@@ -4,6 +4,7 @@ releases are sorted from youngest to oldest.

 version <next>:

 - deflicker video filter

 - doubleweave video filter

+- lumakey video filter

 version 3.3:

 - CrystalHD decoder moved to new decode API

@@ -9278,6 +9278,26 @@ Interpolate values using a tetrahedron.

 @end table

 @end table

+@section lumakey

+

+Turn certain luma values into transparency.

+

+The filter accepts the following options:

+

+@table @option

+@item threshold

+Set the luma which will be used as base for transparency.

+Default value is @code{0}.

+

+@item tolerance

+Set the range of luma values to be keyed out.

+Default value is @code{0}.

+

+@item softness

+Set the range of softness. Default value is @code{0}.

+Use this to control gradual transition from zero to full transparency.

+@end table

+

 @section lut, lutrgb, lutyuv

 Compute a look-up table for binding each pixel component input value

@@ -212,6 +212,7 @@ OBJS-$(CONFIG_INTERLEAVE_FILTER)             += f_interleave.o

 OBJS-$(CONFIG_KERNDEINT_FILTER)              += vf_kerndeint.o

 OBJS-$(CONFIG_LENSCORRECTION_FILTER)         += vf_lenscorrection.o

 OBJS-$(CONFIG_LOOP_FILTER)                   += f_loop.o

+OBJS-$(CONFIG_LUMAKEY_FILTER)                += vf_lumakey.o

 OBJS-$(CONFIG_LUT_FILTER)                    += vf_lut.o

 OBJS-$(CONFIG_LUT2_FILTER)                   += vf_lut2.o framesync.o

 OBJS-$(CONFIG_LUT3D_FILTER)                  += vf_lut3d.o

@@ -223,6 +223,7 @@ static void register_all(void)

     REGISTER_FILTER(KERNDEINT,      kerndeint,      vf);

     REGISTER_FILTER(LENSCORRECTION, lenscorrection, vf);

     REGISTER_FILTER(LOOP,           loop,           vf);

+    REGISTER_FILTER(LUMAKEY,        lumakey,        vf);

     REGISTER_FILTER(LUT,            lut,            vf);

     REGISTER_FILTER(LUT2,           lut2,           vf);

     REGISTER_FILTER(LUT3D,          lut3d,          vf);

@@ -30,7 +30,7 @@

 #include "libavutil/version.h"

 #define LIBAVFILTER_VERSION_MAJOR   6

-#define LIBAVFILTER_VERSION_MINOR  86

+#define LIBAVFILTER_VERSION_MINOR  87

 #define LIBAVFILTER_VERSION_MICRO 100

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

new file mode 100644

@@ -0,0 +1,201 @@

+/*

+ * Copyright (c) 2017 Paul B Mahol

+ *

+ * 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 "video.h"

+

+typedef struct LumakeyContext {

+    const AVClass *class;

+

+    int threshold;

+    int tolerance;

+    int softness;

+

+    int white;

+    int black;

+    int max;

+

+    int (*do_lumakey_slice)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);

+} LumakeyContext;

+

+static int do_lumakey_slice8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)

+{

+    LumakeyContext *s = ctx->priv;

+    AVFrame *frame = arg;

+    const int slice_start = (frame->height * jobnr) / nb_jobs;

+    const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;

+    uint8_t *alpha = frame->data[3] + slice_start * frame->linesize[3];

+    const uint8_t *luma = frame->data[0] + slice_start * frame->linesize[0];

+    const int so = s->softness;

+    const int w = s->white;

+    const int b = s->black;

+    int x, y;

+

+    for (y = slice_start; y < slice_end; y++) {

+        for (x = 0; x < frame->width; x++) {

+            if (luma[x] >= b && luma[x] <= w) {

+                alpha[x] = 0;

+            } else if (luma[x] > b - so && luma[x] < w + so) {

+                if (luma[x] < b) {

+                    alpha[x] = 255 - (luma[x] - b + so) * 255 / so;

+                } else {

+                    alpha[x] = (luma[x] - w) * 255 / so;

+                }

+            }

+        }

+        luma += frame->linesize[0];

+        alpha += frame->linesize[3];

+    }

+

+    return 0;

+}

+

+static int do_lumakey_slice16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)

+{

+    LumakeyContext *s = ctx->priv;

+    AVFrame *frame = arg;

+    const int slice_start = (frame->height * jobnr) / nb_jobs;

+    const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;

+    uint16_t *alpha = (uint16_t *)(frame->data[3] + slice_start * frame->linesize[3]);

+    const uint16_t *luma = (const uint16_t *)(frame->data[0] + slice_start * frame->linesize[0]);

+    const int so = s->softness;

+    const int w = s->white;

+    const int b = s->black;

+    const int m = s->max;

+    int x, y;

+

+    for (y = slice_start; y < slice_end; y++) {

+        for (x = 0; x < frame->width; x++) {

+            if (luma[x] >= b && luma[x] <= w) {

+                alpha[x] = 0;

+            } else if (luma[x] > b - so && luma[x] < w + so) {

+                if (luma[x] < b) {

+                    alpha[x] = m - (luma[x] - b + so) * m / so;

+                } else {

+                    alpha[x] = (luma[x] - w) * m / so;

+                }

+            }

+        }

+        luma += frame->linesize[0] / 2;

+        alpha += frame->linesize[3] / 2;

+    }

+

+    return 0;

+}

+

+static int config_input(AVFilterLink *inlink)

+{

+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);

+    AVFilterContext *ctx = inlink->dst;

+    LumakeyContext *s = ctx->priv;

+    int depth;

+

+    depth = desc->comp[0].depth;

+    if (depth == 8) {

+        s->white = av_clip_uint8(s->threshold + s->tolerance);

+        s->black = av_clip_uint8(s->threshold - s->tolerance);

+        s->do_lumakey_slice = do_lumakey_slice8;

+    } else {

+        s->max = (1 << depth) - 1;

+        s->white = av_clip(s->threshold + s->tolerance, 0, s->max);

+        s->black = av_clip(s->threshold - s->tolerance, 0, s->max);

+        s->do_lumakey_slice = do_lumakey_slice16;

+    }

+

+    return 0;

+}

+

+static int filter_frame(AVFilterLink *link, AVFrame *frame)

+{

+    AVFilterContext *ctx = link->dst;

+    LumakeyContext *s = ctx->priv;

+    int ret;

+

+    if (ret = av_frame_make_writable(frame))

+        return ret;

+

+    if (ret = ctx->internal->execute(ctx, s->do_lumakey_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(ctx))))

+        return ret;

+

+    return ff_filter_frame(ctx->outputs[0], frame);

+}

+

+static av_cold int query_formats(AVFilterContext *ctx)

+{

+    static const enum AVPixelFormat pixel_fmts[] = {

+        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,

+        AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA420P9,

+        AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA420P10,

+        AV_PIX_FMT_YUVA444P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA420P16,

+        AV_PIX_FMT_NONE

+    };

+    AVFilterFormats *formats;

+

+    formats = ff_make_format_list(pixel_fmts);

+    if (!formats)

+        return AVERROR(ENOMEM);

+

+    return ff_set_common_formats(ctx, formats);

+}

+

+static const AVFilterPad lumakey_inputs[] = {

+    {

+        .name         = "default",

+        .type         = AVMEDIA_TYPE_VIDEO,

+        .filter_frame = filter_frame,

+        .config_props = config_input,

+    },

+    { NULL }

+};

+

+static const AVFilterPad lumakey_outputs[] = {

+    {

+        .name          = "default",

+        .type          = AVMEDIA_TYPE_VIDEO,

+    },

+    { NULL }

+};

+

+#define OFFSET(x) offsetof(LumakeyContext, x)

+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM

+

+static const AVOption lumakey_options[] = {

+    { "threshold", "set the threshold value", OFFSET(threshold), AV_OPT_TYPE_INT, {.i64=0}, 0, UINT16_MAX, FLAGS },

+    { "tolerance", "set the tolerance value", OFFSET(tolerance), AV_OPT_TYPE_INT, {.i64=1}, 0, UINT16_MAX, FLAGS },

+    { "softness",  "set the softness value",  OFFSET(softness),  AV_OPT_TYPE_INT, {.i64=0}, 0, UINT16_MAX, FLAGS },

+    { NULL }

+};

+

+AVFILTER_DEFINE_CLASS(lumakey);

+

+AVFilter ff_vf_lumakey = {

+    .name          = "lumakey",

+    .description   = NULL_IF_CONFIG_SMALL("Turns a certain luma into transparency."),

+    .priv_size     = sizeof(LumakeyContext),

+    .priv_class    = &lumakey_class,

+    .query_formats = query_formats,

+    .inputs        = lumakey_inputs,

+    .outputs       = lumakey_outputs,

+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,

+};