aboutsummaryrefslogtreecommitdiffstats
path: root/libavfilter/vf_blockdetect.c
blob: 624dcfdeda66ed21e607e3711f7c9854375dd4ba (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
/*
 * 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 blockdetect filter
 *
 * Implementing:
 * Remco Muijs and Ihor Kirenko: "A no-reference blocking artifact measure for adaptive video processing." 2005 13th European signal processing conference. IEEE, 2005.
 * http://www.eurasip.org/Proceedings/Eusipco/Eusipco2005/defevent/papers/cr1042.pdf
 *
 * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
 */

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

typedef struct BLKContext {
    const AVClass *class;

    int hsub, vsub;
    int nb_planes;

    int period_min;    // minimum period to search for
    int period_max;    // maximum period to search for
    int planes;        // number of planes to filter

    double block_total;
    uint64_t nb_frames;

    float *gradients;
} BLKContext;

#define OFFSET(x) offsetof(BLKContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption blockdetect_options[] = {
    { "period_min", "Minimum period to search for", OFFSET(period_min), AV_OPT_TYPE_INT, {.i64=3}, 2, 32, FLAGS},
    { "period_max", "Maximum period to search for", OFFSET(period_max), AV_OPT_TYPE_INT, {.i64=24}, 2, 64, FLAGS},
    { "planes",        "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT, {.i64=1}, 0, 15, FLAGS },
    { NULL }
};

AVFILTER_DEFINE_CLASS(blockdetect);

static av_cold int blockdetect_init(AVFilterContext *ctx)
{
    return 0;
}

static int blockdetect_config_input(AVFilterLink *inlink)
{
    AVFilterContext *ctx = inlink->dst;
    BLKContext      *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);

    s->gradients = av_calloc(bufsize, sizeof(*s->gradients));

    if (!s->gradients)
        return AVERROR(ENOMEM);

    return 0;
}

static float calculate_blockiness(BLKContext *s, int w, int h,
                                  float *grad, int grad_linesize,
                                  uint8_t* src, int src_linesize)
{
    float block = 0.0f;
    float nonblock = 0.0f;
    int block_count = 0;
    int nonblock_count = 0;
    float ret = 0;

    // Calculate BS in horizontal and vertical directions according to (1)(2)(3).
    // Also try to find integer pixel periods (grids) even for scaled images.
    // In case of fractional periods, FFMAX of current and neighbor pixels
    // can help improve the correlation with MQS.
    // Skip linear correction term (4)(5), as it appears only valid for their own test samples.

    // horizontal blockiness (fixed width)
    for (int j = 1; j < h; j++) {
        for (int i = 3; i < w - 4; i++) {
            float temp = 0.0f;
            grad[j * grad_linesize + i] =
                    abs(src[j * src_linesize + i + 0] - src[j * src_linesize + i + 1]);
            temp += abs(src[j * src_linesize + i + 1] - src[j * src_linesize + i + 2]);
            temp += abs(src[j * src_linesize + i + 2] - src[j * src_linesize + i + 3]);
            temp += abs(src[j * src_linesize + i + 3] - src[j * src_linesize + i + 4]);
            temp += abs(src[j * src_linesize + i - 0] - src[j * src_linesize + i - 1]);
            temp += abs(src[j * src_linesize + i - 1] - src[j * src_linesize + i - 2]);
            temp += abs(src[j * src_linesize + i - 2] - src[j * src_linesize + i - 3]);
            temp = FFMAX(1, temp);
            grad[j * grad_linesize + i] /= temp;

            // use first row to store acculated results
            grad[i] += grad[j * grad_linesize + i];
        }
    }

    // find horizontal period
    for (int period = s->period_min; period < s->period_max + 1; period++) {
        float temp;
        block = 0;
        nonblock = 0;
        block_count = 0;
        nonblock_count = 0;
        for (int i = 3; i < w - 4; i++) {
            if ((i % period) == (period - 1)) {
                block += FFMAX(FFMAX(grad[i + 0], grad[i + 1]), grad[i - 1]);
                block_count++;
            } else {
                nonblock += grad[i];
                nonblock_count++;
            }
        }
        temp = (block / block_count) / (nonblock / nonblock_count);
        ret = FFMAX(ret, temp);
    }

    // vertical blockiness (fixed height)
    block_count = 0;
    for (int j = 3; j < h - 4; j++) {
        for (int i = 1; i < w; i++) {
            float temp = 0.0f;
            grad[j * grad_linesize + i] =
                    abs(src[(j + 0) * src_linesize + i] - src[(j + 1) * src_linesize + i]);
            temp += abs(src[(j + 1) * src_linesize + i] - src[(j + 2) * src_linesize + i]);
            temp += abs(src[(j + 2) * src_linesize + i] - src[(j + 3) * src_linesize + i]);
            temp += abs(src[(j + 3) * src_linesize + i] - src[(j + 4) * src_linesize + i]);
            temp += abs(src[(j - 0) * src_linesize + i] - src[(j - 1) * src_linesize + i]);
            temp += abs(src[(j - 1) * src_linesize + i] - src[(j - 2) * src_linesize + i]);
            temp += abs(src[(j - 2) * src_linesize + i] - src[(j - 3) * src_linesize + i]);
            temp = FFMAX(1, temp);
            grad[j * grad_linesize + i] /= temp;

            // use first column to store accumulated results
            grad[j * grad_linesize] += grad[j * grad_linesize + i];
        }
    }

    // find vertical period
    for (int period = s->period_min; period < s->period_max + 1; period++) {
        float temp;
        block = 0;
        nonblock = 0;
        block_count = 0;
        nonblock_count = 0;
        for (int j = 3; j < h - 4; j++) {
            if ((j % period) == (period - 1)) {
                block += FFMAX(FFMAX(grad[(j + 0) * grad_linesize],
                                     grad[(j + 1) * grad_linesize]),
                                     grad[(j - 1) * grad_linesize]);
                block_count++;
            } else {
                nonblock += grad[j * grad_linesize];
                nonblock_count++;
            }
        }
        temp = (block / block_count) / (nonblock / nonblock_count);
        ret = FFMAX(ret, temp);
    }

    // return highest value of horz||vert
    return ret;
}

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 blockdetect_filter_frame(AVFilterLink *inlink, AVFrame *in)
{
    AVFilterContext *ctx  = inlink->dst;
    BLKContext *s         = ctx->priv;
    AVFilterLink *outlink = ctx->outputs[0];

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

    float *gradients   = s->gradients;

    float block = 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++;

        block += calculate_blockiness(s, w, h, gradients, w, in->data[plane], in->linesize[plane]);
    }

    if (nplanes)
        block /= nplanes;

    s->block_total += block;

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

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

    s->nb_frames = inlink->frame_count_in;

    return ff_filter_frame(outlink, in);
}

static av_cold void blockdetect_uninit(AVFilterContext *ctx)
{
    BLKContext *s = ctx->priv;

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

    av_freep(&s->gradients);
}

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 blockdetect_inputs[] = {
    {
        .name         = "default",
        .type         = AVMEDIA_TYPE_VIDEO,
        .config_props = blockdetect_config_input,
        .filter_frame = blockdetect_filter_frame,
    },
};

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

const AVFilter ff_vf_blockdetect = {
    .name          = "blockdetect",
    .description   = NULL_IF_CONFIG_SMALL("Blockdetect filter."),
    .priv_size     = sizeof(BLKContext),
    .init          = blockdetect_init,
    .uninit        = blockdetect_uninit,
    FILTER_PIXFMTS_ARRAY(pix_fmts),
    FILTER_INPUTS(blockdetect_inputs),
    FILTER_OUTPUTS(blockdetect_outputs),
    .priv_class    = &blockdetect_class,
    .flags         = AVFILTER_FLAG_METADATA_ONLY,
};