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path: root/libavfilter/vf_chromakey.c (plain)
blob: 88414783bc8001bb39f7f53e02aa6731dae403ab
1/*
2 * Copyright (c) 2015 Timo Rothenpieler <timo@rothenpieler.org>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "libavutil/opt.h"
22#include "libavutil/imgutils.h"
23#include "avfilter.h"
24#include "formats.h"
25#include "internal.h"
26#include "video.h"
27
28typedef struct ChromakeyContext {
29 const AVClass *class;
30
31 uint8_t chromakey_rgba[4];
32 uint8_t chromakey_uv[2];
33
34 float similarity;
35 float blend;
36
37 int is_yuv;
38
39 int hsub_log2;
40 int vsub_log2;
41} ChromakeyContext;
42
43static uint8_t do_chromakey_pixel(ChromakeyContext *ctx, uint8_t u[9], uint8_t v[9])
44{
45 double diff = 0.0;
46 int du, dv, i;
47
48 for (i = 0; i < 9; ++i) {
49 du = (int)u[i] - ctx->chromakey_uv[0];
50 dv = (int)v[i] - ctx->chromakey_uv[1];
51
52 diff += sqrt((du * du + dv * dv) / (255.0 * 255.0));
53 }
54
55 diff /= 9.0;
56
57 if (ctx->blend > 0.0001) {
58 return av_clipd((diff - ctx->similarity) / ctx->blend, 0.0, 1.0) * 255.0;
59 } else {
60 return (diff > ctx->similarity) ? 255 : 0;
61 }
62}
63
64static av_always_inline void get_pixel_uv(AVFrame *frame, int hsub_log2, int vsub_log2, int x, int y, uint8_t *u, uint8_t *v)
65{
66 if (x < 0 || x >= frame->width || y < 0 || y >= frame->height)
67 return;
68
69 x >>= hsub_log2;
70 y >>= vsub_log2;
71
72 *u = frame->data[1][frame->linesize[1] * y + x];
73 *v = frame->data[2][frame->linesize[2] * y + x];
74}
75
76static int do_chromakey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
77{
78 AVFrame *frame = arg;
79
80 const int slice_start = (frame->height * jobnr) / nb_jobs;
81 const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
82
83 ChromakeyContext *ctx = avctx->priv;
84
85 int x, y, xo, yo;
86 uint8_t u[9], v[9];
87
88 memset(u, ctx->chromakey_uv[0], sizeof(u));
89 memset(v, ctx->chromakey_uv[1], sizeof(v));
90
91 for (y = slice_start; y < slice_end; ++y) {
92 for (x = 0; x < frame->width; ++x) {
93 for (yo = 0; yo < 3; ++yo) {
94 for (xo = 0; xo < 3; ++xo) {
95 get_pixel_uv(frame, ctx->hsub_log2, ctx->vsub_log2, x + xo - 1, y + yo - 1, &u[yo * 3 + xo], &v[yo * 3 + xo]);
96 }
97 }
98
99 frame->data[3][frame->linesize[3] * y + x] = do_chromakey_pixel(ctx, u, v);
100 }
101 }
102
103 return 0;
104}
105
106static int filter_frame(AVFilterLink *link, AVFrame *frame)
107{
108 AVFilterContext *avctx = link->dst;
109 int res;
110
111 if (res = avctx->internal->execute(avctx, do_chromakey_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(avctx))))
112 return res;
113
114 return ff_filter_frame(avctx->outputs[0], frame);
115}
116
117#define FIXNUM(x) lrint((x) * (1 << 10))
118#define RGB_TO_U(rgb) (((- FIXNUM(0.16874) * rgb[0] - FIXNUM(0.33126) * rgb[1] + FIXNUM(0.50000) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
119#define RGB_TO_V(rgb) ((( FIXNUM(0.50000) * rgb[0] - FIXNUM(0.41869) * rgb[1] - FIXNUM(0.08131) * rgb[2] + (1 << 9) - 1) >> 10) + 128)
120
121static av_cold int initialize_chromakey(AVFilterContext *avctx)
122{
123 ChromakeyContext *ctx = avctx->priv;
124
125 if (ctx->is_yuv) {
126 ctx->chromakey_uv[0] = ctx->chromakey_rgba[1];
127 ctx->chromakey_uv[1] = ctx->chromakey_rgba[2];
128 } else {
129 ctx->chromakey_uv[0] = RGB_TO_U(ctx->chromakey_rgba);
130 ctx->chromakey_uv[1] = RGB_TO_V(ctx->chromakey_rgba);
131 }
132
133 return 0;
134}
135
136static av_cold int query_formats(AVFilterContext *avctx)
137{
138 static const enum AVPixelFormat pixel_fmts[] = {
139 AV_PIX_FMT_YUVA420P,
140 AV_PIX_FMT_YUVA422P,
141 AV_PIX_FMT_YUVA444P,
142 AV_PIX_FMT_NONE
143 };
144
145 AVFilterFormats *formats = NULL;
146
147 formats = ff_make_format_list(pixel_fmts);
148 if (!formats)
149 return AVERROR(ENOMEM);
150
151 return ff_set_common_formats(avctx, formats);
152}
153
154static av_cold int config_input(AVFilterLink *inlink)
155{
156 AVFilterContext *avctx = inlink->dst;
157 ChromakeyContext *ctx = avctx->priv;
158 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
159
160 ctx->hsub_log2 = desc->log2_chroma_w;
161 ctx->vsub_log2 = desc->log2_chroma_h;
162
163 return 0;
164}
165
166static const AVFilterPad chromakey_inputs[] = {
167 {
168 .name = "default",
169 .type = AVMEDIA_TYPE_VIDEO,
170 .needs_writable = 1,
171 .filter_frame = filter_frame,
172 .config_props = config_input,
173 },
174 { NULL }
175};
176
177static const AVFilterPad chromakey_outputs[] = {
178 {
179 .name = "default",
180 .type = AVMEDIA_TYPE_VIDEO,
181 },
182 { NULL }
183};
184
185#define OFFSET(x) offsetof(ChromakeyContext, x)
186#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
187
188static const AVOption chromakey_options[] = {
189 { "color", "set the chromakey key color", OFFSET(chromakey_rgba), AV_OPT_TYPE_COLOR, { .str = "black" }, CHAR_MIN, CHAR_MAX, FLAGS },
190 { "similarity", "set the chromakey similarity value", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.01 }, 0.01, 1.0, FLAGS },
191 { "blend", "set the chromakey key blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
192 { "yuv", "color parameter is in yuv instead of rgb", OFFSET(is_yuv), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, FLAGS },
193 { NULL }
194};
195
196AVFILTER_DEFINE_CLASS(chromakey);
197
198AVFilter ff_vf_chromakey = {
199 .name = "chromakey",
200 .description = NULL_IF_CONFIG_SMALL("Turns a certain color into transparency. Operates on YUV colors."),
201 .priv_size = sizeof(ChromakeyContext),
202 .priv_class = &chromakey_class,
203 .init = initialize_chromakey,
204 .query_formats = query_formats,
205 .inputs = chromakey_inputs,
206 .outputs = chromakey_outputs,
207 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
208};
209
generated by cgit at 2024-05-17 03:39:32 (GMT)