[FFmpeg-devel] [PATCH] avfilter: add deband filter

[Paul B Mahol]

Dana 15. 7. 2015. 16:01 osoba "James Darnley" <james.darnley at gmail.com>
napisala je:
>
> On 2015-07-15 00:06, Paul B Mahol wrote:
> > Signed-off-by: Paul B Mahol <onemda at gmail.com>
> > ---
> >  doc/filters.texi         |  35 ++++++
> >  libavfilter/Makefile     |   1 +
> >  libavfilter/allfilters.c |   1 +
> >  libavfilter/vf_deband.c  | 312
+++++++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 349 insertions(+)
> >  create mode 100644 libavfilter/vf_deband.c
> >
> > diff --git a/doc/filters.texi b/doc/filters.texi
> > index 9f7b976..0a07735 100644
> > --- a/doc/filters.texi
> > +++ b/doc/filters.texi
> > @@ -3678,6 +3678,41 @@ Violent denoise using a block size of
@code{16x16}:
> >  dctdnoiz=15:n=4
> >  @end example
> >
> > + at section deband
> > +
> > +Remove banding artifacts from input video.
> > +It works by replacing banded pixels with average value of referenced
pixels.
> > +
> > +The filter accepts the following options:
> > +
> > + at table @option
> > + at item 1thr
> > + at item 2thr
> > + at item 3thr
> > + at item 4thr
> > +Set banding detection threshold for each plane. Default is 0.02. Range
from
> > +which value can be selected is from 0.008 to 0.5.
>
> I would suggest dropping the second "from" or rewording the third
> sentence as "Valid range is 0.008 to 0.5."
>
> > +If difference between current pixel and reference pixel is less than
threshold,
> > +it will be considered as banded.
> > +
> > + at item range, r
> > +Banding detection range in pixels. Default is 16. If positive, random
number
> > +from range 0 to set value will be picked. If negative, exact of
absolute value
> > +will be used.
> > +The range defines square of four pixels around current pixel.
>
> "If positive, random number in range 0 to r will be used."
>
> "If negative, exact absolute value will be used."
>
> > + at item direction, d
> > +Set direction from which four pixel will be compared. If positive,
random
> > +direction from 0 to set direction will be picked. If negative, exact of
> > +absolute value will be picked.
>
> Similar to above.  Also, what does the direction mean?  It's a float and
> looks like it represents radians (there is a sine/cosine pair below).
> The range is -2*PI..2*PI (should that also be mentioned here?) but what
> does the 0 represent? Looking at the code 0 is up then increasing moves
> in a clockwise direction.
>
> > + at item blur
> > +If enabled current pixel is compared with average value of all four
> > +surrounding pixels. By default is enabled. If disabled current pixel is
>
> "The default is enabled."
>
> > diff --git a/libavfilter/vf_deband.c b/libavfilter/vf_deband.c
> > new file mode 100644
> > index 0000000..1fd05d1
> > --- /dev/null
> > +++ b/libavfilter/vf_deband.c
> > @@ -0,0 +1,312 @@
> > +/*
> > + * Copyright (c) 2015 Niklas Haas
> > + * Copyright (c) 2015 Paul B Mahol
> > + *
> > + * Permission is hereby granted, free of charge, to any person
obtaining a copy
> > + * of this software and associated documentation files (the
"Software"), to deal
> > + * in the Software without restriction, including without limitation
the rights
> > + * to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell
> > + * copies of the Software, and to permit persons to whom the Software
is
> > + * furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice shall be
included in
> > + * all copies or substantial portions of the Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
SHALL THE
> > + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM,
> > + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE
> > + * SOFTWARE.
> > + */
>
> This is the MIT license, right?  Do we specifically note these anywhere?
>
>

Nope, imho not needed.

>
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