[FFmpeg-devel] [PATCH] doc/filters: add documentation to all existing OpenCL filters, except tonemap filter

Danil Iashchenko danyaschenko at gmail.com
Thu Jul 5 17:11:40 EEST 2018


add documentation to all existing OpenCL filters
---
>I like this patch, the other thing, is it have any plan to update
>openCL part like VAAPI (https://trac.ffmpeg.org/wiki/Hardware/VAAPI)
>in https://trac.ffmpeg.org/wiki/HWAccelIntro, thanks.
I am going to add it during the next week, thanks!

>Why not for tonemap_opencl?
Added.

>Since these filters are distinct, please list options as well, since their software counterparts could conceivably change. Option entries should include default value, range, and semantic.
Fixed.

>Why are all examples of filters, that operate upon a single stream, shown within -filter_complex? '-vf' is preferred.
Fixed.

>P.S. Once this new section is created, program_opencl entry should be shifted there, in a separate patch.
Shifted to opencl section.

Thanks, Danil.

 doc/filters.texi | 741 +++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 611 insertions(+), 130 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index fb5f3ee..16a350a 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -12917,136 +12917,6 @@ Set value which will be multiplied with filtered result.
 Set value which will be added to filtered result.
 @end table
 
- at anchor{program_opencl}
- at section program_opencl
-
-Filter video using an OpenCL program.
-
- at table @option
-
- at item source
-OpenCL program source file.
-
- at item kernel
-Kernel name in program.
-
- at item inputs
-Number of inputs to the filter.  Defaults to 1.
-
- at item size, s
-Size of output frames.  Defaults to the same as the first input.
-
- at end table
-
-The program source file must contain a kernel function with the given name,
-which will be run once for each plane of the output.  Each run on a plane
-gets enqueued as a separate 2D global NDRange with one work-item for each
-pixel to be generated.  The global ID offset for each work-item is therefore
-the coordinates of a pixel in the destination image.
-
-The kernel function needs to take the following arguments:
- at itemize
- at item
-Destination image, @var{__write_only image2d_t}.
-
-This image will become the output; the kernel should write all of it.
- at item
-Frame index, @var{unsigned int}.
-
-This is a counter starting from zero and increasing by one for each frame.
- at item
-Source images, @var{__read_only image2d_t}.
-
-These are the most recent images on each input.  The kernel may read from
-them to generate the output, but they can't be written to.
- at end itemize
-
-Example programs:
-
- at itemize
- at item
-Copy the input to the output (output must be the same size as the input).
- at verbatim
-__kernel void copy(__write_only image2d_t destination,
-                   unsigned int index,
-                   __read_only  image2d_t source)
-{
-    const sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE;
-
-    int2 location = (int2)(get_global_id(0), get_global_id(1));
-
-    float4 value = read_imagef(source, sampler, location);
-
-    write_imagef(destination, location, value);
-}
- at end verbatim
-
- at item
-Apply a simple transformation, rotating the input by an amount increasing
-with the index counter.  Pixel values are linearly interpolated by the
-sampler, and the output need not have the same dimensions as the input.
- at verbatim
-__kernel void rotate_image(__write_only image2d_t dst,
-                           unsigned int index,
-                           __read_only  image2d_t src)
-{
-    const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
-                               CLK_FILTER_LINEAR);
-
-    float angle = (float)index / 100.0f;
-
-    float2 dst_dim = convert_float2(get_image_dim(dst));
-    float2 src_dim = convert_float2(get_image_dim(src));
-
-    float2 dst_cen = dst_dim / 2.0f;
-    float2 src_cen = src_dim / 2.0f;
-
-    int2   dst_loc = (int2)(get_global_id(0), get_global_id(1));
-
-    float2 dst_pos = convert_float2(dst_loc) - dst_cen;
-    float2 src_pos = {
-        cos(angle) * dst_pos.x - sin(angle) * dst_pos.y,
-        sin(angle) * dst_pos.x + cos(angle) * dst_pos.y
-    };
-    src_pos = src_pos * src_dim / dst_dim;
-
-    float2 src_loc = src_pos + src_cen;
-
-    if (src_loc.x < 0.0f      || src_loc.y < 0.0f ||
-        src_loc.x > src_dim.x || src_loc.y > src_dim.y)
-        write_imagef(dst, dst_loc, 0.5f);
-    else
-        write_imagef(dst, dst_loc, read_imagef(src, sampler, src_loc));
-}
- at end verbatim
-
- at item
-Blend two inputs together, with the amount of each input used varying
-with the index counter.
- at verbatim
-__kernel void blend_images(__write_only image2d_t dst,
-                           unsigned int index,
-                           __read_only  image2d_t src1,
-                           __read_only  image2d_t src2)
-{
-    const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
-                               CLK_FILTER_LINEAR);
-
-    float blend = (cos((float)index / 50.0f) + 1.0f) / 2.0f;
-
-    int2  dst_loc = (int2)(get_global_id(0), get_global_id(1));
-    int2 src1_loc = dst_loc * get_image_dim(src1) / get_image_dim(dst);
-    int2 src2_loc = dst_loc * get_image_dim(src2) / get_image_dim(dst);
-
-    float4 val1 = read_imagef(src1, sampler, src1_loc);
-    float4 val2 = read_imagef(src2, sampler, src2_loc);
-
-    write_imagef(dst, dst_loc, val1 * blend + val2 * (1.0f - blend));
-}
- at end verbatim
-
- at end itemize
-
 @section pseudocolor
 
 Alter frame colors in video with pseudocolors.
@@ -17422,6 +17292,617 @@ pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
 
 @c man end VIDEO FILTERS
 
+ at chapter OpenCL Video Filters
+ at c man begin OPENCL VIDEO FILTERS
+
+Below is a description of the currently available OpenCL video filters.
+
+To enable compilation of these filters you need to configure FFmpeg with
+ at code{--enable-opencl}.
+
+ at section avgblur_opencl
+
+Apply average blur filter.
+
+The filter accepts the following options:
+
+ at table @option
+ at item sizeX
+Set horizontal kernel size. By default value is @code{1}.
+
+ at item planes
+Set which planes to filter. By default all planes are filtered.
+
+ at item sizeY
+Set vertical kernel size, if zero it will be same as @code{sizeX}.
+By default value is @code{0}.
+ at end table
+
+ at subsection Example
+
+ at itemize
+ at item
+Apply average blur filter with sizeX and sizeY set to 3
+ at example
+-i INPUT -vf "hwupload, avgblur_opencl=3, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at section boxblur_opencl
+
+Apply a boxblur algorithm to the input video.
+
+It accepts the following parameters:
+
+ at table @option
+
+ at item luma_radius, lr
+ at item luma_power, lp
+ at item chroma_radius, cr
+ at item chroma_power, cp
+ at item alpha_radius, ar
+ at item alpha_power, ap
+
+ at end table
+
+A description of the accepted options follows.
+
+ at table @option
+ at item luma_radius, lr
+ at item chroma_radius, cr
+ at item alpha_radius, ar
+Set an expression for the box radius in pixels used for blurring the
+corresponding input plane.
+
+The radius value must be a non-negative number, and must not be
+greater than the value of the expression @code{min(w,h)/2} for the
+luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma
+planes.
+
+Default value for @option{luma_radius} is "2". If not specified,
+ at option{chroma_radius} and @option{alpha_radius} default to the
+corresponding value set for @option{luma_radius}.
+
+The expressions can contain the following constants:
+ at table @option
+ at item w
+ at item h
+The input width and height in pixels.
+
+ at item cw
+ at item ch
+The input chroma image width and height in pixels.
+
+ at item hsub
+ at item vsub
+The horizontal and vertical chroma subsample values. For example, for the
+pixel format "yuv422p", @var{hsub} is 2 and @var{vsub} is 1.
+ at end table
+
+ at item luma_power, lp
+ at item chroma_power, cp
+ at item alpha_power, ap
+Specify how many times the boxblur filter is applied to the
+corresponding plane.
+
+Default value for @option{luma_power} is 2. If not specified,
+ at option{chroma_power} and @option{alpha_power} default to the
+corresponding value set for @option{luma_power}.
+
+A value of 0 will disable the effect.
+ at end table
+
+ at subsection Examples
+
+ at itemize
+ at item
+Apply a boxblur filter with the luma, chroma, and alpha radius
+set to 2:
+ at example
+-i INPUT -vf "hwupload, boxblur_opencl=luma_radius=2:luma_power=1, hwdownload" OUTPUT
+-i INPUT -vf "hwupload, boxblur_opencl=2:1, hwdownload" OUTPUT
+ at end example
+
+ at item
+Set the luma radius to 2, and alpha and chroma radius to 0:
+ at example
+-i INPUT -vf "hwupload, boxblur_opencl=2:1:cr=0:ar=0, hwdownload" OUTPUT
+ at end example
+
+ at item
+Set the luma and chroma radius to a fraction of the video dimension:
+ at example
+-i INPUT -vf "hwupload, boxblur_opencl=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at section convolution_opencl
+
+Apply convolution of 3x3, 5x5, 7x7 or horizontal/vertical up to 49 elements.
+
+The filter accepts the following options:
+
+ at table @option
+ at item 0m
+ at item 1m
+ at item 2m
+ at item 3m
+Set matrix for each plane.
+Matrix is sequence of 9, 25 or 49 signed integers in @var{square} mode,
+and from 1 to 49 odd number of signed integers in @var{row} mode.
+
+ at item 0rdiv
+ at item 1rdiv
+ at item 2rdiv
+ at item 3rdiv
+Set multiplier for calculated value for each plane.
+If unset or 0, it will be sum of all matrix elements.
+
+ at item 0bias
+ at item 1bias
+ at item 2bias
+ at item 3bias
+Set bias for each plane. This value is added to the result of the multiplication.
+Useful for making the overall image brighter or darker. Default is 0.0.
+
+ at item 0mode
+ at item 1mode
+ at item 2mode
+ at item 3mode
+Set matrix mode for each plane. Can be @var{square}, @var{row} or @var{column}.
+Default is @var{square}.
+ at end table
+
+ at subsection Examples
+
+ at itemize
+ at item
+Apply sharpen:
+ at example
+-i INPUT -vf "hwupload, convolution_opencl=0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0, hwdownload" OUTPUT
+ at end example
+
+ at item
+Apply blur:
+ at example
+-i INPUT -vf "hwupload, convolution_opencl=1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1 1 1 1 1 1 1 1 1:1/9:1/9:1/9:1/9, hwdownload" OUTPUT
+ at end example
+
+ at item
+Apply edge enhance:
+ at example
+-i INPUT -vf "hwupload, convolution_opencl=0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0 0 0:5:1:1:1:0:128:128:128, hwdownload" OUTPUT
+ at end example
+
+ at item
+Apply edge detect:
+ at example
+-i INPUT -vf "hwupload, convolution_opencl=0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0 1 0:5:5:5:1:0:128:128:128, hwdownload" OUTPUT
+ at end example
+
+ at item
+Apply laplacian edge detector which includes diagonals:
+ at example
+-i INPUT -vf "hwupload, convolution_opencl=1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:1 1 1 1 -8 1 1 1 1:5:5:5:1:0:128:128:0, hwdownload" OUTPUT
+ at end example
+
+ at item
+Apply emboss:
+ at example
+-i INPUT -vf "hwupload, convolution_opencl=-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0 1 2, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at section overlay_opencl
+
+Overlay one video on top of another.
+
+It takes two inputs and has one output. The first input is the "main"
+video on which the second input is overlaid.
+
+The filter accepts the following options:
+
+ at table @option
+
+ at item x
+Set the x coordinate of the overlaid video on the main video
+By default value is @code{0}.
+
+ at item y
+Set the x coordinate of the overlaid video on the main video
+By default value is @code{0}.
+
+ at end table
+
+ at subsection Example
+
+ at itemize
+ at item
+Insert a transparent PNG logo in the bottom left corner of the input
+ at example
+-i INPUT -i LOGO -filter_complex "[0:v]hwupload[a],[1:v]hwupload[b],[a][b]overlay_opencl[out],[out]hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at section prewitt_opencl
+
+Apply prewitt operator to input video stream.
+
+The filter accepts the following option:
+
+ at table @option
+ at item planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value @code{0xf}, all planes will be processed.
+
+ at item scale
+Set value which will be multiplied with filtered result.
+By default value is @code{1}.
+
+ at item delta
+Set value which will be added to filtered result.
+By default value is @code{0}.
+ at end table
+
+ at subsection Example
+
+ at itemize
+ at item
+Apply prewitt operator with scale set to 2 and delta set to 10
+ at example
+-i INPUT -vf "hwupload, prewitt_opencl=scale=2:delta=10, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at anchor{program_opencl}
+ at section program_opencl
+
+Filter video using an OpenCL program.
+
+ at table @option
+
+ at item source
+OpenCL program source file.
+
+ at item kernel
+Kernel name in program.
+
+ at item inputs
+Number of inputs to the filter.  Defaults to 1.
+
+ at item size, s
+Size of output frames.  Defaults to the same as the first input.
+
+ at end table
+
+The program source file must contain a kernel function with the given name,
+which will be run once for each plane of the output.  Each run on a plane
+gets enqueued as a separate 2D global NDRange with one work-item for each
+pixel to be generated.  The global ID offset for each work-item is therefore
+the coordinates of a pixel in the destination image.
+
+The kernel function needs to take the following arguments:
+ at itemize
+ at item
+Destination image, @var{__write_only image2d_t}.
+
+This image will become the output; the kernel should write all of it.
+ at item
+Frame index, @var{unsigned int}.
+
+This is a counter starting from zero and increasing by one for each frame.
+ at item
+Source images, @var{__read_only image2d_t}.
+
+These are the most recent images on each input.  The kernel may read from
+them to generate the output, but they can't be written to.
+ at end itemize
+
+ at subsection Example programs:
+
+ at itemize
+ at item
+Copy the input to the output (output must be the same size as the input).
+ at verbatim
+__kernel void copy(__write_only image2d_t destination,
+                   unsigned int index,
+                   __read_only  image2d_t source)
+{
+    const sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE;
+
+    int2 location = (int2)(get_global_id(0), get_global_id(1));
+
+    float4 value = read_imagef(source, sampler, location);
+
+    write_imagef(destination, location, value);
+}
+ at end verbatim
+
+ at item
+Apply a simple transformation, rotating the input by an amount increasing
+with the index counter.  Pixel values are linearly interpolated by the
+sampler, and the output need not have the same dimensions as the input.
+ at verbatim
+__kernel void rotate_image(__write_only image2d_t dst,
+                           unsigned int index,
+                           __read_only  image2d_t src)
+{
+    const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
+                               CLK_FILTER_LINEAR);
+
+    float angle = (float)index / 100.0f;
+
+    float2 dst_dim = convert_float2(get_image_dim(dst));
+    float2 src_dim = convert_float2(get_image_dim(src));
+
+    float2 dst_cen = dst_dim / 2.0f;
+    float2 src_cen = src_dim / 2.0f;
+
+    int2   dst_loc = (int2)(get_global_id(0), get_global_id(1));
+
+    float2 dst_pos = convert_float2(dst_loc) - dst_cen;
+    float2 src_pos = {
+        cos(angle) * dst_pos.x - sin(angle) * dst_pos.y,
+        sin(angle) * dst_pos.x + cos(angle) * dst_pos.y
+    };
+    src_pos = src_pos * src_dim / dst_dim;
+
+    float2 src_loc = src_pos + src_cen;
+
+    if (src_loc.x < 0.0f      || src_loc.y < 0.0f ||
+        src_loc.x > src_dim.x || src_loc.y > src_dim.y)
+        write_imagef(dst, dst_loc, 0.5f);
+    else
+        write_imagef(dst, dst_loc, read_imagef(src, sampler, src_loc));
+}
+ at end verbatim
+
+ at item
+Blend two inputs together, with the amount of each input used varying
+with the index counter.
+ at verbatim
+__kernel void blend_images(__write_only image2d_t dst,
+                           unsigned int index,
+                           __read_only  image2d_t src1,
+                           __read_only  image2d_t src2)
+{
+    const sampler_t sampler = (CLK_NORMALIZED_COORDS_FALSE |
+                               CLK_FILTER_LINEAR);
+
+    float blend = (cos((float)index / 50.0f) + 1.0f) / 2.0f;
+
+    int2  dst_loc = (int2)(get_global_id(0), get_global_id(1));
+    int2 src1_loc = dst_loc * get_image_dim(src1) / get_image_dim(dst);
+    int2 src2_loc = dst_loc * get_image_dim(src2) / get_image_dim(dst);
+
+    float4 val1 = read_imagef(src1, sampler, src1_loc);
+    float4 val2 = read_imagef(src2, sampler, src2_loc);
+
+    write_imagef(dst, dst_loc, val1 * blend + val2 * (1.0f - blend));
+}
+ at end verbatim
+
+ at end itemize
+
+ at section roberts_opencl
+Apply roberts cross operator to input video stream.
+
+The filter accepts the following option:
+
+ at table @option
+ at item planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value @code{0xf}, all planes will be processed.
+
+ at item scale
+Set value which will be multiplied with filtered result.
+By default value is @code{1}.
+
+ at item delta
+Set value which will be added to filtered result.
+By default value is @code{0}.
+ at end table
+
+ at subsection Example
+
+ at itemize
+ at item
+Apply roberts cross operator with scale set to 2 and delta set to 10
+ at example
+-i INPUT -vf "hwupload, roberts_opencl=scale=2:delta=10, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at section sobel_opencl
+
+Apply sobel operator to input video stream.
+
+The filter accepts the following option:
+
+ at table @option
+ at item planes
+Set which planes will be processed, unprocessed planes will be copied.
+By default value @code{0xf}, all planes will be processed.
+
+ at item scale
+Set value which will be multiplied with filtered result.
+By default value is @code{1}.
+
+ at item delta
+Set value which will be added to filtered result.
+By default value is @code{0}.
+ at end table
+
+ at subsection Example
+
+ at itemize
+ at item
+Apply sobel operator with scale set to 2 and delta set to 10
+ at example
+-i INPUT -vf "hwupload, sobel_opencl=scale=2:delta=10, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at section tonemap_opencl
+Tone map colors from different dynamic ranges.
+
+ at subsection Options
+The filter accepts the following options.
+
+ at table @option
+ at item tonemap
+Set the tone map algorithm to use.
+
+Possible values are:
+ at table @var
+ at item none
+Do not apply any tone map, only desaturate overbright pixels.
+
+ at item clip
+Hard-clip any out-of-range values. Use it for perfect color accuracy for
+in-range values, while distorting out-of-range values.
+
+ at item linear
+Stretch the entire reference gamut to a linear multiple of the display.
+
+ at item gamma
+Fit a logarithmic transfer between the tone curves.
+
+ at item reinhard
+Preserve overall image brightness with a simple curve, using nonlinear
+contrast, which results in flattening details and degrading color accuracy.
+
+ at item hable
+Preserve both dark and bright details better than @var{reinhard}, at the cost
+of slightly darkening everything. Use it when detail preservation is more
+important than color and brightness accuracy.
+
+ at item mobius
+Smoothly map out-of-range values, while retaining contrast and colors for
+in-range material as much as possible. Use it when color accuracy is more
+important than detail preservation.
+ at end table
+
+Default is none.
+
+ at item param
+Tune the tone mapping algorithm.
+
+This affects the following algorithms:
+ at table @var
+ at item none
+Ignored.
+
+ at item linear
+Specifies the scale factor to use while stretching.
+Default to 1.0.
+
+ at item gamma
+Specifies the exponent of the function.
+Default to 1.8.
+
+ at item clip
+Specify an extra linear coefficient to multiply into the signal before clipping.
+Default to 1.0.
+
+ at item reinhard
+Specify the local contrast coefficient at the display peak.
+Default to 0.5, which means that in-gamut values will be about half as bright
+as when clipping.
+
+ at item hable
+Ignored.
+
+ at item mobius
+Specify the transition point from linear to mobius transform. Every value
+below this point is guaranteed to be mapped 1:1. The higher the value, the
+more accurate the result will be, at the cost of losing bright details.
+Default to 0.3, which due to the steep initial slope still preserves in-range
+colors fairly accurately.
+ at end table
+
+ at item desat
+Apply desaturation for highlights that exceed this level of brightness. The
+higher the parameter, the more color information will be preserved. This
+setting helps prevent unnaturally blown-out colors for super-highlights, by
+(smoothly) turning into white instead. This makes images feel more natural,
+at the cost of reducing information about out-of-range colors.
+
+The default of 2.0 is somewhat conservative and will mostly just apply to
+skies or directly sunlit surfaces. A setting of 0.0 disables this option.
+
+This option works only if the input frame has a supported color tag.
+
+ at item peak
+Override signal/nominal/reference peak with this value. Useful when the
+embedded peak information in display metadata is not reliable or when tone
+mapping from a lower range to a higher range.
+ at end table
+
+ at section unsharp_opencl
+
+Sharpen or blur the input video.
+
+It accepts the following parameters:
+
+ at table @option
+ at item luma_msize_x, lx
+Set the luma matrix horizontal size. It must be an odd integer between
+ at code{3} and @code{23}. The default value is @code{5}.
+
+ at item luma_msize_y, ly
+Set the luma matrix vertical size. It must be an odd integer between @code{3}
+and @code{23}. The default value is @code{5}.
+
+ at item luma_amount, la
+Set the luma effect strength. It must be a floating point number, reasonable
+values lay between @code{-1.5} and @code{1.5}.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is @code{1.0}.
+
+ at item chroma_msize_x, cx
+Set the chroma matrix horizontal size. It must be an odd integer
+between @code{3} and @code{23}. The default value is @code{5}.
+
+ at item chroma_msize_y, cy
+Set the chroma matrix vertical size. It must be an odd integer
+between @code{3} and @code{23}. The default value is @code{5}.
+
+ at item chroma_amount, ca
+Set the chroma effect strength. It must be a floating point number, reasonable
+values lay between @code{-1.5} and @code{1.5}.
+
+Negative values will blur the input video, while positive values will
+sharpen it, a value of zero will disable the effect.
+
+Default value is @code{0.0}.
+
+ at end table
+
+All parameters are optional and default to the equivalent of the
+string '5:5:1.0:5:5:0.0'.
+
+ at subsection Examples
+
+ at itemize
+ at item
+Apply strong luma sharpen effect:
+ at example
+-i INPUT -vf "hwupload, unsharp_opencl=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5, hwdownload" OUTPUT
+ at end example
+
+ at item
+Apply a strong blur of both luma and chroma parameters:
+ at example
+-i INPUT -vf "hwupload, unsharp_opencl=7:7:-2:7:7:-2, hwdownload" OUTPUT
+ at end example
+ at end itemize
+
+ at c man end OPENCL VIDEO FILTERS
+
 @chapter Video Sources
 @c man begin VIDEO SOURCES
 
-- 
2.7.4



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