1 /*
2 * Copyright (c) 2017 Paul B Mahol
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
28 typedef struct LumakeyContext {
29 const AVClass *class;
30
31 double threshold;
32 double tolerance;
33 double softness;
34
35 int white;
36 int black;
37 int so;
38 int max;
39
40 int (*do_lumakey_slice)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
41 } LumakeyContext;
42
do_lumakey_slice8(AVFilterContext * ctx,void * arg,int jobnr,int nb_jobs)43 static int do_lumakey_slice8(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
44 {
45 LumakeyContext *s = ctx->priv;
46 AVFrame *frame = arg;
47 const int slice_start = (frame->height * jobnr) / nb_jobs;
48 const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
49 uint8_t *alpha = frame->data[3] + slice_start * frame->linesize[3];
50 const uint8_t *luma = frame->data[0] + slice_start * frame->linesize[0];
51 const int so = s->so;
52 const int w = s->white;
53 const int b = s->black;
54 int x, y;
55
56 for (y = slice_start; y < slice_end; y++) {
57 for (x = 0; x < frame->width; x++) {
58 if (luma[x] >= b && luma[x] <= w) {
59 alpha[x] = 0;
60 } else if (luma[x] > b - so && luma[x] < w + so) {
61 if (luma[x] < b) {
62 alpha[x] = 255 - (luma[x] - b + so) * 255 / so;
63 } else {
64 alpha[x] = (luma[x] - w) * 255 / so;
65 }
66 }
67 }
68 luma += frame->linesize[0];
69 alpha += frame->linesize[3];
70 }
71
72 return 0;
73 }
74
do_lumakey_slice16(AVFilterContext * ctx,void * arg,int jobnr,int nb_jobs)75 static int do_lumakey_slice16(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
76 {
77 LumakeyContext *s = ctx->priv;
78 AVFrame *frame = arg;
79 const int slice_start = (frame->height * jobnr) / nb_jobs;
80 const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
81 uint16_t *alpha = (uint16_t *)(frame->data[3] + slice_start * frame->linesize[3]);
82 const uint16_t *luma = (const uint16_t *)(frame->data[0] + slice_start * frame->linesize[0]);
83 const int so = s->so;
84 const int w = s->white;
85 const int b = s->black;
86 const int m = s->max;
87 int x, y;
88
89 for (y = slice_start; y < slice_end; y++) {
90 for (x = 0; x < frame->width; x++) {
91 if (luma[x] >= b && luma[x] <= w) {
92 alpha[x] = 0;
93 } else if (luma[x] > b - so && luma[x] < w + so) {
94 if (luma[x] < b) {
95 alpha[x] = m - (luma[x] - b + so) * m / so;
96 } else {
97 alpha[x] = (luma[x] - w) * m / so;
98 }
99 }
100 }
101 luma += frame->linesize[0] / 2;
102 alpha += frame->linesize[3] / 2;
103 }
104
105 return 0;
106 }
107
config_input(AVFilterLink * inlink)108 static int config_input(AVFilterLink *inlink)
109 {
110 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
111 AVFilterContext *ctx = inlink->dst;
112 LumakeyContext *s = ctx->priv;
113 int depth;
114
115 depth = desc->comp[0].depth;
116 if (depth == 8) {
117 s->white = av_clip_uint8((s->threshold + s->tolerance) * 255);
118 s->black = av_clip_uint8((s->threshold - s->tolerance) * 255);
119 s->do_lumakey_slice = do_lumakey_slice8;
120 s->so = s->softness * 255;
121 } else {
122 s->max = (1 << depth) - 1;
123 s->white = av_clip((s->threshold + s->tolerance) * s->max, 0, s->max);
124 s->black = av_clip((s->threshold - s->tolerance) * s->max, 0, s->max);
125 s->do_lumakey_slice = do_lumakey_slice16;
126 s->so = s->softness * s->max;
127 }
128
129 return 0;
130 }
131
filter_frame(AVFilterLink * link,AVFrame * frame)132 static int filter_frame(AVFilterLink *link, AVFrame *frame)
133 {
134 AVFilterContext *ctx = link->dst;
135 LumakeyContext *s = ctx->priv;
136 int ret;
137
138 if (ret = ff_filter_execute(ctx, s->do_lumakey_slice, frame, NULL,
139 FFMIN(frame->height, ff_filter_get_nb_threads(ctx))))
140 return ret;
141
142 return ff_filter_frame(ctx->outputs[0], frame);
143 }
144
145 static const enum AVPixelFormat pixel_fmts[] = {
146 AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
147 AV_PIX_FMT_YUVA444P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA420P9,
148 AV_PIX_FMT_YUVA444P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA420P10,
149 AV_PIX_FMT_YUVA444P12, AV_PIX_FMT_YUVA422P12,
150 AV_PIX_FMT_YUVA444P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA420P16,
151 AV_PIX_FMT_NONE
152 };
153
process_command(AVFilterContext * ctx,const char * cmd,const char * args,char * res,int res_len,int flags)154 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
155 char *res, int res_len, int flags)
156 {
157 int ret;
158
159 ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
160 if (ret < 0)
161 return ret;
162
163 return config_input(ctx->inputs[0]);
164 }
165
166 static const AVFilterPad lumakey_inputs[] = {
167 {
168 .name = "default",
169 .type = AVMEDIA_TYPE_VIDEO,
170 .flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
171 .filter_frame = filter_frame,
172 .config_props = config_input,
173 },
174 };
175
176 static const AVFilterPad lumakey_outputs[] = {
177 {
178 .name = "default",
179 .type = AVMEDIA_TYPE_VIDEO,
180 },
181 };
182
183 #define OFFSET(x) offsetof(LumakeyContext, x)
184 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
185
186 static const AVOption lumakey_options[] = {
187 { "threshold", "set the threshold value", OFFSET(threshold), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, FLAGS },
188 { "tolerance", "set the tolerance value", OFFSET(tolerance), AV_OPT_TYPE_DOUBLE, {.dbl=0.01}, 0, 1, FLAGS },
189 { "softness", "set the softness value", OFFSET(softness), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, FLAGS },
190 { NULL }
191 };
192
193 AVFILTER_DEFINE_CLASS(lumakey);
194
195 const AVFilter ff_vf_lumakey = {
196 .name = "lumakey",
197 .description = NULL_IF_CONFIG_SMALL("Turns a certain luma into transparency."),
198 .priv_size = sizeof(LumakeyContext),
199 .priv_class = &lumakey_class,
200 FILTER_INPUTS(lumakey_inputs),
201 FILTER_OUTPUTS(lumakey_outputs),
202 FILTER_PIXFMTS_ARRAY(pixel_fmts),
203 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
204 .process_command = process_command,
205 };
206