[gstreamer-bugs] [Bug 364856] New: videoscale + ffmpegcolorspace problem

[GStreamer (bugzilla.gnome.org)]

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  GStreamer | gst-plugins-base | Ver: 0.10.10

           Summary: videoscale + ffmpegcolorspace problem
           Product: GStreamer
           Version: 0.10.10
          Platform: Other
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-base
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: jderose at jasonderose.org
         QAContact: gstreamer-bugs at lists.sourceforge.net
     GNOME version: Unspecified
   GNOME milestone: Unspecified


I'm working on a DVD ripper and have encounter a strange problem.  I'm creating
thumbnails from each title, scaled to the correct aspect ratio taking into
account the pixel-aspect-ratio caps property.  At certain target resolutions,
the resulting frame is black and white and is sheered to the left (I have png's
below to illustrate).  At other resolutions, the color is correct, but the
sheer is steeper.  Seems to be a problem with the pixel array access math.

The pipeline is dvdreadsrc ! dvddemux ! mpeg2dec ! videoscale !
ffmpegcolorspace ! pngenc ! fakesink.

I'm picking up the frame in a 'preroll-handoff' handler.  The source video is
720x480 with a pixel-aspect-ratio of 32/27.  If scaled to:

853x480 (correct aspect ratio): black and white, sheered to left.
852x480: no error
851x480: correct color, but even steeper sheer to left


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