FFmpeg
vf_photosensitivity.c
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1 /*
2  * Copyright (c) 2019 Vladimir Panteleev
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 <float.h>
22 
23 #include "libavutil/opt.h"
24 #include "avfilter.h"
25 
26 #include "filters.h"
27 #include "video.h"
28 
29 #define MAX_FRAMES 240
30 #define GRID_SIZE 8
31 #define NUM_CHANNELS 3
32 
33 typedef struct PhotosensitivityFrame {
34  uint8_t grid[GRID_SIZE][GRID_SIZE][4];
36 
37 typedef struct PhotosensitivityContext {
38  const AVClass *class;
39 
40  int nb_frames;
41  int skip;
43  int bypass;
44 
46 
47  /* Circular buffer */
50 
54 
55 #define OFFSET(x) offsetof(PhotosensitivityContext, x)
56 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
57 
59  { "frames", "set how many frames to use", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
60  { "f", "set how many frames to use", OFFSET(nb_frames), AV_OPT_TYPE_INT, {.i64=30}, 2, MAX_FRAMES, FLAGS },
61  { "threshold", "set detection threshold factor (lower is stricter)", OFFSET(threshold_multiplier), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0.1, FLT_MAX, FLAGS },
62  { "t", "set detection threshold factor (lower is stricter)", OFFSET(threshold_multiplier), AV_OPT_TYPE_FLOAT, {.dbl=1}, 0.1, FLT_MAX, FLAGS },
63  { "skip", "set pixels to skip when sampling frames", OFFSET(skip), AV_OPT_TYPE_INT, {.i64=1}, 1, 1024, FLAGS },
64  { "bypass", "leave frames unchanged", OFFSET(bypass), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
65  { NULL }
66 };
67 
68 AVFILTER_DEFINE_CLASS(photosensitivity);
69 
71 {
74  int skip;
76 
77 #define NUM_CELLS (GRID_SIZE * GRID_SIZE)
78 
79 static int convert_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
80 {
81  int cell, gx, gy, x0, x1, y0, y1, x, y, c, area;
82  int sum[NUM_CHANNELS];
83  const uint8_t *p;
84 
86 
87  const int slice_start = (NUM_CELLS * jobnr) / nb_jobs;
88  const int slice_end = (NUM_CELLS * (jobnr+1)) / nb_jobs;
89 
90  int width = td->in->width, height = td->in->height, linesize = td->in->linesize[0], skip = td->skip;
91  const uint8_t *data = td->in->data[0];
92 
93  for (cell = slice_start; cell < slice_end; cell++) {
94  gx = cell % GRID_SIZE;
95  gy = cell / GRID_SIZE;
96 
97  x0 = width * gx / GRID_SIZE;
98  x1 = width * (gx+1) / GRID_SIZE;
99  y0 = height * gy / GRID_SIZE;
100  y1 = height * (gy+1) / GRID_SIZE;
101 
102  for (c = 0; c < NUM_CHANNELS; c++) {
103  sum[c] = 0;
104  }
105  for (y = y0; y < y1; y += skip) {
106  p = data + y * linesize + x0 * NUM_CHANNELS;
107  for (x = x0; x < x1; x += skip) {
108  //av_log(NULL, AV_LOG_VERBOSE, "%d %d %d : (%d,%d) (%d,%d) -> %d,%d | *%d\n", c, gx, gy, x0, y0, x1, y1, x, y, (int)row);
109  sum[0] += p[0];
110  sum[1] += p[1];
111  sum[2] += p[2];
112  p += NUM_CHANNELS * skip;
113  // TODO: variable size
114  }
115  }
116 
117  area = ((x1 - x0 + skip - 1) / skip) * ((y1 - y0 + skip - 1) / skip);
118  for (c = 0; c < NUM_CHANNELS; c++) {
119  if (area)
120  sum[c] /= area;
121  td->out->grid[gy][gx][c] = sum[c];
122  }
123  }
124  return 0;
125 }
126 
128 {
130  td.in = in;
131  td.out = out;
132  td.skip = skip;
135 }
136 
138 {
141  uint16_t s_mul;
143 
144 static int blend_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
145 {
146  int x, y;
147  uint8_t *t, *s;
148 
150  const uint16_t s_mul = td->s_mul;
151  const uint16_t t_mul = 0x100 - s_mul;
152  const int slice_start = (td->target->height * jobnr) / nb_jobs;
153  const int slice_end = (td->target->height * (jobnr+1)) / nb_jobs;
154  const int linesize = td->target->linesize[0];
155 
156  for (y = slice_start; y < slice_end; y++) {
157  t = td->target->data[0] + y * td->target->linesize[0];
158  s = td->source->data[0] + y * td->source->linesize[0];
159  for (x = 0; x < linesize; x++) {
160  *t = (*t * t_mul + *s * s_mul) >> 8;
161  t++; s++;
162  }
163  }
164  return 0;
165 }
166 
167 static void blend_frame(AVFilterContext *ctx, AVFrame *target, AVFrame *source, float factor)
168 {
170  td.target = target;
171  td.source = source;
172  td.s_mul = (uint16_t)(factor * 0x100);
174  FFMIN(ctx->outputs[0]->h, ff_filter_get_nb_threads(ctx)));
175 }
176 
178 {
179  int badness, x, y, c;
180  badness = 0;
181  for (c = 0; c < NUM_CHANNELS; c++) {
182  for (y = 0; y < GRID_SIZE; y++) {
183  for (x = 0; x < GRID_SIZE; x++) {
184  badness += abs((int)a->grid[y][x][c] - (int)b->grid[y][x][c]);
185  //av_log(NULL, AV_LOG_VERBOSE, "%d - %d -> %d \n", a->grid[y][x], b->grid[y][x], badness);
186  //av_log(NULL, AV_LOG_VERBOSE, "%d -> %d \n", abs((int)a->grid[y][x] - (int)b->grid[y][x]), badness);
187  }
188  }
189  }
190  return badness;
191 }
192 
194 {
195  /* const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format); */
196  AVFilterContext *ctx = inlink->dst;
197  PhotosensitivityContext *s = ctx->priv;
198 
199  s->badness_threshold = (int)(GRID_SIZE * GRID_SIZE * 4 * 256 * s->nb_frames * s->threshold_multiplier / 128);
200 
201  return 0;
202 }
203 
205 {
206  int this_badness, current_badness, fixed_badness, new_badness, i, res;
208  AVFrame *src, *out;
209  int free_in = 0;
210  float factor;
211  AVDictionary **metadata;
212 
213  AVFilterContext *ctx = inlink->dst;
214  AVFilterLink *outlink = ctx->outputs[0];
215  PhotosensitivityContext *s = ctx->priv;
216 
217  /* weighted moving average */
218  current_badness = 0;
219  for (i = 1; i < s->nb_frames; i++)
220  current_badness += i * s->history[(s->history_pos + i) % s->nb_frames];
221  current_badness /= s->nb_frames;
222 
223  convert_frame(ctx, in, &ef, s->skip);
224  this_badness = get_badness(&ef, &s->last_frame_e);
225  new_badness = current_badness + this_badness;
226  av_log(s, AV_LOG_VERBOSE, "badness: %6d -> %6d / %6d (%3d%% - %s)\n",
227  current_badness, new_badness, s->badness_threshold,
228  100 * new_badness / s->badness_threshold, new_badness < s->badness_threshold ? "OK" : "EXCEEDED");
229 
230  fixed_badness = new_badness;
231  if (new_badness < s->badness_threshold || !s->last_frame_av || s->bypass) {
232  factor = 1; /* for metadata */
233  av_frame_free(&s->last_frame_av);
234  s->last_frame_av = src = in;
235  s->last_frame_e = ef;
236  s->history[s->history_pos] = this_badness;
237  } else {
238  factor = (float)(s->badness_threshold - current_badness) / (new_badness - current_badness);
239  if (factor <= 0) {
240  /* just duplicate the frame */
241  s->history[s->history_pos] = 0; /* frame was duplicated, thus, delta is zero */
242  } else {
243  res = ff_inlink_make_frame_writable(inlink, &s->last_frame_av);
244  if (res) {
245  av_frame_free(&in);
246  return res;
247  }
248  blend_frame(ctx, s->last_frame_av, in, factor);
249 
250  convert_frame(ctx, s->last_frame_av, &ef, s->skip);
251  this_badness = get_badness(&ef, &s->last_frame_e);
252  fixed_badness = current_badness + this_badness;
253  av_log(s, AV_LOG_VERBOSE, " fixed: %6d -> %6d / %6d (%3d%%) factor=%5.3f\n",
254  current_badness, fixed_badness, s->badness_threshold,
255  100 * new_badness / s->badness_threshold, factor);
256  s->last_frame_e = ef;
257  s->history[s->history_pos] = this_badness;
258  }
259  src = s->last_frame_av;
260  free_in = 1;
261  }
262  s->history_pos = (s->history_pos + 1) % s->nb_frames;
263 
264  out = ff_get_video_buffer(outlink, in->width, in->height);
265  if (!out) {
266  if (free_in == 1)
267  av_frame_free(&in);
268  return AVERROR(ENOMEM);
269  }
271  metadata = &out->metadata;
272  if (metadata) {
273  char value[128];
274 
275  snprintf(value, sizeof(value), "%f", (float)new_badness / s->badness_threshold);
276  av_dict_set(metadata, "lavfi.photosensitivity.badness", value, 0);
277 
278  snprintf(value, sizeof(value), "%f", (float)fixed_badness / s->badness_threshold);
279  av_dict_set(metadata, "lavfi.photosensitivity.fixed-badness", value, 0);
280 
281  snprintf(value, sizeof(value), "%f", (float)this_badness / s->badness_threshold);
282  av_dict_set(metadata, "lavfi.photosensitivity.frame-badness", value, 0);
283 
284  snprintf(value, sizeof(value), "%f", factor);
285  av_dict_set(metadata, "lavfi.photosensitivity.factor", value, 0);
286  }
288  if (free_in == 1)
289  av_frame_free(&in);
290  return ff_filter_frame(outlink, out);
291 }
292 
294 {
295  PhotosensitivityContext *s = ctx->priv;
296 
297  av_frame_free(&s->last_frame_av);
298 }
299 
300 static const AVFilterPad inputs[] = {
301  {
302  .name = "default",
303  .type = AVMEDIA_TYPE_VIDEO,
304  .filter_frame = filter_frame,
305  .config_props = config_input,
306  },
307 };
308 
310  .name = "photosensitivity",
311  .description = NULL_IF_CONFIG_SMALL("Filter out photosensitive epilepsy seizure-inducing flashes."),
312  .priv_size = sizeof(PhotosensitivityContext),
313  .priv_class = &photosensitivity_class,
314  .uninit = uninit,
318 };
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:116
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(photosensitivity)
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
config_input
static int config_input(AVFilterLink *inlink)
Definition: vf_photosensitivity.c:193
out
FILE * out
Definition: movenc.c:55
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1025
PhotosensitivityContext
Definition: vf_photosensitivity.c:37
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
PhotosensitivityContext::history
int history[MAX_FRAMES]
Definition: vf_photosensitivity.c:48
PhotosensitivityContext::badness_threshold
int badness_threshold
Definition: vf_photosensitivity.c:45
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:162
FILTER_INPUTS
#define FILTER_INPUTS(array)
Definition: filters.h:262
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:389
AVFrame::width
int width
Definition: frame.h:461
GRID_SIZE
#define GRID_SIZE
Definition: vf_photosensitivity.c:30
AVOption
AVOption.
Definition: opt.h:429
b
#define b
Definition: input.c:41
data
const char data[16]
Definition: mxf.c:148
AV_LOG_VERBOSE
#define AV_LOG_VERBOSE
Detailed information.
Definition: log.h:225
float.h
AV_PIX_FMT_BGR24
@ AV_PIX_FMT_BGR24
packed RGB 8:8:8, 24bpp, BGRBGR...
Definition: pixfmt.h:76
AVDictionary
Definition: dict.c:34
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:205
video.h
convert_frame_partial
static int convert_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Definition: vf_photosensitivity.c:79
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:410
ThreadData_blend_frame::target
AVFrame * target
Definition: vf_photosensitivity.c:139
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: vf_photosensitivity.c:293
slice_end
static int slice_end(AVCodecContext *avctx, AVFrame *pict, int *got_output)
Handle slice ends.
Definition: mpeg12dec.c:1719
photosensitivity_options
static const AVOption photosensitivity_options[]
Definition: vf_photosensitivity.c:58
PhotosensitivityContext::last_frame_e
PhotosensitivityFrame last_frame_e
Definition: vf_photosensitivity.c:51
PhotosensitivityContext::last_frame_av
AVFrame * last_frame_av
Definition: vf_photosensitivity.c:52
ThreadData_convert_frame::skip
int skip
Definition: vf_photosensitivity.c:74
ff_vf_photosensitivity
const AVFilter ff_vf_photosensitivity
Definition: vf_photosensitivity.c:309
AVFilterPad
A filter pad used for either input or output.
Definition: filters.h:38
av_cold
#define av_cold
Definition: attributes.h:90
ff_video_default_filterpad
const AVFilterPad ff_video_default_filterpad[1]
An AVFilterPad array whose only entry has name "default" and is of type AVMEDIA_TYPE_VIDEO.
Definition: video.c:37
float
float
Definition: af_crystalizer.c:122
s
#define s(width, name)
Definition: cbs_vp9.c:198
ThreadData_convert_frame
Definition: vf_photosensitivity.c:70
PhotosensitivityFrame::grid
uint8_t grid[GRID_SIZE][GRID_SIZE][4]
Definition: vf_photosensitivity.c:34
OFFSET
#define OFFSET(x)
Definition: vf_photosensitivity.c:55
filters.h
ctx
AVFormatContext * ctx
Definition: movenc.c:49
FILTER_OUTPUTS
#define FILTER_OUTPUTS(array)
Definition: filters.h:263
convert_frame
static void convert_frame(AVFilterContext *ctx, AVFrame *in, PhotosensitivityFrame *out, int skip)
Definition: vf_photosensitivity.c:127
ff_inlink_make_frame_writable
int ff_inlink_make_frame_writable(AVFilterLink *link, AVFrame **rframe)
Make sure a frame is writable.
Definition: avfilter.c:1500
arg
const char * arg
Definition: jacosubdec.c:67
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:75
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:713
FLAGS
#define FLAGS
Definition: vf_photosensitivity.c:56
ThreadData_convert_frame::out
PhotosensitivityFrame * out
Definition: vf_photosensitivity.c:73
PhotosensitivityFrame
Definition: vf_photosensitivity.c:33
abs
#define abs(x)
Definition: cuda_runtime.h:35
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
PhotosensitivityContext::history_pos
int history_pos
Definition: vf_photosensitivity.c:49
source
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a source
Definition: filter_design.txt:255
AV_PIX_FMT_RGB24
@ AV_PIX_FMT_RGB24
packed RGB 8:8:8, 24bpp, RGBRGB...
Definition: pixfmt.h:75
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:94
height
#define height
Definition: dsp.h:85
av_frame_copy
int av_frame_copy(AVFrame *dst, const AVFrame *src)
Copy the frame data from src to dst.
Definition: frame.c:1003
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: vf_photosensitivity.c:204
blend_frame
static void blend_frame(AVFilterContext *ctx, AVFrame *target, AVFrame *source, float factor)
Definition: vf_photosensitivity.c:167
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
AV_OPT_TYPE_FLOAT
@ AV_OPT_TYPE_FLOAT
Underlying C type is float.
Definition: opt.h:271
PhotosensitivityContext::skip
int skip
Definition: vf_photosensitivity.c:41
NUM_CHANNELS
#define NUM_CHANNELS
Definition: vf_photosensitivity.c:31
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
ff_filter_get_nb_threads
int ff_filter_get_nb_threads(AVFilterContext *ctx)
Get number of threads for current filter instance.
Definition: avfilter.c:836
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition: writing_filters.txt:86
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
ThreadData_blend_frame::s_mul
uint16_t s_mul
Definition: vf_photosensitivity.c:141
AVFilterPad::name
const char * name
Pad name.
Definition: filters.h:44
FILTER_PIXFMTS
#define FILTER_PIXFMTS(...)
Definition: filters.h:248
slice_start
static int slice_start(SliceContext *sc, VVCContext *s, VVCFrameContext *fc, const CodedBitstreamUnit *unit, const int is_first_slice)
Definition: dec.c:737
PhotosensitivityContext::bypass
int bypass
Definition: vf_photosensitivity.c:43
AVFilter
Filter definition.
Definition: avfilter.h:201
ThreadData_blend_frame
Definition: vf_photosensitivity.c:137
ThreadData_blend_frame::source
AVFrame * source
Definition: vf_photosensitivity.c:140
MAX_FRAMES
#define MAX_FRAMES
Definition: vf_photosensitivity.c:29
AVFrame::height
int height
Definition: frame.h:461
blend_frame_partial
static int blend_frame_partial(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
Definition: vf_photosensitivity.c:144
ff_filter_execute
int ff_filter_execute(AVFilterContext *ctx, avfilter_action_func *func, void *arg, int *ret, int nb_jobs)
Definition: avfilter.c:1653
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Underlying C type is int.
Definition: opt.h:259
avfilter.h
AVFilterContext
An instance of a filter.
Definition: avfilter.h:457
factor
static const int factor[16]
Definition: vf_pp7.c:80
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
inputs
static const AVFilterPad inputs[]
Definition: vf_photosensitivity.c:300
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Underlying C type is int.
Definition: opt.h:327
av_dict_set
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Definition: dict.c:88
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, a positive or negative value, which is typically indicating the size in bytes of each pict...
Definition: frame.h:434
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
PhotosensitivityContext::nb_frames
int nb_frames
Definition: vf_photosensitivity.c:40
get_badness
static int get_badness(PhotosensitivityFrame *a, PhotosensitivityFrame *b)
Definition: vf_photosensitivity.c:177
width
#define width
Definition: dsp.h:85
NUM_CELLS
#define NUM_CELLS
Definition: vf_photosensitivity.c:77
snprintf
#define snprintf
Definition: snprintf.h:34
PhotosensitivityContext::threshold_multiplier
float threshold_multiplier
Definition: vf_photosensitivity.c:42
skip
static void BS_FUNC() skip(BSCTX *bc, unsigned int n)
Skip n bits in the buffer.
Definition: bitstream_template.h:375
src
#define src
Definition: vp8dsp.c:248
ThreadData_convert_frame::in
AVFrame * in
Definition: vf_photosensitivity.c:72