libavfilter/vf_lumakey.c
dfc4ce5f
 /*
  * 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,
 };