[Gstreamer-bugs] [Bug 98263] New - XV patch for GStreamer

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http://bugzilla.gnome.org/show_bug.cgi?id=98263

Changed by uraeus at linuxrising.org.

--- shadow/98263	Mon Nov 11 17:06:42 2002
+++ shadow/98263.tmp.28126	Mon Nov 11 17:06:42 2002
@@ -0,0 +1,57 @@
+Bug#: 98263
+Product: GStreamer
+Version: cvs
+OS: Linux
+OS Details: 
+Status: NEW   
+Resolution: 
+Severity: normal
+Priority: Normal
+Component: gst-plugins
+AssignedTo: gstreamer-maint at bugzilla.gnome.org                            
+ReportedBy: Uraeus at linuxrising.org               
+QAContact: gstreamer-maint at bugzilla.gnome.org
+TargetMilestone: 0.4.0
+URL: 
+Summary: XV patch for GStreamer
+
+Patch from Ben Liblit <liblit at eecs.berkeley.edu> (adding it here so I will
+not forget to get it merged)
+
+My video card (a GeForce 3) offers several settable XVideo attributes, 
+such as brightness, contrast, etc.  Two of those attributes are 
+XV_COLORKEY and XV_AUTOPAINT_COLORKEY.  I don't *completely* understand 
+these, but the impression that I get is that XV_COLORKEY is a pixel 
+which will be used as a video output mask: video is only painted over 
+those parts of the window which are colored using the XV_COLORKEY pixel.
+
+In the common case where you don't want any masking at all, you can fill 
+the entire window using XV_COLORKEY.  A simpler approach, though, is to 
+set the boolean XV_AUTOPAINT_COLORKEY attribute to "true".  This 
+apparently causes the driver to do the XV_COLORKEY window filling 
+automatically.
+
+Curiously, the Xine movie player turns XV_AUTOPAINT_COLORKEY off, and 
+leaves it off even after it is done.  So any subsequent video player 
+that comes along will not get any video in its video window unless it 
+either turns XV_AUTOPAINT_COLORKEY back on or else does some painting of 
+its own using the XV_COLORKEY pixel.  GStreamer suffers from exactly 
+this bug.  If Xine has *ever* been run on a display, then GStreamer's 
+xvideosink plugin will not yield any output.  :-(
+
+Attached below please find a small patch to fix this problem by turning 
+XV_AUTOPAINT_COLORKEY back on.  I've tested it on my system and it works 
+like a charm.  It should harmlessly do nothing on video cards that don't 
+have this attribute at all.  The patch fixes both videosink and 
+xvideosink.  I fixed the former before learning that it has been 
+deprecated by the later.  Feel free to ignore the videosink change if 
+that code is truly dead.
+
+MPlayer had this same bug until very recently; I discovered the problem 
+and submitted essentially the same fix, which was incorporated into the 
+recent mplayer 0.90-pre9 release.  If you're interested, see 
+<http://mplayerhq.hu/pipermail/mplayer-users/2002-October/022024.html> 
+and 
+<http://mplayerhq.hu/pipermail/mplayer-dev-eng/2002-October/012071.html> 
+for archives of the discussions which led to my current understanding of 
+the issue.