window id: 0x100000b "big_buck_bunny_480p_h264.mov - Lecteur multimédia VLC"

  Root window id: 0x29a (the root window) (has no name)
  Parent window id: 0x1e1c080 (has no name)
     4 children:
     0x1000013 "vlc": ("vlc" "vlc")  853x556+0+29  +244+182
        4 children:
        0x1000032 "vlc": ("vlc" "vlc")  853x58+0+498  +244+680
        0x1000030 "vlc": ("vlc" "vlc")  853x18+0+480  +244+662
        0x1000017 "vlc": ("vlc" "vlc")  853x480+0+0  +244+182
           4 children:
           0x10000b4 "vlc": ("vlc" "vlc")  1280x300+0+0  +244+182
              1 child:
              0x1000128 "vlc": ("vlc" "vlc")  853x480+0+0  +244+182
                 1 child:
                 0x1400000 (has no name): ()  853x480+0+0  +244+182
           0x10000ba "vlc": ("vlc" "vlc")  1280x300+0+0  +244+182
           0x10000bc "vlc": ("vlc" "vlc")  100x30+0+0  +244+182
           0x10000b8 "vlc": ("vlc" "vlc")  640x480+0+0  +244+182
        0x1000015 "vlc": ("vlc" "vlc")  853x33+0+0  +244+182
     0x1000011 "vlc": ("vlc" "vlc")  853x28+0+585  +244+738
        5 children:
        0x10000a7 "vlc": ("vlc" "vlc")  28x23+1078+3  +1322+741
        0x1000021 "vlc": ("vlc" "vlc")  85x23+748+3  +992+741
        0x100001f "vlc": ("vlc" "vlc")  51x23+691+3  +935+741
        0x100001d "vlc": ("vlc" "vlc")  683x23+2+3  +246+741
        0x100001b "vlc": ("vlc" "vlc")  13x13+840+15  +1084+753
     0x100000f "vlc": ("vlc" "vlc")  853x29+0+0  +244+153
     0x100000d "vlc": ("vlc" "vlc")  100x30+0+0  +244+153

• 0x1000017 is the central stacked widget (stackedWidgetC).
• 0x10000b4 is the video widget.
• The video widget horizontal layout is a client side object without server handle.
• 0x1000128 is the "stable" widget within the video widget.
• 0x1400000 is the video output window handle (using !XVideo here). Note the different X11 client ID, as the video output plugin has its own XCB connection.

(You can add some debug to check the winId() properties.)

At that point, the last requested resize was 853x480. For some reason, the video widget is not updated, even though both its parent and child are resized correctly. I can't think of anything, this looks like a Qt bug to me.

[Jean-Baptiste Kempf]

It seems also here that the visible part is actually the old size, before the video was launched.

[Rémi Denis-Courmont]

In X11, window are always cropped according to their parent window, so that's normal. What's not normal is that the size is not changed.

[Melis]

Replying to denisq:

Screenshot of fullscreen issue

attachment:vlcdd.png​ Replying to courmisch:

The problem is not specific to fullscreen mode. It's easily reproducible in windowed mode too (for me anyway).

That is also confusion in Attachment - maybe to reporter "fullscreen" is entire video area when max window?

[denisq]

A remarks/comments:

• the video size is indeed the initial window size (when I maximize, it's limited to that initial size, when I reduce the window size, it scales down the video and scales up again upon increasing the window size until the point of initial window size)
• the first screenshot is maximized window. I will now attach a fullscreen screenshot which is actually very weird (toolbars remain visible)
• this bug does not occur in VLC beta (3.x), although it uses the same shared Qt5.5. Furthermore, openSUSE has been shipping Qt5.5 which should be considered stable
• as for the following aggressive comment, I do try to describe best the different elements that broke together, as they might be interrelated. I do not submit several bugs in the same report, I am just trying to make a good diagnosis to determine the right root cause (bug) to report.

   For the umpteenth time, DO NOT MIX MULTIPLE BUGS IN THE SAME REPORT!!! 
  

[denisq]

Fullscreen snapshot

[Rémi Denis-Courmont]

Replying to denisq:

• this bug does not occur in VLC beta (3.x), although it uses the same shared Qt5.5.

Actually, the bug affects VLC HEAD/3.0 just as it does VLC 2.2.

Furthermore, openSUSE has been shipping Qt5.5 which should be considered stable

VLC 2.2.x should be considered stable too. Yet evidently, there is a bug in either Qt5.5 or VLC 2.2. This is utterly meaningless. And from what I have seen so far, the bug seems to be in Qt5.5.

[Rémi Denis-Courmont]

Replying to denisq:

• as for the following aggressive comment

It's not about you, the OP. It's about (not) bringing unrelated mouse events problems into this window size bug.

[Jean-Baptiste Kempf]

See #15574

[Rémi Denis-Courmont]

Also #15520

[akostadinov]

I see same issue with Fedora 24, VLC version 3.0.0-git Vetinari (2.2.0-git-8754-g1c89583) and QT 5.6.1. Any ideas? I downloaded qt source RPM and see the patched line in the sources. So perhaps problem resurfaced?

[Rémi Denis-Courmont]

Replying to akostadinov:

I see same issue with Fedora 24, VLC version 3.0.0-git Vetinari (2.2.0-git-8754-g1c89583) and QT 5.6.1. Any ideas? I downloaded qt source RPM and see the patched line in the sources. So perhaps problem resurfaced?

Only someone who can reproduce the problem with that software versions combination can answer that question...