avfilter: add pad opencl filter

Changelog

@@ -35,6 +35,7 @@ version <next>:
 - xfade video filter
 - xfade_opencl filter
 - afirsrc audio filter source
+- pad_opencl filter
 
 
 version 4.2:

configure

@@ -3535,6 +3535,7 @@ overlay_qsv_filter_deps="libmfx"
 overlay_qsv_filter_select="qsvvpp"
 overlay_vulkan_filter_deps="vulkan libglslang"
 owdenoise_filter_deps="gpl"
+pad_opencl_filter_deps="opencl"
 pan_filter_deps="swresample"
 perspective_filter_deps="gpl"
 phase_filter_deps="gpl"

doc/filters.texi

@@ -21172,6 +21172,83 @@ The inputs have same memory layout for color channels , the overlay has addition
 
 @end itemize
 
+@section pad_opencl
+
+Add paddings to the input image, and place the original input at the
+provided @var{x}, @var{y} coordinates.
+
+It accepts the following options:
+
+@table @option
+@item width, w
+@item height, h
+Specify an expression for the size of the output image with the
+paddings added. If the value for @var{width} or @var{height} is 0, the
+corresponding input size is used for the output.
+
+The @var{width} expression can reference the value set by the
+@var{height} expression, and vice versa.
+
+The default value of @var{width} and @var{height} is 0.
+
+@item x
+@item y
+Specify the offsets to place the input image at within the padded area,
+with respect to the top/left border of the output image.
+
+The @var{x} expression can reference the value set by the @var{y}
+expression, and vice versa.
+
+The default value of @var{x} and @var{y} is 0.
+
+If @var{x} or @var{y} evaluate to a negative number, they'll be changed
+so the input image is centered on the padded area.
+
+@item color
+Specify the color of the padded area. For the syntax of this option,
+check the @ref{color syntax,,"Color" section in the ffmpeg-utils
+manual,ffmpeg-utils}.
+
+@item aspect
+Pad to an aspect instead to a resolution.
+@end table
+
+The value for the @var{width}, @var{height}, @var{x}, and @var{y}
+options are expressions containing the following constants:
+
+@table @option
+@item in_w
+@item in_h
+The input video width and height.
+
+@item iw
+@item ih
+These are the same as @var{in_w} and @var{in_h}.
+
+@item out_w
+@item out_h
+The output width and height (the size of the padded area), as
+specified by the @var{width} and @var{height} expressions.
+
+@item ow
+@item oh
+These are the same as @var{out_w} and @var{out_h}.
+
+@item x
+@item y
+The x and y offsets as specified by the @var{x} and @var{y}
+expressions, or NAN if not yet specified.
+
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+@end table
+
 @section prewitt_opencl
 
 Apply the Prewitt operator (@url{https://en.wikipedia.org/wiki/Prewitt_operator}) to input video stream.

libavfilter/Makefile

@@ -329,6 +329,7 @@ OBJS-$(CONFIG_OVERLAY_QSV_FILTER)            += vf_overlay_qsv.o framesync.o
 OBJS-$(CONFIG_OVERLAY_VULKAN_FILTER)         += vf_overlay_vulkan.o vulkan.o
 OBJS-$(CONFIG_OWDENOISE_FILTER)              += vf_owdenoise.o
 OBJS-$(CONFIG_PAD_FILTER)                    += vf_pad.o
+OBJS-$(CONFIG_PAD_OPENCL_FILTER)             += vf_pad_opencl.o opencl.o opencl/pad.o
 OBJS-$(CONFIG_PALETTEGEN_FILTER)             += vf_palettegen.o
 OBJS-$(CONFIG_PALETTEUSE_FILTER)             += vf_paletteuse.o framesync.o
 OBJS-$(CONFIG_PERMS_FILTER)                  += f_perms.o

libavfilter/allfilters.c

@@ -313,6 +313,7 @@ extern AVFilter ff_vf_overlay_qsv;
 extern AVFilter ff_vf_overlay_vulkan;
 extern AVFilter ff_vf_owdenoise;
 extern AVFilter ff_vf_pad;
+extern AVFilter ff_vf_pad_opencl;
 extern AVFilter ff_vf_palettegen;
 extern AVFilter ff_vf_paletteuse;
 extern AVFilter ff_vf_perms;

libavfilter/opencl/pad.cl

+/*
+ * 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
+ */
+
+const sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE |
+                          CLK_FILTER_NEAREST;
+
+__kernel void pad (
+    __read_only  image2d_t src,
+    __write_only image2d_t dst,
+    float4 color,
+    int2 xy)
+{
+    int2 size_src = get_image_dim(src);
+    int2 loc = (int2)(get_global_id(0), get_global_id(1));
+    int2 src_pos = (int2)(get_global_id(0) - xy.x, get_global_id(1) - xy.y);
+    float4 pixel = loc.x >= size_src.x + xy.x ||
+                   loc.y >= size_src.y + xy.y ||
+                   loc.x < xy.x ||
+                   loc.y < xy.y ? color : read_imagef(src, sampler, src_pos);
+    write_imagef(dst, loc, pixel);
+}

libavfilter/opencl_source.h

@@ -27,6 +27,7 @@ extern const char *ff_opencl_source_deshake;
 extern const char *ff_opencl_source_neighbor;
 extern const char *ff_opencl_source_nlmeans;
 extern const char *ff_opencl_source_overlay;
+extern const char *ff_opencl_source_pad;
 extern const char *ff_opencl_source_tonemap;
 extern const char *ff_opencl_source_transpose;
 extern const char *ff_opencl_source_unsharp;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR  75
+#define LIBAVFILTER_VERSION_MINOR  76
 #define LIBAVFILTER_VERSION_MICRO 100