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Bug 679612 - [videoconvert] produces empty output when converting from GRAY8
[videoconvert] produces empty output when converting from GRAY8
Product: GStreamer
Classification: Platform
Component: gst-plugins-base
Other Linux
: Normal critical
: 0.11.x
Assigned To: GStreamer Maintainers
GStreamer Maintainers
Depends on:
Reported: 2012-07-09 07:18 UTC by tom.winkler
Modified: 2012-07-10 09:10 UTC
See Also:
GNOME target: ---
GNOME version: ---

Description tom.winkler 2012-07-09 07:18:49 UTC
The following pipeline produces a single-color green image output instead of the expected grayscale output:

gst-launch-1.0 videotestsrc ! videoconvert ! video/x-raw, format=GRAY8 ! videoconvert ! autovideosink

Investigation the problem a bit more revealed that videoconvert seems to have a but when convertion data from GRAY8. The following pipeline shows that the data is all zero:

gst-launch-1.0 videotestsrc ! video/x-raw, format=GRAY8, width=8, height=8 ! videoconvert ! video/x-raw, format=I420 ! fakesink num-buffers=3 dump=true

Result of pipeline execution is here:

Gstreamer is 0.11.92 (tarballs from website not git head).
Comment 1 Wim Taymans 2012-07-10 09:10:55 UTC
commit aa261162d20c71956dcec783e00c57b832fe9ce6
Author: Wim Taymans <>
Date:   Tue Jul 10 11:06:02 2012 +0200

    videoconvert: fix offset and scale for GRAY
    Fix the calculation of the offset and scale values for GRAY formats. We also
    need to set the offset and base of the chroma values to match what the unpack
    function creates.