[FFmpeg-devel] [PATCH v2] avfilter/delogo: Set default band to 1

[Jean Delvare]

On Thu, 8 Oct 2015 12:20:25 +0200, Hendrik Leppkes wrote:
> On Thu, Oct 8, 2015 at 11:30 AM, Stefano Sabatini <stefasab at gmail.com> wrote:
> > On date Wednesday 2015-10-07 15:03:32 +0200, Jean Delvare encoded:
> >> The original interpolation algorithm behaved poorly on the borders and
> >> did not even guarantee continuity at the borders. For this reason, a
> >> second interpolation/blending pass was required on the borders to make
> >> them seamless.
> >>
> >> However, since the interpolation algorithm was improved in June 2013,
> >> the border issues no longer exist. The new algorithm does guarantee
> >> continuity at the borders, making the second pass useless. A larger
> >> band always increases the cumulated interpolation error. In most cases
> >> it also increases the average interpolation error, even though the
> >> samples in the band are only partially interpolated.
> >>
> >> For this reason I would like to get rid of the "band" parameter. As a
> >> first step, let's change its default value from 4 to 1 and document it
> >> as deprecated.
> >>
> >> I have benchmarked this change on a combination of input sources and
> >> realistic logo areas. Lowering the band value from 4 to 1 resulted in
> >> 8 to 39 % less interpolation error per frame (or 1 to 34 % less
> >> interpolation error per luma sample.)
> >>
> >> Signed-off-by: Jean Delvare <jdelvare at suse.de>
> >> ---
> >> Changes since v1:
> >>  * Added #ifs so that the deprecated options are dropped automatically
> >>    on next major version of libavfilter (suggested by Stefano Sabatini)
> >>
> >>  doc/filters.texi        |    4 +++-
> >>  libavfilter/vf_delogo.c |   17 +++++++++++++++--
> >>  2 files changed, 18 insertions(+), 3 deletions(-)
> >
> > Thanks, applied.
> 
> This seems to have broken FATE, ie:
> http://fate.ffmpeg.org/report.cgi?time=20151008101706&slot=x86_32-mingw-w64-dll-windows-native

Oops, yes, sorry. The different result is intended. I meant to update
the test result but forgot to do so. Patch coming.

-- 
Jean Delvare
SUSE L3 Support