[gstreamer-bugs] [Bug 639321] New: deinterlace: field{1, 3} scanline pointers seem to be off by one field line

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=639321
  GStreamer | gst-plugins-good | git

           Summary: deinterlace: field{1,3} scanline pointers seem to be
                    off by one field line
    Classification: Desktop
           Product: GStreamer
           Version: git
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-good
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: robert.swain at gmail.com
         QAContact: gstreamer-bugs at lists.sourceforge.net
      GNOME target: ---
     GNOME version: ---


While working on some interlacing stuff I noticed something that looked strange
in deinterlace. In one particular case (field 0 is a top field), the field 1
and field 3 scanline pointers are one field_stride down from where they should
be. See the following patch.

I think the improvement given by the patch can be seen using either linearblend
or vfir (or weave, which is where I initially noticed it) when using one of
Monty's dv samples [1].

Check the output of:

gst-launch-0.10 uridecodebin uri=file:///path/to/canon-hv40-dv.dv ! deinterlace
mode=1 method=vfir ! ffmpegcolorspace ! autovideosink

and the same for method=linearblend before and after the patch. To my eyes, the
image seems very vertically shaky before and more stable after. I think there
may still be an issue (perhaps a workaround that was implemented?) in
linearblend that leads to visible combing in something like every other output
frame. Perhaps I will look into this shortly.

If you want to step through the frames to look more closely, I was outputting
to y4m by replacing autovideosink with y4menc ! filesink and then opening the
files in ffplay as I'm having some issues with y4mdec at the moment. :)

[1] http://people.xiph.org/~xiphmont/hv40_for_ed/canon-hv40-dv.dv

-- 
Configure bugmail: https://bugzilla.gnome.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the QA contact for the bug.
You are the assignee for the bug.