[FFmpeg-devel] [PATCH] avfilter: add gblur filter
Michael Niedermayer
michael at niedermayer.cc
Sun Sep 4 14:15:07 EEST 2016
On Thu, Sep 01, 2016 at 03:03:18PM +0200, Paul B Mahol wrote:
> Hi,
>
> patch attached.
> doc/filters.texi | 17 ++
> libavfilter/Makefile | 1
> libavfilter/allfilters.c | 1
> libavfilter/vf_gblur.c | 276 +++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 295 insertions(+)
> e14454fae179168294a89bf21ea0d2b1fb0fa41a 0001-avfilter-add-gblur-filter.patch
> From dca28955cfa774c0efed615cb5a0434f663731ec Mon Sep 17 00:00:00 2001
> From: Paul B Mahol <onemda at gmail.com>
> Date: Thu, 1 Sep 2016 01:18:45 +0200
> Subject: [PATCH] avfilter: add gblur filter
>
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> doc/filters.texi | 17 +++
> libavfilter/Makefile | 1 +
> libavfilter/allfilters.c | 1 +
> libavfilter/vf_gblur.c | 276 +++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 295 insertions(+)
> create mode 100644 libavfilter/vf_gblur.c
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 88c6f65..cf43edb 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -8231,6 +8231,23 @@ option may cause flicker since the B-Frames have often larger QP. Default is
>
> @end table
>
> + at section gblur
> +
> +Apply Gaussian blur filter.
> +
> +The filter accepts the following options:
> +
> + at table @option
> + at item sigma
> +Set sigma, standard deviation of Gaussian blur. Default is @code{0.5}.
> +
> + at item steps
> +Set number of steps for Gaussian approximation. Defauls is @code{4}.
> +
> + at item planes
> +Set which planes to filter. By default all planes are filtered.
> + at end table
> +
> @section geq
>
> The filter accepts the following options:
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index 81b40ac..0074ca3 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -183,6 +183,7 @@ OBJS-$(CONFIG_FRAMESTEP_FILTER) += vf_framestep.o
> OBJS-$(CONFIG_FREI0R_FILTER) += vf_frei0r.o
> OBJS-$(CONFIG_FSPP_FILTER) += vf_fspp.o
> OBJS-$(CONFIG_GEQ_FILTER) += vf_geq.o
> +OBJS-$(CONFIG_GBLUR_FILTER) += vf_gblur.o
> OBJS-$(CONFIG_GRADFUN_FILTER) += vf_gradfun.o
> OBJS-$(CONFIG_HALDCLUT_FILTER) += vf_lut3d.o dualinput.o framesync.o
> OBJS-$(CONFIG_HFLIP_FILTER) += vf_hflip.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index ee6f9cb..0234833 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -200,6 +200,7 @@ void avfilter_register_all(void)
> REGISTER_FILTER(FREI0R, frei0r, vf);
> REGISTER_FILTER(FSPP, fspp, vf);
> REGISTER_FILTER(GEQ, geq, vf);
> + REGISTER_FILTER(GBLUR, gblur, vf);
> REGISTER_FILTER(GRADFUN, gradfun, vf);
> REGISTER_FILTER(HALDCLUT, haldclut, vf);
> REGISTER_FILTER(HFLIP, hflip, vf);
> diff --git a/libavfilter/vf_gblur.c b/libavfilter/vf_gblur.c
> new file mode 100644
> index 0000000..fc316af
> --- /dev/null
> +++ b/libavfilter/vf_gblur.c
> @@ -0,0 +1,276 @@
> +/*
> + * Copyright (c) 2011 Pascal Getreuer
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include "libavutil/imgutils.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/pixdesc.h"
> +#include "avfilter.h"
> +#include "formats.h"
> +#include "internal.h"
> +#include "video.h"
> +
> +typedef struct GBlurContext {
> + const AVClass *class;
> +
> + float sigma;
> + int steps;
> + int planes;
> +
> + int depth;
> + int planewidth[4];
> + int planeheight[4];
> + float *buffer;
> + int nb_planes;
> +} GBlurContext;
> +
> +#define OFFSET(x) offsetof(GBlurContext, x)
> +#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
> +
> +static const AVOption gblur_options[] = {
> + { "sigma", "set sigma", OFFSET(sigma), AV_OPT_TYPE_FLOAT, {.dbl=0.5}, 0.0, 1024, FLAGS },
> + { "steps", "set number of steps", OFFSET(steps), AV_OPT_TYPE_INT, {.i64=4}, 1, 24, FLAGS },
> + { "planes", "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT, {.i64=0xF}, 0, 0xF, FLAGS },
> + { NULL }
> +};
> +
> +AVFILTER_DEFINE_CLASS(gblur);
> +
> +static void gaussianiir2d(float *buffer, int width, int height,
> + float sigma, int steps)
> +{
> + const int numpixels = width * height;
> + float nu, boundaryscale, postscale;
> + double lambda, dnu;
> + int i, x, y, step;
> + float *ptr;
> +
> + if (sigma <= 0 || steps < 0)
> + return;
> +
> + lambda = (sigma * sigma) / (2.0 * steps);
> + dnu = (1.0 + 2.0*lambda - sqrt(1.0 + 4.0 * lambda)) / (2.0 * lambda);
> + postscale = pow(dnu / lambda, 2*steps);
> + boundaryscale = 1.0 / (1.0 - dnu);
> + nu = (float)dnu;
> +
> + /* Filter horizontally along each row */
> + for (y = 0; y < height; y++) {
> + for (step = 0; step < steps; step++) {
> + ptr = buffer + width*y;
> + ptr[0] *= boundaryscale;
> +
> + /* Filter rightwards */
> + for (x = 1; x < width; x++)
> + ptr[x] += nu*ptr[x - 1];
> +
> + ptr[x = width - 1] *= boundaryscale;
> +
> + /* Filter leftwards */
> + for (; x > 0; x--)
> + ptr[x - 1] += nu*ptr[x];
> + }
> + }
> +
> + /* Filter vertically along each column */
> + for (x = 0; x < width; x++) {
> + for (step = 0; step < steps; step++) {
> + ptr = buffer + x;
> + ptr[0] *= boundaryscale;
> +
> + /* Filter downwards */
> + for (i = width; i < numpixels; i += width)
> + ptr[i] += nu*ptr[i - width];
> +
> + ptr[i = numpixels - width] *= boundaryscale;
> +
> + /* Filter upwards */
> + for (; i > 0; i -= width)
> + ptr[i - width] += nu*ptr[i];
> + }
> + }
This is a bit hard on the CPU cache, doing multiple colums at once
likely is faster
also this can be done much faster with SIMD
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
No great genius has ever existed without some touch of madness. -- Aristotle
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