/*
* 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,
};