FFmpeg
vf_grayworld.c
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1 /*
2  * Copyright (c) 2021 Paul Buxton
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  /**
22  * @file
23  * Color correction filter based on
24  * https://www.researchgate.net/publication/275213614_A_New_Color_Correction_Method_for_Underwater_Imaging
25  *
26  */
27 
28 #include "libavutil/imgutils.h"
29 #include "libavutil/opt.h"
30 #include "libavutil/pixdesc.h"
31 
32 #include "avfilter.h"
33 #include "formats.h"
34 #include "internal.h"
35 #include "video.h"
36 
37 typedef struct ThreadData {
38  AVFrame *in, *out;
39  float l_avg;
40  float a_avg;
41  float b_avg;
42 } ThreadData;
43 
44 typedef struct GrayWorldContext {
45  const AVClass *class;
46  float *tmpplab;
48  float *line_sum;
50 
51 #define OFFSET(x) offsetof(GrayWorldContext, x)
52 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM | AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_RUNTIME_PARAM
53 static const AVOption grayworld_options[] = {
54  { NULL }
55 };
56 
57 AVFILTER_DEFINE_CLASS(grayworld);
58 
59 static void apply_matrix(const float matrix[3][3], const float input[3], float output[3])
60 {
61  output[0] = matrix[0][0] * input[0] + matrix[0][1] * input[1] + matrix[0][2] * input[2];
62  output[1] = matrix[1][0] * input[0] + matrix[1][1] * input[1] + matrix[1][2] * input[2];
63  output[2] = matrix[2][0] * input[0] + matrix[2][1] * input[1] + matrix[2][2] * input[2];
64 }
65 
66 static const float lms2lab[3][3] = {
67  {0.5774, 0.5774, 0.5774},
68  {0.40825, 0.40825, -0.816458},
69  {0.707, -0.707, 0}
70 };
71 
72 static const float lab2lms[3][3] = {
73  {0.57735, 0.40825, 0.707},
74  {0.57735, 0.40825, -0.707},
75  {0.57735, -0.8165, 0}
76 };
77 
78 static const float rgb2lms[3][3] = {
79  {0.3811, 0.5783, 0.0402},
80  {0.1967, 0.7244, 0.0782},
81  {0.0241, 0.1288, 0.8444}
82 };
83 
84 static const float lms2rgb[3][3] = {
85  {4.4679, -3.5873, 0.1193},
86  {-1.2186, 2.3809, -0.1624},
87  {0.0497, -0.2439, 1.2045}
88 };
89 
90 /**
91  * Convert from Linear RGB to logspace LAB
92  *
93  * @param rgb Input array of rgb components
94  * @param lab output array of lab components
95  */
96 static void rgb2lab(const float rgb[3], float lab[3])
97 {
98  float lms[3];
99 
100  apply_matrix(rgb2lms, rgb, lms);
101  lms[0] = lms[0] > 0.f ? logf(lms[0]) : -1024.f;
102  lms[1] = lms[1] > 0.f ? logf(lms[1]) : -1024.f;
103  lms[2] = lms[2] > 0.f ? logf(lms[2]) : -1024.f;
104  apply_matrix(lms2lab, lms, lab);
105 }
106 
107 /**
108  * Convert from Logspace LAB to Linear RGB
109  *
110  * @param lab input array of lab components
111  * @param rgb output array of rgb components
112  */
113 static void lab2rgb(const float lab[3], float rgb[3])
114 {
115  float lms[3];
116 
117  apply_matrix(lab2lms, lab, lms);
118  lms[0] = expf(lms[0]);
119  lms[1] = expf(lms[1]);
120  lms[2] = expf(lms[2]);
121  apply_matrix(lms2rgb, lms, rgb);
122 }
123 
124 /**
125  * Convert a frame from linear RGB to logspace LAB, and accumulate channel totals for each row
126  * Convert from RGB -> lms using equation 4 in color transfer paper.
127  *
128  * @param ctx Filter context
129  * @param arg Thread data pointer
130  * @param jobnr job number
131  * @param nb_jobs number of jobs
132  */
133 static int convert_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
134 {
135  GrayWorldContext *s = ctx->priv;
136  ThreadData *td = arg;
137  AVFrame *in = td->in;
138  AVFrame *out = td->out;
139  AVFilterLink *outlink = ctx->outputs[0];
140  const int slice_start = (out->height * jobnr) / nb_jobs;
141  const int slice_end = (out->height * (jobnr + 1)) / nb_jobs;
142  float rgb[3], lab[3];
143 
144  for (int i = slice_start; i < slice_end; i++) {
145  float *b_in_row = (float *)(in->data[1] + i * in->linesize[1]);
146  float *g_in_row = (float *)(in->data[0] + i * in->linesize[0]);
147  float *r_in_row = (float *)(in->data[2] + i * in->linesize[2]);
148  float *acur = s->tmpplab + i * outlink->w + outlink->w * outlink->h;
149  float *bcur = s->tmpplab + i * outlink->w + 2 * outlink->w * outlink->h;
150  float *lcur = s->tmpplab + i * outlink->w;
151 
152  s->line_sum[i] = 0.f;
153  s->line_sum[i + outlink->h] = 0.f;
154  s->line_count_pels[i] = 0;
155 
156  for (int j = 0; j < outlink->w; j++) {
157  rgb[0] = r_in_row[j];
158  rgb[1] = g_in_row[j];
159  rgb[2] = b_in_row[j];
160  rgb2lab(rgb, lab);
161  *(lcur++) = lab[0];
162  *(acur++) = lab[1];
163  *(bcur++) = lab[2];
164  s->line_sum[i] += lab[1];
165  s->line_sum[i + outlink->h] += lab[2];
166  s->line_count_pels[i]++;
167  }
168  }
169  return 0;
170 }
171 
172 /**
173  * Sum the channel totals and compute the mean for each channel
174  *
175  * @param s Frame context
176  * @param td thread data
177  */
179 {
180  float asum = 0.f, bsum = 0.f;
181  int pixels = 0;
182 
183  for (int y = 0; y < td->out->height; y++) {
184  asum += s->line_sum[y];
185  bsum += s->line_sum[y + td->out->height];
186  pixels += s->line_count_pels[y];
187  }
188 
189  td->a_avg = asum / pixels;
190  td->b_avg = bsum / pixels;
191 }
192 
193 /**
194  * Subtract the mean logspace AB values from each pixel.
195  *
196  * @param ctx Filter context
197  * @param arg Thread data pointer
198  * @param jobnr job number
199  * @param nb_jobs number of jobs
200  */
201 static int correct_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
202 {
203  GrayWorldContext *s = ctx->priv;
204  ThreadData *td = arg;
205  AVFrame *out = td->out;
206  AVFilterLink *outlink = ctx->outputs[0];
207  const int slice_start = (out->height * jobnr) / nb_jobs;
208  const int slice_end = (out->height * (jobnr + 1)) / nb_jobs;
209  float rgb[3], lab[3];
210 
211  for (int i = slice_start; i < slice_end; i++) {
212  float *g_out_row = (float *)(out->data[0] + i * out->linesize[0]);
213  float *b_out_row = (float *)(out->data[1] + i * out->linesize[1]);
214  float *r_out_row = (float *)(out->data[2] + i * out->linesize[2]);
215  float *lcur = s->tmpplab + i * outlink->w;
216  float *acur = s->tmpplab + i * outlink->w + outlink->w * outlink->h;
217  float *bcur = s->tmpplab + i * outlink->w + 2 * outlink->w * outlink->h;
218 
219  for (int j = 0; j < outlink->w; j++) {
220  lab[0] = *lcur++;
221  lab[1] = *acur++;
222  lab[2] = *bcur++;
223 
224  // subtract the average for the color channels
225  lab[1] -= td->a_avg;
226  lab[2] -= td->b_avg;
227 
228  //convert back to linear rgb
229  lab2rgb(lab, rgb);
230  r_out_row[j] = rgb[0];
231  g_out_row[j] = rgb[1];
232  b_out_row[j] = rgb[2];
233  }
234  }
235  return 0;
236 }
237 
239 {
240  GrayWorldContext *s = inlink->dst->priv;
241 
242  FF_ALLOC_TYPED_ARRAY(s->tmpplab, inlink->h * inlink->w * 3);
243  FF_ALLOC_TYPED_ARRAY(s->line_count_pels, inlink->h);
244  FF_ALLOC_TYPED_ARRAY(s->line_sum, inlink->h * 2);
245  if (!s->tmpplab || !s->line_count_pels || !s->line_sum)
246  return AVERROR(ENOMEM);
247 
248  return 0;
249 }
250 
252 {
253  GrayWorldContext *s = ctx->priv;
254 
255  av_freep(&s->tmpplab);
256  av_freep(&s->line_count_pels);
257  av_freep(&s->line_sum);
258 }
259 
261 {
262  AVFilterContext *ctx = inlink->dst;
263  GrayWorldContext *s = ctx->priv;
264  AVFilterLink *outlink = ctx->outputs[0];
265  ThreadData td;
266  AVFrame *out;
267 
268  if (av_frame_is_writable(in)) {
269  out = in;
270  } else {
271  out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
272  if (!out) {
273  av_frame_free(&in);
274  return AVERROR(ENOMEM);
275  }
277  }
278  /* input and output transfer will be linear */
279  if (in->color_trc == AVCOL_TRC_UNSPECIFIED) {
280  av_log(s, AV_LOG_WARNING, "Untagged transfer, assuming linear light.\n");
281  out->color_trc = AVCOL_TRC_LINEAR;
282  } else if (in->color_trc != AVCOL_TRC_LINEAR) {
283  av_log(s, AV_LOG_WARNING, "Gray world color correction works on linear light only.\n");
284  }
285 
286  td.in = in;
287  td.out = out;
288 
292 
293  if (in != out) {
294  av_image_copy_plane(out->data[3], out->linesize[3],
295  in->data[3], in->linesize[3], outlink->w * 4, outlink->h);
296  av_frame_free(&in);
297  }
298 
299  return ff_filter_frame(outlink, out);
300 }
301 
302 static const AVFilterPad grayworld_inputs[] = {
303  {
304  .name = "default",
305  .type = AVMEDIA_TYPE_VIDEO,
306  .filter_frame = filter_frame,
307  .config_props = config_input,
308  }
309 };
310 
311 static const AVFilterPad grayworld_outputs[] = {
312  {
313  .name = "default",
314  .type = AVMEDIA_TYPE_VIDEO,
315  }
316 };
317 
319  .name = "grayworld",
320  .description = NULL_IF_CONFIG_SMALL("Adjust white balance using LAB gray world algorithm"),
321  .priv_size = sizeof(GrayWorldContext),
322  .priv_class = &grayworld_class,
327  .uninit = uninit,
328 };
ff_get_video_buffer
AVFrame * ff_get_video_buffer(AVFilterLink *link, int w, int h)
Request a picture buffer with a specific set of permissions.
Definition: video.c:98
AVFrame::color_trc
enum AVColorTransferCharacteristic color_trc
Definition: frame.h:534
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
td
#define td
Definition: regdef.h:70
convert_frame
static int convert_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Convert a frame from linear RGB to logspace LAB, and accumulate channel totals for each row Convert f...
Definition: vf_grayworld.c:133
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
opt.h
out
FILE * out
Definition: movenc.c:54
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1018
AVCOL_TRC_LINEAR
@ AVCOL_TRC_LINEAR
"Linear transfer characteristics"
Definition: pixfmt.h:485
output
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce output
Definition: filter_design.txt:225
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:112
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
pixdesc.h
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: vf_grayworld.c:251
AVOption
AVOption.
Definition: opt.h:247
AVCOL_TRC_UNSPECIFIED
@ AVCOL_TRC_UNSPECIFIED
Definition: pixfmt.h:479
expf
#define expf(x)
Definition: libm.h:283
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: vf_grayworld.c:260
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:153
grayworld_outputs
static const AVFilterPad grayworld_outputs[]
Definition: vf_grayworld.c:311
ThreadData::out
AVFrame * out
Definition: af_adeclick.c:473
video.h
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:317
av_image_copy_plane
void av_image_copy_plane(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize, int bytewidth, int height)
Copy image plane from src to dst.
Definition: imgutils.c:374
formats.h
rgb
Definition: rpzaenc.c:59
FF_ALLOC_TYPED_ARRAY
#define FF_ALLOC_TYPED_ARRAY(p, nelem)
Definition: internal.h:97
compute_correction
static void compute_correction(GrayWorldContext *s, ThreadData *td)
Sum the channel totals and compute the mean for each channel.
Definition: vf_grayworld.c:178
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:50
lms2rgb
static const float lms2rgb[3][3]
Definition: vf_grayworld.c:84
av_cold
#define av_cold
Definition: attributes.h:90
GrayWorldContext::line_sum
float * line_sum
Definition: vf_grayworld.c:48
s
#define s(width, name)
Definition: cbs_vp9.c:257
slice_end
static int slice_end(AVCodecContext *avctx, AVFrame *pict)
Handle slice ends.
Definition: mpeg12dec.c:2041
ctx
AVFormatContext * ctx
Definition: movenc.c:48
lab2rgb
static void lab2rgb(const float lab[3], float rgb[3])
Convert from Logspace LAB to Linear RGB.
Definition: vf_grayworld.c:113
apply_matrix
static void apply_matrix(const float matrix[3][3], const float input[3], float output[3])
Definition: vf_grayworld.c:59
ThreadData::b_avg
float b_avg
Definition: vf_grayworld.c:41
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: internal.h:191
arg
const char * arg
Definition: jacosubdec.c:67
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
av_frame_copy_props
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:537
ThreadData::a_avg
float a_avg
Definition: vf_grayworld.c:40
ff_vf_grayworld
const AVFilter ff_vf_grayworld
Definition: vf_grayworld.c:318
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
config_input
static int config_input(AVFilterLink *inlink)
Definition: vf_grayworld.c:238
FILTER_PIXFMTS
#define FILTER_PIXFMTS(...)
Definition: internal.h:177
AV_PIX_FMT_GBRPF32
#define AV_PIX_FMT_GBRPF32
Definition: pixfmt.h:420
av_frame_is_writable
int av_frame_is_writable(AVFrame *frame)
Check if the frame data is writable.
Definition: frame.c:473
GrayWorldContext
Definition: vf_grayworld.c:44
input
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some input
Definition: filter_design.txt:172
internal.h
AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
#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:130
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(grayworld)
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
ff_filter_get_nb_threads
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:803
ThreadData
Used for passing data between threads.
Definition: dsddec.c:67
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:56
AVFilter
Filter definition.
Definition: avfilter.h:149
rgb2lms
static const float rgb2lms[3][3]
Definition: vf_grayworld.c:78
rgb2lab
static void rgb2lab(const float rgb[3], float lab[3])
Convert from Linear RGB to logspace LAB.
Definition: vf_grayworld.c:96
lms2lab
static const float lms2lab[3][3]
Definition: vf_grayworld.c:66
avfilter.h
AV_PIX_FMT_GBRAPF32
#define AV_PIX_FMT_GBRAPF32
Definition: pixfmt.h:421
AVFilterContext
An instance of a filter.
Definition: avfilter.h:386
AVFILTER_FLAG_SLICE_THREADS
#define AVFILTER_FLAG_SLICE_THREADS
The filter supports multithreading by splitting frames into multiple parts and processing them concur...
Definition: avfilter.h:121
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
ThreadData::in
AVFrame * in
Definition: af_adecorrelate.c:154
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: internal.h:192
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:35
ThreadData::l_avg
float l_avg
Definition: vf_grayworld.c:39
GrayWorldContext::tmpplab
float * tmpplab
Definition: vf_grayworld.c:46
imgutils.h
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:334
lab2lms
static const float lab2lms[3][3]
Definition: vf_grayworld.c:72
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
correct_frame
static int correct_frame(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Subtract the mean logspace AB values from each pixel.
Definition: vf_grayworld.c:201
ff_filter_execute
static av_always_inline int ff_filter_execute(AVFilterContext *ctx, avfilter_action_func *func, void *arg, int *ret, int nb_jobs)
Definition: internal.h:143
grayworld_inputs
static const AVFilterPad grayworld_inputs[]
Definition: vf_grayworld.c:302
grayworld_options
static const AVOption grayworld_options[]
Definition: vf_grayworld.c:53
GrayWorldContext::line_count_pels
int * line_count_pels
Definition: vf_grayworld.c:47