The VideoLAN Forums

Hello.

I notice a graphic bug when I open a video file. It happens with the Video window borders..
Here is a screenshot :

http://img707.imageshack.us/img707/7583 ... tre1gl.png

Here is the skin (still in progress) : viewtopic.php?f=15&t=15831&p=228851#p228851

I experienced this very problem on Linux with some ffmpeg svn version a while ago. It seems the libswscale library that scales bitmaps to fit a given window frame fails to do the job. If so, 'vlc --verbose 2' should be helpful

But, whether on Linux (latest git for vlc and svn for ffmpeg) or on Windows (official vlc1.0.3), this problem doesn't show up any more.

Please, can you describe your config (OS, version, ..) and check logs with verbosity = 2 ?

Erwan10

My computer :
AMD Phenom II x4 965 (3.40 Ghz)
6 Gb of DDR3
ATI Radeon 4890 1 Gb
Windows 7 64 bits
VLC 1.0.3 (official)
and it happens too with VLC-1.0.4-rc-20091206-0202

Here is the log (verbose = 2) :

Thanks for your inputs.

I'm afraid you just discovered a bug related to your Windows7 being a 64 bit OS.

The problem is the following :

skins2 error: AlphaBlend() failed
skins2 error: AlphaBlend() failed
skins2 error: AlphaBlend() failed

in the source code, a 'msimg32.dll' dll is explicitly loaded. chances are this code is not portable in 64 bits.
More generally, skins2 refers to several 32 bit dll (msimg32.dll, user32.dll).

We need to find a 64 bit expert ..... Maybe, jb ?

Erwan10

That shouldn't be a problem since we don't see
msg_Dbg( getIntf(), "couldn't find AlphaBlend()" );
nor
msg_Dbg( getIntf(), "couldn't find TransparentBlt(), falling back to BitBlt()" );

That is weird indeed.

Actually, AlphaBlend is found, but a call to this function returns false.
MSDN (http://msdn.microsoft.com/fr-fr/library ... 85%29.aspx) only states an invalid parameter as a possible problem.

The same code (same skins, same vlc version) on WinXP works fine.
Maybe, it is not 64 bits but just Windows7 being more stringent on some parameters.
It could be interesting to give a try on Vista or Windows7 32 bits to see if the problem exists.

Erwan10.

I could reproduce that bug on Windows 7 32-bit, using the Navaga WIP skin.

But interestingly once I hid the video window and made it appear again, without pausing the playback, the window appeared normal again.

Config:

Dell Latitude 2100
CPU: Intel Atom N270 1.66 GHz
RAM: 1 GB
GPU: Intel 945 Express
GPU-RAM: 251 MB
DirectX 9.0+

Thanks aLtgLasS , that's interesting.

I've got some more questions if somebody can test them (I've got no Windows7 at hand)

- Is it only the video window that shows the problem ? What about the playlist windows ?
- Does other skins also show this problem or just Navaga ?
- is it only those bitmaps that need to be scaled (as part of a resize process) that show the problem ?

fyi, Navaga uses the animated bitmap feature a lot, and hence AlphaBlend keeps on being called. And it seems to fail __only__ on some bitmaps that need to be scaled ...

Erwan10

It's just the video window with that problem. It are just the images that are resized. It occurs only after the video window has automatically been resized to fit the video. Immediately after you resize the window yourself the bug goes away. Also if you hide/show the window the bug goes away. So a simple redraw of the window after auto resizing might do the job.

EDIT: It is NOT only the resizable images that are affected, I just had it that also the video was affected and also static images in the upper and lower right corners. Part of the video and the window were totally gone, not just stripes.

The bug does not occur when switching from one video to another and the window is auto resized. Then the window stays intact.

I could not reproduce that behaviour in the default skin.

Weird, indeed. And not easy to figure out, as neither WinXP or wine(Linux) have this problem.

@xanax : do you still have the navaga skins you sent me (the one with the nbFrames syntax error). I am curious to know if this skins (where animated bitmaps were in fact disabled) also shows the problem.

By design, the inner part of the video is managed by one thread (vout thread) and the other windows are managed by a second thread (skins thread). I fear there might be a race condition at the OS level(a Windows7 bug ?). When animated bitmaps are used, the skins thread keeps on calling AlphaBlend. And the vout thread tries to reparent the video window on top of an area managed by the skins thread. ...

Also, maybe a test on Vista could be interesting to know if this problem is only related to the new Windows7 or older

Erwan10

Here is the latest version of the skin :
viewtopic.php?f=15&t=15831&p=228851#p228851

Hi,

Found in skins something that might cause the bug described in this thread. A patch has been committed today in vlc1.1. Feedbacks welcome with a nightly build that should be available as soon as tomorrow (vlc1.1 only)

Regards
Erwan10

While i´m currently in skin developing state too, i can confirm both errors (Alpha on Win7 x64 and the scaling issue). Especially the scaling issue isn´t restricted to unix, i get the same "rescaling" issues on my Win7 x64. This issue is gone, if you hover over a button element. Scaling issue appears most time on down(re)scaling a skin (e.g: if you openend a dvd and use the fullscreen while switiching back).

It seems this bug is gone in recent nightly builds.