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Bug 749634 - compositor: Strange behaviour mixing streams
compositor: Strange behaviour mixing streams
Product: GStreamer
Classification: Platform
Component: gst-plugins-bad
git master
Other Linux
: Normal normal
: 1.5.1
Assigned To: GStreamer Maintainers
GStreamer Maintainers
Depends on:
Reported: 2015-05-20 13:47 UTC by David Fernandez
Modified: 2015-05-20 15:16 UTC
See Also:
GNOME target: ---
GNOME version: ---

Previous image (60.55 KB, image/png)
2015-05-20 13:47 UTC, David Fernandez
After image (132.86 KB, image/png)
2015-05-20 13:48 UTC, David Fernandez

Description David Fernandez 2015-05-20 13:47:55 UTC
Created attachment 303666 [details]
Previous image


Since this patch the behaviour of compositor is strange.

I use this pipeline to test:

gst-launch-1.5 compositor name=mix ! videoconvert ! xvimagesink \
   videotestsrc pattern=8 ! video/x-raw,format=AYUV,framerate=5/1,width=320,height=180 ! videobox border-alpha=0 top=0 left=0 ! mix. \
   videotestsrc pattern=21 ! video/x-raw,format=AYUV,framerate=5/1,width=320,height=180 ! videobox border-alpha=0 top=0 left=-320 ! mix. \
   videotestsrc pattern=18 ! video/x-raw,format=AYUV,framerate=5/1,width=320,height=180 ! videobox border-alpha=0 top=-180 left=0 ! mix. \
   videotestsrc pattern=0 ! video/x-raw,format=AYUV,framerate=5/1,width=320,height=180 ! videobox border-alpha=0 top=-180 left=-320 ! mix.

The output of the pipeline before the patch (I understand that is the correct output) is shown in the attached picture (previous.png). And the output after the patch can be seen in the other picture (after.png). The second one has a different height and width, and the position of the third stream is wrong.

It is a bug or it is a expected behaviour?

Comment 1 David Fernandez 2015-05-20 13:48:23 UTC
Created attachment 303667 [details]
After image
Comment 2 Matthew Waters (ystreet00) 2015-05-20 15:06:16 UTC
Thanks for the test!

commit d1419afef1521777a227eb5c83d4be4ccc405ef2
Author: Matthew Waters <>
Date:   Thu May 21 00:56:01 2015 +1000

    compositor/glvideomixer: fix up par handling
    We were using the wrong formula
Comment 3 David Fernandez 2015-05-20 15:16:08 UTC
Thanks for the patch!