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Bug 633147 - Simple reverse negotiation pipeline is broken.
Simple reverse negotiation pipeline is broken.
Product: GStreamer
Classification: Platform
Component: gstreamer (core)
git master
Other Linux
: Normal blocker
: 0.10.31
Assigned To: GStreamer Maintainers
GStreamer Maintainers
Depends on:
Reported: 2010-10-25 23:40 UTC by Jan Schmidt
Modified: 2010-10-29 12:54 UTC
See Also:
GNOME target: ---
GNOME version: ---

possible patch (4.50 KB, patch)
2010-10-27 15:27 UTC, Wim Taymans
committed Details | Review
videoscale: Add unit test for working reverse negotiation (8.86 KB, patch)
2010-10-28 16:43 UTC, Sebastian Dröge (slomo)
committed Details | Review

Description Jan Schmidt 2010-10-25 23:40:03 UTC
gst-launch videotestsrc ! videoscale ! ffmpegcolorspace ! ximagesink no longer reverse negotiates correctly. Enlarging the window displays the video at the original size, with black borders.

Reverting f8abf35000570a8afe64268b430e998e2d735e61 fixes it:

commit f8abf35000570a8afe64268b430e998e2d735e61
Author: Wim Taymans <>
Date:   Thu Aug 26 15:12:49 2010 +0200

    basetransform: recover from invalid downstream suggestions
    When we are handling a buffer and need to allocate an output buffer, handle the
    case when downstream suggests us a format that we can't convert the input buffer
    to. In that case, check if there is another format available downstream instead
    of failing.
    Fixes #621332 and see also #614296
Comment 1 Wim Taymans 2010-10-27 15:27:09 UTC
Created attachment 173333 [details] [review]
possible patch
Comment 2 Jan Schmidt 2010-10-27 16:51:22 UTC
The patch fixes it for me, and doesn't seem to break anything, so yay!
Comment 3 Sebastian Dröge (slomo) 2010-10-28 13:04:05 UTC
I'll try to write a testcase for this later
Comment 4 Tim-Philipp Müller 2010-10-28 13:31:07 UTC
Comment on attachment 173333 [details] [review]
possible patch

Test case would be nice indeed :)
Comment 5 Sebastian Dröge (slomo) 2010-10-28 16:43:03 UTC
Created attachment 173415 [details] [review]
videoscale: Add unit test for working reverse negotiation

See bug #633147.
Comment 6 Wim Taymans 2010-10-29 11:11:13 UTC
commit ce919c0573a492baeeb57fff414f7f0fa42dfd69
Author: Wim Taymans <>
Date:   Thu Oct 28 13:29:31 2010 +0100

    basetransform: fix reverse negotiation
    When the downstream element suggests a new format, pass the suggestion
    upstream if we can't convert to it.
    Fixes #633147
Comment 7 Tim-Philipp Müller 2010-10-29 11:21:29 UTC
Comment on attachment 173415 [details] [review]
videoscale: Add unit test for working reverse negotiation

Awesome, please push this as well.