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lavfi: add colorkey_opencl filter

This is a direct port of the CPU filter.

Signed-off-by: Jarek Samic <cldfire3@gmail.com>
Signed-off-by: Mark Thompson <sw@jkqxz.net>
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Cldfire authored and fhvwy committed Apr 17, 2019
1 parent 782ae68 commit 1c46ab4815f8b32512ae5fa4fd9dc95fecd2a05d
@@ -3412,6 +3412,7 @@ bm3d_filter_select="dct"
boxblur_filter_deps="gpl"
boxblur_opencl_filter_deps="opencl gpl"
bs2b_filter_deps="libbs2b"
colorkey_opencl_filter_deps="opencl"
colormatrix_filter_deps="gpl"
convolution_opencl_filter_deps="opencl"
convolve_filter_deps="avcodec"
@end example
@end itemize

@section colorkey_opencl
RGB colorspace color keying.

The filter accepts the following options:

@table @option
@item color
The color which will be replaced with transparency.

@item similarity
Similarity percentage with the key color.

0.01 matches only the exact key color, while 1.0 matches everything.

@item blend
Blend percentage.

0.0 makes pixels either fully transparent, or not transparent at all.

Higher values result in semi-transparent pixels, with a higher transparency
the more similar the pixels color is to the key color.
@end table

@subsection Examples

@itemize
@item
Make every semi-green pixel in the input transparent with some slight blending:
@example
-i INPUT -vf "hwupload, colorkey_opencl=green:0.3:0.1, hwdownload" OUTPUT
@end example
@end itemize

@section overlay_opencl

Overlay one video on top of another.
@@ -176,6 +176,8 @@ OBJS-$(CONFIG_CODECVIEW_FILTER) += vf_codecview.o
OBJS-$(CONFIG_COLORBALANCE_FILTER) += vf_colorbalance.o
OBJS-$(CONFIG_COLORCHANNELMIXER_FILTER) += vf_colorchannelmixer.o
OBJS-$(CONFIG_COLORKEY_FILTER) += vf_colorkey.o
OBJS-$(CONFIG_COLORKEY_OPENCL_FILTER) += vf_colorkey_opencl.o opencl.o \
opencl/colorkey.o
OBJS-$(CONFIG_COLORLEVELS_FILTER) += vf_colorlevels.o
OBJS-$(CONFIG_COLORMATRIX_FILTER) += vf_colormatrix.o
OBJS-$(CONFIG_COLORSPACE_FILTER) += vf_colorspace.o colorspace.o colorspacedsp.o
@@ -165,6 +165,7 @@ extern AVFilter ff_vf_codecview;
extern AVFilter ff_vf_colorbalance;
extern AVFilter ff_vf_colorchannelmixer;
extern AVFilter ff_vf_colorkey;
extern AVFilter ff_vf_colorkey_opencl;
extern AVFilter ff_vf_colorlevels;
extern AVFilter ff_vf_colormatrix;
extern AVFilter ff_vf_colorspace;
@@ -0,0 +1,49 @@
/*
* 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 colorkey_blend(
__read_only image2d_t src,
__write_only image2d_t dst,
float4 colorkey_rgba,
float similarity,
float blend
) {
int2 loc = (int2)(get_global_id(0), get_global_id(1));
float4 pixel = read_imagef(src, sampler, loc);
float diff = distance(pixel.xyz, colorkey_rgba.xyz);

pixel.s3 = clamp((diff - similarity) / blend, 0.0f, 1.0f);
write_imagef(dst, loc, pixel);
}

__kernel void colorkey(
__read_only image2d_t src,
__write_only image2d_t dst,
float4 colorkey_rgba,
float similarity
) {
int2 loc = (int2)(get_global_id(0), get_global_id(1));
float4 pixel = read_imagef(src, sampler, loc);
float diff = distance(pixel.xyz, colorkey_rgba.xyz);

pixel.s3 = (diff > similarity) ? 1.0f : 0.0f;
write_imagef(dst, loc, pixel);
}
@@ -20,6 +20,7 @@
#define AVFILTER_OPENCL_SOURCE_H

extern const char *ff_opencl_source_avgblur;
extern const char *ff_opencl_source_colorkey;
extern const char *ff_opencl_source_colorspace_common;
extern const char *ff_opencl_source_convolution;
extern const char *ff_opencl_source_neighbor;
@@ -0,0 +1,244 @@
/*
* 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/opt.h"
#include "libavutil/imgutils.h"
#include "avfilter.h"
#include "formats.h"
#include "internal.h"
#include "opencl.h"
#include "opencl_source.h"
#include "video.h"

typedef struct ColorkeyOpenCLContext {
OpenCLFilterContext ocf;
// Whether or not the above `OpenCLFilterContext` has been initialized
int initialized;

cl_command_queue command_queue;
cl_kernel kernel_colorkey;

// The color we are supposed to replace with transparency
uint8_t colorkey_rgba[4];
// Stored as a normalized float for passing to the OpenCL kernel
cl_float4 colorkey_rgba_float;
// Similarity percentage compared to `colorkey_rgba`, ranging from `0.01` to `1.0`
// where `0.01` matches only the key color and `1.0` matches all colors
float similarity;
// Blending percentage where `0.0` results in fully transparent pixels, `1.0` results
// in fully opaque pixels, and numbers in between result in transparency that varies
// based on the similarity to the key color
float blend;
} ColorkeyOpenCLContext;

static int colorkey_opencl_init(AVFilterContext *avctx)
{
ColorkeyOpenCLContext *ctx = avctx->priv;
cl_int cle;
int err;

err = ff_opencl_filter_load_program(avctx, &ff_opencl_source_colorkey, 1);
if (err < 0)
goto fail;

ctx->command_queue = clCreateCommandQueue(
ctx->ocf.hwctx->context,
ctx->ocf.hwctx->device_id,
0,
&cle
);

CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to create OpenCL command queue %d.\n", cle);

if (ctx->blend > 0.0001) {
ctx->kernel_colorkey = clCreateKernel(ctx->ocf.program, "colorkey_blend", &cle);
CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to create colorkey_blend kernel: %d.\n", cle);
} else {
ctx->kernel_colorkey = clCreateKernel(ctx->ocf.program, "colorkey", &cle);
CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to create colorkey kernel: %d.\n", cle);
}

for (int i = 0; i < 4; ++i) {
ctx->colorkey_rgba_float.s[i] = (float)ctx->colorkey_rgba[i] / 255.0;
}

ctx->initialized = 1;
return 0;

fail:
if (ctx->command_queue)
clReleaseCommandQueue(ctx->command_queue);
if (ctx->kernel_colorkey)
clReleaseKernel(ctx->kernel_colorkey);
return err;
}

static int filter_frame(AVFilterLink *link, AVFrame *input_frame)
{
AVFilterContext *avctx = link->dst;
AVFilterLink *outlink = avctx->outputs[0];
ColorkeyOpenCLContext *colorkey_ctx = avctx->priv;
AVFrame *output_frame = NULL;
int err;
cl_int cle;
size_t global_work[2];
cl_mem src, dst;

if (!input_frame->hw_frames_ctx)
return AVERROR(EINVAL);

if (!colorkey_ctx->initialized) {
AVHWFramesContext *input_frames_ctx =
(AVHWFramesContext*)input_frame->hw_frames_ctx->data;
int fmt = input_frames_ctx->sw_format;

// Make sure the input is a format we support
if (fmt != AV_PIX_FMT_ARGB &&
fmt != AV_PIX_FMT_RGBA &&
fmt != AV_PIX_FMT_ABGR &&
fmt != AV_PIX_FMT_BGRA
) {
av_log(avctx, AV_LOG_ERROR, "unsupported (non-RGB) format in colorkey_opencl.\n");
err = AVERROR(ENOSYS);
goto fail;
}

err = colorkey_opencl_init(avctx);
if (err < 0)
goto fail;
}

// This filter only operates on RGB data and we know that will be on the first plane
src = (cl_mem)input_frame->data[0];
output_frame = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!output_frame) {
err = AVERROR(ENOMEM);
goto fail;
}
dst = (cl_mem)output_frame->data[0];

CL_SET_KERNEL_ARG(colorkey_ctx->kernel_colorkey, 0, cl_mem, &src);
CL_SET_KERNEL_ARG(colorkey_ctx->kernel_colorkey, 1, cl_mem, &dst);
CL_SET_KERNEL_ARG(colorkey_ctx->kernel_colorkey, 2, cl_float4, &colorkey_ctx->colorkey_rgba_float);
CL_SET_KERNEL_ARG(colorkey_ctx->kernel_colorkey, 3, float, &colorkey_ctx->similarity);
if (colorkey_ctx->blend > 0.0001) {
CL_SET_KERNEL_ARG(colorkey_ctx->kernel_colorkey, 4, float, &colorkey_ctx->blend);
}

err = ff_opencl_filter_work_size_from_image(avctx, global_work, input_frame, 0, 0);
if (err < 0)
goto fail;

cle = clEnqueueNDRangeKernel(
colorkey_ctx->command_queue,
colorkey_ctx->kernel_colorkey,
2,
NULL,
global_work,
NULL,
0,
NULL,
NULL
);

CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to enqueue colorkey kernel: %d.\n", cle);

// Run queued kernel
cle = clFinish(colorkey_ctx->command_queue);
CL_FAIL_ON_ERROR(AVERROR(EIO), "Failed to finish command queue: %d.\n", cle);

err = av_frame_copy_props(output_frame, input_frame);
if (err < 0)
goto fail;

av_frame_free(&input_frame);

return ff_filter_frame(outlink, output_frame);

fail:
clFinish(colorkey_ctx->command_queue);
av_frame_free(&input_frame);
av_frame_free(&output_frame);
return err;
}

static av_cold void colorkey_opencl_uninit(AVFilterContext *avctx)
{
ColorkeyOpenCLContext *ctx = avctx->priv;
cl_int cle;

if (ctx->kernel_colorkey) {
cle = clReleaseKernel(ctx->kernel_colorkey);
if (cle != CL_SUCCESS)
av_log(avctx, AV_LOG_ERROR, "Failed to release "
"kernel: %d.\n", cle);
}

if (ctx->command_queue) {
cle = clReleaseCommandQueue(ctx->command_queue);
if (cle != CL_SUCCESS)
av_log(avctx, AV_LOG_ERROR, "Failed to release "
"command queue: %d.\n", cle);
}

ff_opencl_filter_uninit(avctx);
}

static const AVFilterPad colorkey_opencl_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
.config_props = &ff_opencl_filter_config_input,
},
{ NULL }
};

static const AVFilterPad colorkey_opencl_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = &ff_opencl_filter_config_output,
},
{ NULL }
};

#define OFFSET(x) offsetof(ColorkeyOpenCLContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

static const AVOption colorkey_opencl_options[] = {
{ "color", "set the colorkey key color", OFFSET(colorkey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
{ "similarity", "set the colorkey similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
{ "blend", "set the colorkey key blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
{ NULL }
};

AVFILTER_DEFINE_CLASS(colorkey_opencl);

AVFilter ff_vf_colorkey_opencl = {
.name = "colorkey_opencl",
.description = NULL_IF_CONFIG_SMALL("Turns a certain color into transparency. Operates on RGB colors."),
.priv_size = sizeof(ColorkeyOpenCLContext),
.priv_class = &colorkey_opencl_class,
.init = &ff_opencl_filter_init,
.uninit = &colorkey_opencl_uninit,
.query_formats = &ff_opencl_filter_query_formats,
.inputs = colorkey_opencl_inputs,
.outputs = colorkey_opencl_outputs,
.flags_internal = FF_FILTER_FLAG_HWFRAME_AWARE
};

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