GNOME Bugzilla – Bug 632333
Instead of Preview, Cheese displays a black screen because video format is incorrect
Last modified: 2011-01-17 20:25:53 UTC
Created attachment 172529 [details] Screenshot of Cheese with black screen I have built Cheese from source from the git master version. When I run it, I see a black screen instead of the preview, as can be seen in the image. I'm using clutter-gst-1.0 and this error happens both when I use libclutter-gtk-0.10-dev 0.10.4-1 from Debian and with git version of clutter-gtk.
Created attachment 172530 [details] [review] camera: Add capsfilter before video sink, to filter right video csp The video sink doesn't show the video with the default format, so this capsfilter filters the right format so the sink can display it.
I could be wrong but it seems that your patch is working around a clutter-gst bug. You shouldn't have to force any video format, the sink should negotiate the correct pixel format with our pipeline basing on the formats it supports. If I recall correctly the black screen issue was solved with clutter-gst 1.3 or clutter-gst from git. Could you please test it?
actually the bug causing the black screen was caused by this commit: http://git.gnome.org/browse/cheese/commit/?id=c6470f155e922318e1b41eba696cf1175c1705ff luciana, could you try to revert that commit locally and see if it does make any difference?
Daniel that commit is the only way clutter gtk initialization can be done. The other way was broken and worked by some odd chance (ebassi said this). IIRC the black screen was caused by a clutter-gtk bug that has been fixed in 0.10.6 or something like that.
Well, I did think it was strange that the video sink was not negotiating the format. I saw that they do this workaround in a test in clutter-gst-1.0, so I thought this could work for Cheese, but it is better if the video sink negotiates correctly. I had installed clutter-gst in jhbuild thinking it would get the git version. Now that I really have git version, it does fix the black screen problem. Instead of a black screen I see a pinky preview. When I click on effects, the effects that were shown before are still the same, but the others are also pink. Does anyone see that too? I had tried reverting the commit Daniel mentioned too, but it didn't fix the problem. Thanks for the tips.
any news for this report?
Upgrading Cheese and clutter-gst again from git I no longer see some effects pink, but the preview is now a black screen again. When I apply some of the effects it changes to a red screen.
It turns out after clutter-gst upgrade the only problem I had was that contrast and saturation were set to zero, so I couldn't see anything.