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1 /*
2  * Copyright (c) 2017 Ronald S. Bultje <rsbultje@gmail.com>
3  * Copyright (c) 2017 Ashish Pratap Singh <ashk43712@gmail.com>
4  * Copyright (c) 2021 Paul B Mahol
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * Calculate VIF between two input videos.
26  */
27 
28 #include <float.h>
29 
30 #include "libavutil/avstring.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/pixdesc.h"
33 #include "avfilter.h"
34 #include "framesync.h"
35 #include "drawutils.h"
36 #include "formats.h"
37 #include "internal.h"
38 #include "vif.h"
39 #include "video.h"
40 
41 typedef struct VIFContext {
42     const AVClass *class;
43     FFFrameSync fs;
44     const AVPixFmtDescriptor *desc;
45     int width;
46     int height;
47     int nb_threads;
48     float factor;
49     float *data_buf[13];
50     float **temp;
51     float *ref_data;
52     float *main_data;
53     double vif_sum[4];
54     double vif_min[4];
55     double vif_max[4];
56     uint64_t nb_frames;
57 } VIFContext;
58 
59 #define OFFSET(x) offsetof(VIFContext, x)
60 
61 static const AVOption vif_options[] = {
62     { NULL }
63 };
64 
65 AVFILTER_DEFINE_CLASS(vif);
66 
67 static const uint8_t vif_filter1d_width1[4] = { 17, 9, 5, 3 };
68 
69 static const float vif_filter1d_table[4][17] =
70 {
71     {
72         0.00745626912, 0.0142655009, 0.0250313189, 0.0402820669, 0.0594526194,
73         0.0804751068, 0.0999041125, 0.113746084, 0.118773937, 0.113746084,
74         0.0999041125, 0.0804751068, 0.0594526194, 0.0402820669, 0.0250313189,
75         0.0142655009, 0.00745626912
76     },
77     {
78         0.0189780835, 0.0558981746, 0.120920904, 0.192116052, 0.224173605,
79         0.192116052, 0.120920904, 0.0558981746, 0.0189780835
80     },
81     {
82         0.054488685, 0.244201347, 0.402619958, 0.244201347, 0.054488685
83     },
84     {
85         0.166378498, 0.667243004, 0.166378498
86     }
87 };
88 
89 typedef struct ThreadData {
90     const float *filter;
91     const float *src;
92     float *dst;
93     int w, h;
94     int src_stride;
95     int dst_stride;
96     int filter_width;
97     float **temp;
98 } ThreadData;
99 
vif_dec2(const float * src,float * dst,int w,int h,int src_stride,int dst_stride)100 static void vif_dec2(const float *src, float *dst, int w, int h,
101                      int src_stride, int dst_stride)
102 {
103     const int dst_px_stride = dst_stride / 2;
104 
105     for (int i = 0; i < h / 2; i++) {
106         for (int j = 0; j < w / 2; j++)
107             dst[i * dst_px_stride + j] = src[(i * 2) * src_stride + (j * 2)];
108     }
109 }
110 
vif_statistic(const float * mu1_sq,const float * mu2_sq,const float * mu1_mu2,const float * xx_filt,const float * yy_filt,const float * xy_filt,float * num,float * den,int w,int h)111 static void vif_statistic(const float *mu1_sq, const float *mu2_sq,
112                           const float *mu1_mu2, const float *xx_filt,
113                           const float *yy_filt, const float *xy_filt,
114                           float *num, float *den, int w, int h)
115 {
116     static const float sigma_nsq = 2;
117     float mu1_sq_val, mu2_sq_val, mu1_mu2_val, xx_filt_val, yy_filt_val, xy_filt_val;
118     float sigma1_sq, sigma2_sq, sigma12, g, sv_sq, eps = 1.0e-10f;
119     float gain_limit = 100.f;
120     float num_val, den_val;
121     float accum_num = 0.0f;
122     float accum_den = 0.0f;
123 
124     for (int i = 0; i < h; i++) {
125         float accum_inner_num = 0.f;
126         float accum_inner_den = 0.f;
127 
128         for (int j = 0; j < w; j++) {
129             mu1_sq_val  = mu1_sq[i * w + j];
130             mu2_sq_val  = mu2_sq[i * w + j];
131             mu1_mu2_val = mu1_mu2[i * w + j];
132             xx_filt_val = xx_filt[i * w + j];
133             yy_filt_val = yy_filt[i * w + j];
134             xy_filt_val = xy_filt[i * w + j];
135 
136             sigma1_sq = xx_filt_val - mu1_sq_val;
137             sigma2_sq = yy_filt_val - mu2_sq_val;
138             sigma12   = xy_filt_val - mu1_mu2_val;
139 
140             sigma1_sq = FFMAX(sigma1_sq, 0.0f);
141             sigma2_sq = FFMAX(sigma2_sq, 0.0f);
142             sigma12   = FFMAX(sigma12,   0.0f);
143 
144             g = sigma12 / (sigma1_sq + eps);
145             sv_sq = sigma2_sq - g * sigma12;
146 
147             if (sigma1_sq < eps) {
148                 g = 0.0f;
149                 sv_sq = sigma2_sq;
150                 sigma1_sq = 0.0f;
151             }
152 
153             if (sigma2_sq < eps) {
154                 g = 0.0f;
155                 sv_sq = 0.0f;
156             }
157 
158             if (g < 0.0f) {
159                 sv_sq = sigma2_sq;
160                 g = 0.0f;
161             }
162             sv_sq = FFMAX(sv_sq, eps);
163 
164             g = FFMIN(g, gain_limit);
165 
166             num_val = log2f(1.0f + g * g * sigma1_sq / (sv_sq + sigma_nsq));
167             den_val = log2f(1.0f + sigma1_sq / sigma_nsq);
168 
169             if (isnan(den_val))
170                 num_val = den_val = 1.f;
171 
172             accum_inner_num += num_val;
173             accum_inner_den += den_val;
174         }
175 
176         accum_num += accum_inner_num;
177         accum_den += accum_inner_den;
178     }
179 
180     num[0] = accum_num;
181     den[0] = accum_den;
182 }
183 
vif_xx_yy_xy(const float * x,const float * y,float * xx,float * yy,float * xy,int w,int h)184 static void vif_xx_yy_xy(const float *x, const float *y, float *xx, float *yy,
185                          float *xy, int w, int h)
186 {
187     for (int i = 0; i < h; i++) {
188         for (int j = 0; j < w; j++) {
189             float xval = x[j];
190             float yval = y[j];
191             float xxval = xval * xval;
192             float yyval = yval * yval;
193             float xyval = xval * yval;
194 
195             xx[j] = xxval;
196             yy[j] = yyval;
197             xy[j] = xyval;
198         }
199 
200         xx += w;
201         yy += w;
202         xy += w;
203         x  += w;
204         y  += w;
205     }
206 }
207 
vif_filter1d(AVFilterContext * ctx,void * arg,int jobnr,int nb_jobs)208 static int vif_filter1d(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
209 {
210     ThreadData *td = arg;
211     const float *filter = td->filter;
212     const float *src = td->src;
213     float *dst = td->dst;
214     int w = td->w;
215     int h = td->h;
216     int src_stride = td->src_stride;
217     int dst_stride = td->dst_stride;
218     int filt_w = td->filter_width;
219     float *temp = td->temp[jobnr];
220     const int slice_start = (h * jobnr) / nb_jobs;
221     const int slice_end = (h * (jobnr+1)) / nb_jobs;
222 
223     for (int i = slice_start; i < slice_end; i++) {
224         /** Vertical pass. */
225         for (int j = 0; j < w; j++) {
226             float sum = 0.f;
227 
228             if (i >= filt_w / 2 && i < h - filt_w / 2 - 1) {
229                 for (int filt_i = 0; filt_i < filt_w; filt_i++) {
230                     const float filt_coeff = filter[filt_i];
231                     float img_coeff;
232                     int ii = i - filt_w / 2 + filt_i;
233 
234                     img_coeff = src[ii * src_stride + j];
235                     sum += filt_coeff * img_coeff;
236                 }
237             } else {
238                 for (int filt_i = 0; filt_i < filt_w; filt_i++) {
239                     const float filt_coeff = filter[filt_i];
240                     int ii = i - filt_w / 2 + filt_i;
241                     float img_coeff;
242 
243                     ii = ii < 0 ? -ii : (ii >= h ? 2 * h - ii - 1 : ii);
244 
245                     img_coeff = src[ii * src_stride + j];
246                     sum += filt_coeff * img_coeff;
247                 }
248             }
249 
250             temp[j] = sum;
251         }
252 
253         /** Horizontal pass. */
254         for (int j = 0; j < w; j++) {
255             float sum = 0.f;
256 
257             if (j >= filt_w / 2 && j < w - filt_w / 2 - 1) {
258                 for (int filt_j = 0; filt_j < filt_w; filt_j++) {
259                     const float filt_coeff = filter[filt_j];
260                     int jj = j - filt_w / 2 + filt_j;
261                     float img_coeff;
262 
263                     img_coeff = temp[jj];
264                     sum += filt_coeff * img_coeff;
265                 }
266             } else {
267                 for (int filt_j = 0; filt_j < filt_w; filt_j++) {
268                     const float filt_coeff = filter[filt_j];
269                     int jj = j - filt_w / 2 + filt_j;
270                     float img_coeff;
271 
272                     jj = jj < 0 ? -jj : (jj >= w ? 2 * w - jj - 1 : jj);
273 
274                     img_coeff = temp[jj];
275                     sum += filt_coeff * img_coeff;
276                 }
277             }
278 
279             dst[i * dst_stride + j] = sum;
280         }
281     }
282 
283     return 0;
284 }
285 
ff_compute_vif2(AVFilterContext * ctx,const float * ref,const float * main,int w,int h,int ref_stride,int main_stride,float * score,float * data_buf[14],float ** temp,int gnb_threads)286 int ff_compute_vif2(AVFilterContext *ctx,
287                     const float *ref, const float *main, int w, int h,
288                     int ref_stride, int main_stride, float *score,
289                     float *data_buf[14], float **temp,
290                     int gnb_threads)
291 {
292     ThreadData td;
293     float *ref_scale = data_buf[0];
294     float *main_scale = data_buf[1];
295     float *ref_sq = data_buf[2];
296     float *main_sq = data_buf[3];
297     float *ref_main = data_buf[4];
298     float *mu1 = data_buf[5];
299     float *mu2 = data_buf[6];
300     float *mu1_sq = data_buf[7];
301     float *mu2_sq = data_buf[8];
302     float *mu1_mu2 = data_buf[9];
303     float *ref_sq_filt = data_buf[10];
304     float *main_sq_filt = data_buf[11];
305     float *ref_main_filt = data_buf[12];
306 
307     float *curr_ref_scale = (float *)ref;
308     float *curr_main_scale = (float *)main;
309     int curr_ref_stride = ref_stride;
310     int curr_main_stride = main_stride;
311 
312     float num = 0.f;
313     float den = 0.f;
314 
315     for (int scale = 0; scale < 4; scale++) {
316         const float *filter = vif_filter1d_table[scale];
317         int filter_width = vif_filter1d_width1[scale];
318         const int nb_threads = FFMIN(h, gnb_threads);
319         int buf_valid_w = w;
320         int buf_valid_h = h;
321 
322         td.filter = filter;
323         td.filter_width = filter_width;
324 
325         if (scale > 0) {
326             td.src = curr_ref_scale;
327             td.dst = mu1;
328             td.w = w;
329             td.h = h;
330             td.src_stride = curr_ref_stride;
331             td.dst_stride = w;
332             td.temp = temp;
333             ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
334 
335             td.src = curr_main_scale;
336             td.dst = mu2;
337             td.src_stride = curr_main_stride;
338             ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
339 
340             vif_dec2(mu1, ref_scale, buf_valid_w, buf_valid_h, w, w);
341             vif_dec2(mu2, main_scale, buf_valid_w, buf_valid_h, w, w);
342 
343             w = buf_valid_w / 2;
344             h = buf_valid_h / 2;
345 
346             buf_valid_w = w;
347             buf_valid_h = h;
348 
349             curr_ref_scale = ref_scale;
350             curr_main_scale = main_scale;
351 
352             curr_ref_stride = w;
353             curr_main_stride = w;
354         }
355 
356         td.src = curr_ref_scale;
357         td.dst = mu1;
358         td.w = w;
359         td.h = h;
360         td.src_stride = curr_ref_stride;
361         td.dst_stride = w;
362         td.temp = temp;
363         ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
364 
365         td.src = curr_main_scale;
366         td.dst = mu2;
367         td.src_stride = curr_main_stride;
368         ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
369 
370         vif_xx_yy_xy(mu1, mu2, mu1_sq, mu2_sq, mu1_mu2, w, h);
371 
372         vif_xx_yy_xy(curr_ref_scale, curr_main_scale, ref_sq, main_sq, ref_main, w, h);
373 
374         td.src = ref_sq;
375         td.dst = ref_sq_filt;
376         td.src_stride = w;
377         ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
378 
379         td.src = main_sq;
380         td.dst = main_sq_filt;
381         td.src_stride = w;
382         ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
383 
384         td.src = ref_main;
385         td.dst = ref_main_filt;
386         ctx->internal->execute(ctx, vif_filter1d, &td, NULL, nb_threads);
387 
388         vif_statistic(mu1_sq, mu2_sq, mu1_mu2, ref_sq_filt, main_sq_filt,
389                       ref_main_filt, &num, &den, w, h);
390 
391         score[scale] = den <= FLT_EPSILON ? 1.f : num / den;
392     }
393 
394     return 0;
395 }
396 
397 #define offset_fn(type, bits)                            \
398 static void offset_##bits##bit(VIFContext *s,            \
399                                const AVFrame *ref,       \
400                                AVFrame *main, int stride)\
401 {                                                        \
402     int w = s->width;                                    \
403     int h = s->height;                                   \
404                                                          \
405     int ref_stride = ref->linesize[0];                   \
406     int main_stride = main->linesize[0];                 \
407                                                          \
408     const type *ref_ptr = (const type *) ref->data[0];   \
409     const type *main_ptr = (const type *) main->data[0]; \
410                                             \
411     const float factor = s->factor;         \
412                                             \
413     float *ref_ptr_data = s->ref_data;      \
414     float *main_ptr_data = s->main_data;    \
415                                             \
416     for (int i = 0; i < h; i++) {           \
417         for (int j = 0; j < w; j++) {       \
418             ref_ptr_data[j] = ref_ptr[j] * factor - 128.f;   \
419             main_ptr_data[j] = main_ptr[j] * factor - 128.f; \
420         }                                   \
421         ref_ptr += ref_stride / sizeof(type);   \
422         ref_ptr_data += w;                      \
423         main_ptr += main_stride / sizeof(type); \
424         main_ptr_data += w;                     \
425     } \
426 }
427 
428 offset_fn(uint8_t, 8)
429 offset_fn(uint16_t, 16)
430 
set_meta(AVDictionary ** metadata,const char * key,float d)431 static void set_meta(AVDictionary **metadata, const char *key, float d)
432 {
433     char value[257];
434     snprintf(value, sizeof(value), "%f", d);
435     av_dict_set(metadata, key, value, 0);
436 }
437 
do_vif(AVFilterContext * ctx,AVFrame * main,const AVFrame * ref)438 static AVFrame *do_vif(AVFilterContext *ctx, AVFrame *main, const AVFrame *ref)
439 {
440     VIFContext *s = ctx->priv;
441     AVDictionary **metadata = &main->metadata;
442     float score[4];
443 
444     s->factor = 1.f / (1 << (s->desc->comp[0].depth - 8));
445     if (s->desc->comp[0].depth <= 8) {
446         offset_8bit(s, ref, main, s->width);
447     } else {
448         offset_16bit(s, ref, main, s->width);
449     }
450 
451     ff_compute_vif2(ctx,
452                     s->ref_data, s->main_data, s->width,
453                     s->height, s->width, s->width,
454                     score, s->data_buf, s->temp,
455                     s->nb_threads);
456 
457     set_meta(metadata, "lavfi.vif.scale.0", score[0]);
458     set_meta(metadata, "lavfi.vif.scale.1", score[1]);
459     set_meta(metadata, "lavfi.vif.scale.2", score[2]);
460     set_meta(metadata, "lavfi.vif.scale.3", score[3]);
461 
462     for (int i = 0; i < 4; i++) {
463         s->vif_min[i]  = FFMIN(s->vif_min[i], score[i]);
464         s->vif_max[i]  = FFMAX(s->vif_max[i], score[i]);
465         s->vif_sum[i] += score[i];
466     }
467 
468     s->nb_frames++;
469 
470     return main;
471 }
472 
query_formats(AVFilterContext * ctx)473 static int query_formats(AVFilterContext *ctx)
474 {
475     static const enum AVPixelFormat pix_fmts[] = {
476         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10,
477         AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
478         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
479         AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
480         AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
481         AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ444P,
482 #define PF(suf) AV_PIX_FMT_YUV420##suf,  AV_PIX_FMT_YUV422##suf,  AV_PIX_FMT_YUV444##suf
483         PF(P9), PF(P10), PF(P12), PF(P14), PF(P16),
484         AV_PIX_FMT_NONE
485     };
486 
487     AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
488     if (!fmts_list)
489         return AVERROR(ENOMEM);
490     return ff_set_common_formats(ctx, fmts_list);
491 }
492 
config_input_ref(AVFilterLink * inlink)493 static int config_input_ref(AVFilterLink *inlink)
494 {
495     AVFilterContext *ctx  = inlink->dst;
496     VIFContext *s = ctx->priv;
497 
498     if (ctx->inputs[0]->w != ctx->inputs[1]->w ||
499         ctx->inputs[0]->h != ctx->inputs[1]->h) {
500         av_log(ctx, AV_LOG_ERROR, "Width and height of input videos must be same.\n");
501         return AVERROR(EINVAL);
502     }
503     if (ctx->inputs[0]->format != ctx->inputs[1]->format) {
504         av_log(ctx, AV_LOG_ERROR, "Inputs must be of same pixel format.\n");
505         return AVERROR(EINVAL);
506     }
507 
508     s->desc = av_pix_fmt_desc_get(inlink->format);
509     s->width = ctx->inputs[0]->w;
510     s->height = ctx->inputs[0]->h;
511     s->nb_threads = ff_filter_get_nb_threads(ctx);
512 
513     for (int i = 0; i < 4; i++) {
514         s->vif_min[i] =  DBL_MAX;
515         s->vif_max[i] = -DBL_MAX;
516     }
517 
518     for (int i = 0; i < 13; i++) {
519         if (!(s->data_buf[i] = av_calloc(s->width, s->height * sizeof(float))))
520             return AVERROR(ENOMEM);
521     }
522 
523     if (!(s->ref_data = av_calloc(s->width, s->height * sizeof(float))))
524         return AVERROR(ENOMEM);
525 
526     if (!(s->main_data = av_calloc(s->width, s->height * sizeof(float))))
527         return AVERROR(ENOMEM);
528 
529     if (!(s->temp = av_calloc(s->nb_threads, sizeof(s->temp[0]))))
530         return AVERROR(ENOMEM);
531 
532     for (int i = 0; i < s->nb_threads; i++) {
533         if (!(s->temp[i] = av_calloc(s->width, sizeof(float))))
534             return AVERROR(ENOMEM);
535     }
536 
537     return 0;
538 }
539 
process_frame(FFFrameSync * fs)540 static int process_frame(FFFrameSync *fs)
541 {
542     AVFilterContext *ctx = fs->parent;
543     VIFContext *s = fs->opaque;
544     AVFilterLink *outlink = ctx->outputs[0];
545     AVFrame *out_frame, *main_frame = NULL, *ref_frame = NULL;
546     int ret;
547 
548     ret = ff_framesync_dualinput_get(fs, &main_frame, &ref_frame);
549     if (ret < 0)
550         return ret;
551 
552     if (ctx->is_disabled || !ref_frame) {
553         out_frame = main_frame;
554     } else {
555         out_frame = do_vif(ctx, main_frame, ref_frame);
556     }
557 
558     out_frame->pts = av_rescale_q(s->fs.pts, s->fs.time_base, outlink->time_base);
559 
560     return ff_filter_frame(outlink, out_frame);
561 }
562 
563 
config_output(AVFilterLink * outlink)564 static int config_output(AVFilterLink *outlink)
565 {
566     AVFilterContext *ctx = outlink->src;
567     VIFContext *s = ctx->priv;
568     AVFilterLink *mainlink = ctx->inputs[0];
569     FFFrameSyncIn *in;
570     int ret;
571 
572     outlink->w = mainlink->w;
573     outlink->h = mainlink->h;
574     outlink->time_base = mainlink->time_base;
575     outlink->sample_aspect_ratio = mainlink->sample_aspect_ratio;
576     outlink->frame_rate = mainlink->frame_rate;
577     if ((ret = ff_framesync_init(&s->fs, ctx, 2)) < 0)
578         return ret;
579 
580     in = s->fs.in;
581     in[0].time_base = mainlink->time_base;
582     in[1].time_base = ctx->inputs[1]->time_base;
583     in[0].sync   = 2;
584     in[0].before = EXT_STOP;
585     in[0].after  = EXT_STOP;
586     in[1].sync   = 1;
587     in[1].before = EXT_STOP;
588     in[1].after  = EXT_STOP;
589     s->fs.opaque   = s;
590     s->fs.on_event = process_frame;
591 
592     return ff_framesync_configure(&s->fs);
593 }
594 
activate(AVFilterContext * ctx)595 static int activate(AVFilterContext *ctx)
596 {
597     VIFContext *s = ctx->priv;
598     return ff_framesync_activate(&s->fs);
599 }
600 
uninit(AVFilterContext * ctx)601 static av_cold void uninit(AVFilterContext *ctx)
602 {
603     VIFContext *s = ctx->priv;
604 
605     if (s->nb_frames > 0) {
606         for (int i = 0; i < 4; i++)
607             av_log(ctx, AV_LOG_INFO, "VIF scale=%d average:%f min:%f: max:%f\n",
608                    i, s->vif_sum[i] / s->nb_frames, s->vif_min[i], s->vif_max[i]);
609     }
610 
611     for (int i = 0; i < 13; i++)
612         av_freep(&s->data_buf[i]);
613 
614     av_freep(&s->ref_data);
615     av_freep(&s->main_data);
616 
617     for (int i = 0; i < s->nb_threads && s->temp; i++)
618         av_freep(&s->temp[i]);
619 
620     av_freep(&s->temp);
621 
622     ff_framesync_uninit(&s->fs);
623 }
624 
625 static const AVFilterPad vif_inputs[] = {
626     {
627         .name         = "main",
628         .type         = AVMEDIA_TYPE_VIDEO,
629     },{
630         .name         = "reference",
631         .type         = AVMEDIA_TYPE_VIDEO,
632         .config_props = config_input_ref,
633     },
634     { NULL }
635 };
636 
637 static const AVFilterPad vif_outputs[] = {
638     {
639         .name          = "default",
640         .type          = AVMEDIA_TYPE_VIDEO,
641         .config_props  = config_output,
642     },
643     { NULL }
644 };
645 
646 AVFilter ff_vf_vif = {
647     .name          = "vif",
648     .description   = NULL_IF_CONFIG_SMALL("Calculate the VIF between two video streams."),
649     .uninit        = uninit,
650     .query_formats = query_formats,
651     .priv_size     = sizeof(VIFContext),
652     .priv_class    = &vif_class,
653     .activate      = activate,
654     .inputs        = vif_inputs,
655     .outputs       = vif_outputs,
656     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
657 };
658