[Bug 762736] New: compositor: revert 754465

[GStreamer (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=762736

            Bug ID: 762736
           Summary: compositor: revert  754465
    Classification: Platform
           Product: GStreamer
           Version: 1.7.2
                OS: All
            Status: NEW
          Severity: normal
          Priority: Normal
         Component: gst-plugins-bad
          Assignee: gstreamer-bugs at lists.freedesktop.org
          Reporter: philippe_renon at yahoo.fr
        QA Contact: gstreamer-bugs at lists.freedesktop.org
     GNOME version: ---

I am pretty sure that https://bugzilla.gnome.org/show_bug.cgi?id=754465 should
be reversed has it now addresses no issues and adds unnecessary complexity to
the compositor.

See https://bugzilla.gnome.org/show_bug.cgi?id=757610 for related discussions.

This pipeline was used for testing:

compositor name=mixer ! videoconvert ! autovideosink \
videotestsrc ! queue ! mixer. \
udpsrc port=9000 ! textrender ! videorate drop-only=true ! video/x-raw,
framerate=10/1 ! queue ! mixer.

Starting it and sending an udp packet to port 9000 will result in this error:

ERREUR¦: de l'element /GstPipeline:pipeline0/GstCompositor:mixer¦: At least one
of the input pads contains alpha, but downstream can't support alpha.
Information de d¦bogage suppl¦mentaire¦:
../../../../gst-plugins-bad-1.6.3/gst-libs/gst/video/gstvideoaggregator.c(587):
gst_videoaggregator_update_converters ():
/GstPipeline:pipeline0/GstCompositor:mixer:
Either convert your inputs to not contain alpha or add a videoconvert after the
aggregator

This error is expected and clear. Adding the converter as suggested works and
the pipeline will run fine with it.

Now, reverting the fix for 757610 (by simply forcing has_alpha to TRUE in
gst_videoaggregator_pad_sink_getcaps()) and re-running the above test will
yield the exact same result. The fact that downstream does not support alpha is
handled (in all cases) in gst_videoaggregator_update_converters(). This method
properly detects that downstream does not support alpha and provides an
explicit error message when needed.

This leads me to believe that the fix for 754465 is now obsolete and only adds
unneeded complexity to the compositor code.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.