aboutsummaryrefslogtreecommitdiffstats
path: root/libavfilter/vf_blurdetect.c
blob: 0e08ba96de5e52f74c4296d75eb5ac5ef9b4b688 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
/*
 * Copyright (c) 2021 Thilo Borgmann <thilo.borgmann _at_ mail.de>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * No-reference blurdetect filter
 *
 * Implementing:
 * Marziliano, Pina, et al. "A no-reference perceptual blur metric." Proceedings.
 * International conference on image processing. Vol. 3. IEEE, 2002.
 * https://infoscience.epfl.ch/record/111802/files/14%20A%20no-reference%20perceptual%20blur%20metric.pdf
 *
 * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
 */

#include "libavutil/imgutils.h"
#include "libavutil/opt.h"
#include "libavutil/qsort.h"
#include "internal.h"
#include "edge_common.h"

static int comp(const float *a,const float *b)
{
    return FFDIFFSIGN(*a, *b);
}

typedef struct BLRContext {
    const AVClass *class;

    int hsub, vsub;
    int nb_planes;

    float   low, high;
    uint8_t low_u8, high_u8;
    int     radius;        // radius during local maxima detection
    int     block_pct;     // percentage of "sharpest" blocks in the image to use for bluriness calculation
    int     block_width;   // width for block abbreviation
    int     block_height;  // height for block abbreviation
    int     planes;        // number of planes to filter

    double   blur_total;
    uint64_t nb_frames;

    float    *blks;
    uint8_t  *filterbuf;
    uint8_t  *tmpbuf;
    uint16_t *gradients;
    int8_t   *directions;
} BLRContext;

#define OFFSET(x) offsetof(BLRContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption blurdetect_options[] = {
    { "high",          "set high threshold", OFFSET(high), AV_OPT_TYPE_FLOAT, {.dbl=30/255.}, 0, 1, FLAGS },
    { "low",           "set low threshold",  OFFSET(low),  AV_OPT_TYPE_FLOAT, {.dbl=15/255.}, 0, 1, FLAGS },
    { "radius",        "search radius for maxima detection", OFFSET(radius), AV_OPT_TYPE_INT, {.i64=50}, 1, 100, FLAGS },
    { "block_pct",     "block pooling threshold when calculating blurriness", OFFSET(block_pct), AV_OPT_TYPE_INT, {.i64=80}, 1, 100, FLAGS },
    { "block_width",   "block size for block-based abbreviation of blurriness", OFFSET(block_width), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
    { "block_height",  "block size for block-based abbreviation of blurriness", OFFSET(block_height), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
    { "planes",        "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT, {.i64=1}, 0, 15, FLAGS },
    { NULL }
};

AVFILTER_DEFINE_CLASS(blurdetect);

static av_cold int blurdetect_init(AVFilterContext *ctx)
{
    BLRContext *s = ctx->priv;

    s->low_u8  = s->low  * 255. + .5;
    s->high_u8 = s->high * 255. + .5;

    return 0;
}

static int blurdetect_config_input(AVFilterLink *inlink)
{
    AVFilterContext *ctx = inlink->dst;
    BLRContext      *s   = ctx->priv;
    const int bufsize    = inlink->w * inlink->h;
    const AVPixFmtDescriptor *pix_desc;

    pix_desc = av_pix_fmt_desc_get(inlink->format);
    s->hsub = pix_desc->log2_chroma_w;
    s->vsub = pix_desc->log2_chroma_h;
    s->nb_planes = av_pix_fmt_count_planes(inlink->format);

    if (s->block_width  < 1 || s->block_height < 1) {
        s->block_width  = inlink->w;
        s->block_height = inlink->h;
    }

    s->tmpbuf     = av_malloc(bufsize);
    s->filterbuf  = av_malloc(bufsize);
    s->gradients  = av_calloc(bufsize, sizeof(*s->gradients));
    s->directions = av_malloc(bufsize);
    s->blks       = av_calloc((inlink->w / s->block_width) * (inlink->h / s->block_height),
                              sizeof(*s->blks));

    if (!s->tmpbuf || !s->filterbuf || !s->gradients || !s->directions || !s->blks)
        return AVERROR(ENOMEM);

    return 0;
}

// edge width is defined as the distance between surrounding maxima of the edge pixel
static float edge_width(BLRContext *blr, int i, int j, int8_t dir, int w, int h,
                        int edge, const uint8_t *src, int src_linesize)
{
    float width = 0;
    int dX, dY;
    int sign;
    int tmp;
    int p1;
    int p2;
    int k, x, y;
    int radius = blr->radius;

    switch(dir) {
    case DIRECTION_HORIZONTAL: dX = 1; dY =  0; break;
    case DIRECTION_VERTICAL:   dX = 0; dY =  1; break;
    case DIRECTION_45UP:       dX = 1; dY = -1; break;
    case DIRECTION_45DOWN:     dX = 1; dY =  1; break;
    default:                   dX = 1; dY =  1; break;
    }

    // determines if search in direction dX/dY is looking for a maximum or minimum
    sign = src[j * src_linesize + i] > src[(j - dY) * src_linesize + i - dX] ? 1 : -1;

    // search in -(dX/dY) direction
    for (k = 0; k < radius; k++) {
        x = i - k*dX;
        y = j - k*dY;
        p1 = y * src_linesize + x;
        x -= dX;
        y -= dY;
        p2 = y * src_linesize + x;
        if (x < 0 || x >= w || y < 0 || y >= h)
            return 0;

        tmp = (src[p1] - src[p2]) * sign;

        if (tmp <= 0) // local maximum found
            break;
    }
    width += k;

    // search in +(dX/dY) direction
    for (k = 0; k < radius; k++) {
        x = i + k * dX;
        y = j + k * dY;
        p1 = y * src_linesize + x;
        x += dX;
        y += dY;
        p2 = y * src_linesize + x;
        if (x < 0 || x >= w || y < 0 || y >= h)
            return 0;

        tmp = (src[p1] - src[p2]) * sign;

        if (tmp >= 0) // local maximum found
            break;
    }
    width += k;

    // for 45 degree directions approximate edge width in pixel units: 0.7 ~= sqrt(2)/2
    if (dir == DIRECTION_45UP || dir == DIRECTION_45DOWN)
        width *= 0.7;

    return width;
}

static float calculate_blur(BLRContext *s, int w, int h, int hsub, int vsub,
                            int8_t* dir, int dir_linesize,
                            uint8_t* dst, int dst_linesize,
                            uint8_t* src, int src_linesize)
{
    float total_width = 0.0;
    int block_count;
    double block_total_width;

    int i, j;
    int blkcnt = 0;

    float *blks = s->blks;
    float block_pool_threshold = s->block_pct / 100.0;

    int block_width  = AV_CEIL_RSHIFT(s->block_width,  hsub);
    int block_height = AV_CEIL_RSHIFT(s->block_height, vsub);
    int brows = h / block_height;
    int bcols = w / block_width;

    for (int blkj = 0; blkj < brows; blkj++) {
        for (int blki = 0; blki < bcols; blki++) {
            block_total_width = 0.0;
            block_count = 0;
            for (int inj = 0; inj < block_height; inj++) {
                for (int ini = 0; ini < block_width; ini++) {
                    i = blki * block_width + ini;
                    j = blkj * block_height + inj;

                    if (dst[j * dst_linesize + i] > 0) {
                        float width = edge_width(s, i, j, dir[j*dir_linesize+i],
                                                 w, h, dst[j*dst_linesize+i],
                                                 src, src_linesize);
                        if (width > 0.001) { // throw away zeros
                            block_count++;
                            block_total_width += width;
                        }
                    }
                }
            }
            // if not enough edge pixels in a block, consider it smooth
            if (block_total_width >= 2 && block_count) {
                blks[blkcnt] = block_total_width / block_count;
                blkcnt++;
            }
        }
    }

    // simple block pooling by sorting and keeping the sharper blocks
    AV_QSORT(blks, blkcnt, float, comp);
    blkcnt = ceil(blkcnt * block_pool_threshold);
    for (int i = 0; i < blkcnt; i++) {
        total_width += blks[i];
    }

    return  total_width / blkcnt;
}

static void set_meta(AVDictionary **metadata, const char *key, float d)
{
    char value[128];
    snprintf(value, sizeof(value), "%f", d);
    av_dict_set(metadata, key, value, 0);
}

static int blurdetect_filter_frame(AVFilterLink *inlink, AVFrame *in)
{
    AVFilterContext *ctx  = inlink->dst;
    BLRContext *s         = ctx->priv;
    AVFilterLink *outlink = ctx->outputs[0];

    const int inw = inlink->w;
    const int inh = inlink->h;

    uint8_t *tmpbuf     = s->tmpbuf;
    uint8_t *filterbuf  = s->filterbuf;
    uint16_t *gradients = s->gradients;
    int8_t *directions  = s->directions;

    float blur = 0.0f;
    int nplanes = 0;
    AVDictionary **metadata;
    metadata = &in->metadata;

    for (int plane = 0; plane < s->nb_planes; plane++) {
        int hsub = plane == 1 || plane == 2 ? s->hsub : 0;
        int vsub = plane == 1 || plane == 2 ? s->vsub : 0;
        int w = AV_CEIL_RSHIFT(inw, hsub);
        int h = AV_CEIL_RSHIFT(inh, vsub);

        if (!((1 << plane) & s->planes))
            continue;

        nplanes++;

        // gaussian filter to reduce noise
        ff_gaussian_blur(w, h,
                         filterbuf,  w,
                         in->data[plane], in->linesize[plane]);

        // compute the 16-bits gradients and directions for the next step
        ff_sobel(w, h, gradients, w, directions, w, filterbuf, w);

        // non_maximum_suppression() will actually keep & clip what's necessary and
        // ignore the rest, so we need a clean output buffer
        memset(tmpbuf, 0, inw * inh);
        ff_non_maximum_suppression(w, h, tmpbuf, w, directions, w, gradients, w);


        // keep high values, or low values surrounded by high values
        ff_double_threshold(s->low_u8, s->high_u8, w, h,
                            tmpbuf, w, tmpbuf, w);

        blur += calculate_blur(s, w, h, hsub, vsub, directions, w,
                              tmpbuf, w, filterbuf, w);
    }

    if (nplanes)
        blur /= nplanes;

    s->blur_total += blur;

    // write stats
    av_log(ctx, AV_LOG_VERBOSE, "blur: %.7f\n", blur);

    set_meta(metadata, "lavfi.blur", blur);

    s->nb_frames = inlink->frame_count_in;

    return ff_filter_frame(outlink, in);
}

static av_cold void blurdetect_uninit(AVFilterContext *ctx)
{
    BLRContext *s = ctx->priv;

    if (s->nb_frames > 0) {
        av_log(ctx, AV_LOG_INFO, "blur mean: %.7f\n",
               s->blur_total / s->nb_frames);
    }

    av_freep(&s->tmpbuf);
    av_freep(&s->filterbuf);
    av_freep(&s->gradients);
    av_freep(&s->directions);
    av_freep(&s->blks);
}

static const enum AVPixelFormat pix_fmts[] = {
    AV_PIX_FMT_GRAY8,
    AV_PIX_FMT_GBRP,     AV_PIX_FMT_GBRAP,
    AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV420P,
    AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV440P,
    AV_PIX_FMT_YUV411P,  AV_PIX_FMT_YUV410P,
    AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P,
    AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
    AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
    AV_PIX_FMT_NONE
};

static const AVFilterPad blurdetect_inputs[] = {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .config_props = blurdetect_config_input,
        .filter_frame = blurdetect_filter_frame,
    },
};

static const AVFilterPad blurdetect_outputs[] = {
    {
        .name = "default",
        .type = AVMEDIA_TYPE_VIDEO,
    },
};

const AVFilter ff_vf_blurdetect = {
    .name          = "blurdetect",
    .description   = NULL_IF_CONFIG_SMALL("Blurdetect filter."),
    .priv_size     = sizeof(BLRContext),
    .init          = blurdetect_init,
    .uninit        = blurdetect_uninit,
    FILTER_PIXFMTS_ARRAY(pix_fmts),
    FILTER_INPUTS(blurdetect_inputs),
    FILTER_OUTPUTS(blurdetect_outputs),
    .priv_class    = &blurdetect_class,
    .flags         = AVFILTER_FLAG_METADATA_ONLY,
};