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vf_chromakey.c
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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 
28 typedef struct ChromakeyContext {
29  const AVClass *class;
30 
33 
34  float similarity;
35  float blend;
36 
37  int is_yuv;
38 
39  int hsub_log2;
40  int vsub_log2;
42 
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 
64 static 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 
76 static 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 
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 
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 
137 {
138  static const enum AVPixelFormat pixel_fmts[] = {
143  };
144 
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 
154 static av_cold int config_input(AVFilterLink *inlink)
155 {
156  AVFilterContext *avctx = inlink->dst;
157  ChromakeyContext *ctx = avctx->priv;
159 
160  ctx->hsub_log2 = desc->log2_chroma_w;
161  ctx->vsub_log2 = desc->log2_chroma_h;
162 
163  return 0;
164 }
165 
166 static 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 
177 static 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 
188 static 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 
196 AVFILTER_DEFINE_CLASS(chromakey);
197 
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,
205  .inputs = chromakey_inputs,
206  .outputs = chromakey_outputs,
208 };
#define NULL
Definition: coverity.c:32
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:2406
This structure describes decoded (raw) audio or video data.
Definition: frame.h:218
AVOption.
Definition: opt.h:246
misc image utilities
Main libavfilter public API header.
const char * desc
Definition: nvenc.c:65
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
AVFILTER_DEFINE_CLASS(chromakey)
uint8_t log2_chroma_w
Amount to shift the luma width right to find the chroma width.
Definition: pixdesc.h:92
AVFilterFormats * ff_make_format_list(const int *fmts)
Create a list of supported formats.
Definition: formats.c:283
#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
Some filters support a generic "enable" expression option that can be used to enable or disable a fil...
Definition: avfilter.h:125
const char * name
Pad name.
Definition: internal.h:60
uint8_t chromakey_uv[2]
Definition: vf_chromakey.c:32
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1080
planar YUV 4:2:0, 20bpp, (1 Cr & Cb sample per 2x2 Y & A samples)
Definition: pixfmt.h:101
uint8_t
#define av_cold
Definition: attributes.h:82
AVOptions.
static const AVFilterPad chromakey_outputs[]
Definition: vf_chromakey.c:177
#define u(width, name, range_min, range_max)
Definition: cbs_h2645.c:253
static AVFrame * frame
#define flags(name, subs,...)
Definition: cbs_h2645.c:263
static av_cold int initialize_chromakey(AVFilterContext *avctx)
Definition: vf_chromakey.c:121
A filter pad used for either input or output.
Definition: internal.h:54
static const AVOption chromakey_options[]
Definition: vf_chromakey.c:188
planar YUV 4:2:2 24bpp, (1 Cr & Cb sample per 2x1 Y & A samples)
Definition: pixfmt.h:176
int width
Definition: frame.h:276
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:568
uint8_t log2_chroma_h
Amount to shift the luma height right to find the chroma height.
Definition: pixdesc.h:101
static uint8_t do_chromakey_pixel(ChromakeyContext *ctx, uint8_t u[9], uint8_t v[9])
Definition: vf_chromakey.c:43
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
void * priv
private data for use by the filter
Definition: avfilter.h:353
#define AVFILTER_FLAG_SLICE_THREADS
The filter supports multithreading by splitting frames into multiple parts and processing them concur...
Definition: avfilter.h:116
const char * arg
Definition: jacosubdec.c:66
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:802
#define FFMIN(a, b)
Definition: common.h:96
AVFilter ff_vf_chromakey
Definition: vf_chromakey.c:198
uint8_t chromakey_rgba[4]
Definition: vf_chromakey.c:31
AVFormatContext * ctx
Definition: movenc.c:48
static int filter_frame(AVFilterLink *link, AVFrame *frame)
Definition: vf_chromakey.c:106
static const AVFilterPad inputs[]
Definition: af_acontrast.c:193
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:249
planar YUV 4:4:4 32bpp, (1 Cr & Cb sample per 1x1 Y & A samples)
Definition: pixfmt.h:177
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:81
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
#define OFFSET(x)
Definition: vf_chromakey.c:185
const char * name
Filter name.
Definition: avfilter.h:148
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:350
#define RGB_TO_U(rgb)
Definition: vf_chromakey.c:118
AVFilterInternal * internal
An opaque struct for libavfilter internal use.
Definition: avfilter.h:378
#define FLAGS
Definition: vf_chromakey.c:186
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:232
static av_cold int query_formats(AVFilterContext *avctx)
Definition: vf_chromakey.c:136
static const AVFilterPad chromakey_inputs[]
Definition: vf_chromakey.c:166
static 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)
Definition: vf_chromakey.c:64
int
avfilter_execute_func * execute
Definition: internal.h:155
static av_cold int config_input(AVFilterLink *inlink)
Definition: vf_chromakey.c:154
static int do_chromakey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
Definition: vf_chromakey.c:76
static int slice_end(AVCodecContext *avctx, AVFrame *pict)
Handle slice ends.
Definition: mpeg12dec.c:2029
#define RGB_TO_V(rgb)
Definition: vf_chromakey.c:119
static av_always_inline int diff(const uint32_t a, const uint32_t b)
A list of supported formats for one end of a filter link.
Definition: formats.h:64
An instance of a filter.
Definition: avfilter.h:338
int height
Definition: frame.h:276
#define av_always_inline
Definition: attributes.h:39
formats
Definition: signature.h:48
internal API functions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64