From 7b221a27b29c7376672d4ee60092051f6b65c978 Mon Sep 17 00:00:00 2001
From: breaker27 <mail@uwe-freese.de>
Date: Wed, 26 Dec 2018 18:16:48 +0100
Subject: [PATCH] avfilter/vf_delogo: add uglarm interpolation mode

---
 doc/filters.texi        |  28 +++++++
 libavfilter/vf_delogo.c | 214 ++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 233 insertions(+), 9 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index 65ce25bc18..792560ad79 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -7952,6 +7952,34 @@ Specify the thickness of the fuzzy edge of the rectangle (added to
 deprecated, setting higher values should no longer be necessary and
 is not recommended.
 
+@item mode
+Specify the interpolation mode used to remove the logo.
+It accepts the following values:
+@table @option
+@item xy
+Only the border pixels in straight x and y direction are considered
+to replace any logo pixel. This mode tends to flicker and to show
+horizontal and vertical lines.
+@item uglarm
+Consider the whole border for every logo pixel to replace. This mode
+uses the distance raised to the power of the given @var{exponent} as
+weight that decides to which amount every border pixel is taken into
+account. This results in a more blurred area, which tends to be less
+distracting. The uglarm mode was first implemented in VirtualDub's
+LogoAway filter and is also known from ffdshow and is the
+abbreviation for "Uwe's Great LogoAway Remove Mode".
+@end table
+The default value is @code{xy}.
+
+@item exponent
+Specify the exponent used to calculate the weight out of the
+distance in @code{uglarm} mode (weight = distance ^ @var{exponent}).
+The value @code{0} results in a logo area which has
+the same average color everywhere. The higher the value, the more
+relevant a near border pixel will get, meaning that the borders of
+the logo area are more similar to the surrounding pixels. The default
+value is @code{3}.
+
 @item show
 When set to 1, a green rectangle is drawn on the screen to simplify
 finding the right @var{x}, @var{y}, @var{w}, and @var{h} parameters.
diff --git a/libavfilter/vf_delogo.c b/libavfilter/vf_delogo.c
index 065d093641..f489c6a586 100644
--- a/libavfilter/vf_delogo.c
+++ b/libavfilter/vf_delogo.c
@@ -2,6 +2,7 @@
  * Copyright (c) 2002 Jindrich Makovicka <makovick@gmail.com>
  * Copyright (c) 2011 Stefano Sabatini
  * Copyright (c) 2013, 2015 Jean Delvare <jdelvare@suse.com>
+ * Copyright (c) 2018, 2019 Uwe Freese <mail@uwe-freese.de>
  *
  * This file is part of FFmpeg.
  *
@@ -25,8 +26,12 @@
  * A very simple tv station logo remover
  * Originally imported from MPlayer libmpcodecs/vf_delogo.c,
  * the algorithm was later improved.
+ * The "UGLARM" mode was first implemented 2001 by Uwe Freese for Virtual
+ * Dub's LogoAway filter (by Krzysztof Wojdon), taken over into ffdshow's
+ * logoaway filter (by Milan Cutka), from where it was ported to ffmpeg.
  */
 
+#include "libavutil/avassert.h"
 #include "libavutil/common.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/opt.h"
@@ -50,6 +55,10 @@
  * @param logo_w width of the logo
  * @param logo_h height of the logo
  * @param band   the size of the band around the processed area
+ * @param *uglarmtable      pointer to weight table in UGLARM interpolation mode,
+ *                          zero when x-y mode is used
+ * @param *uglarmweightsum  pointer to weight sum table in UGLARM interpolation mode,
+ *                          zero when x-y mode is used
  * @param show   show a rectangle around the processed area, useful for
  *               parameters tweaking
  * @param direct if non-zero perform in-place processing
@@ -58,7 +67,8 @@ static void apply_delogo(uint8_t *dst, int dst_linesize,
                          uint8_t *src, int src_linesize,
                          int w, int h, AVRational sar,
                          int logo_x, int logo_y, int logo_w, int logo_h,
-                         unsigned int band, int show, int direct)
+                         unsigned int band, double *uglarmtable,
+                         double *uglarmweightsum, int show, int direct)
 {
     int x, y;
     uint64_t interp, weightl, weightr, weightt, weightb, weight;
@@ -89,6 +99,7 @@ static void apply_delogo(uint8_t *dst, int dst_linesize,
     dst += (logo_y1 + 1) * dst_linesize;
     src += (logo_y1 + 1) * src_linesize;
 
+    if (!uglarmtable) {
     for (y = logo_y1+1; y < logo_y2; y++) {
         left_sample = topleft[src_linesize*(y-logo_y1)]   +
                       topleft[src_linesize*(y-logo_y1-1)] +
@@ -151,12 +162,154 @@ static void apply_delogo(uint8_t *dst, int dst_linesize,
         dst += dst_linesize;
         src += src_linesize;
     }
+    } else {
+        int bx, by, table_stride;
+        double interpd;
+        double *table_t, *table_b, *table_l, *table_r;
+
+        table_stride = logo_w - 1;
+
+        for (y = 1; y < logo_y2 - logo_y1; y++) {
+            for (x = 1, xdst = dst + logo_x1 + 1, xsrc = src + logo_x1 + 1;
+                x < logo_x2 - logo_x1;
+                x++, xdst++, xsrc++) {
+
+                if (show && (y == 1 || y == logo_y2 - logo_y1 - 1 ||
+                             x == 1 || x == logo_x2 - logo_x1 - 1)) {
+                    *xdst = 0;
+                    continue;
+                }
+
+                table_t = uglarmtable + x + table_stride * y;
+                table_b = uglarmtable + x + table_stride * (logo_h - y - 1);
+                table_l = uglarmtable + table_stride * (y - 1) + x;
+                table_r = uglarmtable + table_stride * (y - 1) + logo_w - x - 1;
+
+                interpd = 0;
+
+                /* top+bottom on the left of the current point */
+                for (bx = 0; bx < x; bx++) {
+                    interpd += topleft[bx] * *table_t;
+                    interpd += botleft[bx] * *table_b;
+                    table_t--;
+                    table_b--;
+                }
+                /* top+bottom on the right of the current point */
+                for (; bx < logo_w; bx++) {
+                    interpd += topleft[bx] * *table_t;
+                    interpd += botleft[bx] * *table_b;
+                    table_t++;
+                    table_b++;
+                }
+                /* left+right above the current point */
+                for (by = 1; by < y; by++) {
+                    interpd += topleft[by * src_linesize] * *table_l;
+                    interpd += topleft[by * src_linesize + table_stride] * *table_r;
+                    table_l -= table_stride;
+                    table_r -= table_stride;
+                }
+                /* left+right below the current point */
+                for (; by < logo_h - 1; by++) {
+                    interpd += topleft[by * src_linesize] * *table_l;
+                    interpd += topleft[by * src_linesize + table_stride] * *table_r;
+                    table_l += table_stride;
+                    table_r += table_stride;
+                }
+
+                av_assert2(table_t == uglarmtable + (logo_w - x) + table_stride * y);
+                av_assert2(table_b == uglarmtable + (logo_w - x) + table_stride * (logo_h - y - 1));
+                av_assert2(table_l == uglarmtable + table_stride * (logo_h - y - 1) + x);
+                av_assert2(table_r == uglarmtable + table_stride * (logo_h - y - 1) + logo_w - x - 1);
+
+                interp = (uint64_t)(interpd /
+                    uglarmweightsum[x - 1 + (y - 1) * (logo_w - 2)]);
+                *xdst = interp;
+            }
+
+            dst += dst_linesize;
+            src += src_linesize;
+        }
+    }
+}
+
+/**
+ * Calculate the lookup tables to be used in UGLARM interpolation mode.
+ *
+ * @param *uglarmtable      Pointer to table containing weights for each possible
+ *                          diagonal distance between a border pixel and an inner
+ *                          logo pixel.
+ * @param *uglarmweightsum  Pointer to a table containing the weight sum to divide
+ *                          by for each pixel within the logo area.
+ * @param sar               The sar to take into account when calculating lookup
+ *                          tables.
+ * @param logo_w            width of the logo
+ * @param logo_h            height of the logo
+ * @param exponent          exponent used in uglarm interpolation
+ */
+static void calc_uglarm_tables(double *uglarmtable, double *uglarmweightsum,
+                               AVRational sar, int logo_w, int logo_h,
+                               float exponent)
+{
+    double aspect = (double)sar.num / sar.den;
+    double aspect2 = aspect * aspect;
+    int x, y;
+
+    /* uglarmtable will contain a weight for each possible diagonal distance
+     * between a border pixel and an inner logo pixel. The maximum distance in
+     * each direction between border and an inner pixel can be logo_w - 1. The
+     * weight of a border pixel which is x,y pixels away is stored at position
+     * x + y * (logo_w - 1). */
+    for (y = 0; y < logo_h - 1; y++)
+        for (x = 0; x < logo_w - 1; x++) {
+            if (x + y != 0) {
+                double d = pow(x * x * aspect2 + y * y, exponent / 2);
+                uglarmtable[x + y * (logo_w - 1)] = 1.0 / d;
+            } else {
+                uglarmtable[x + y * (logo_w - 1)] = 1.0;
+            }
+        }
+
+    /* uglarmweightsum will contain the sum of all weights which is used when
+     * an inner pixel of the logo at position x,y is calculated out of the
+     * border pixels. The aggregated value has to be divided by that. The value
+     * to use for the inner 1-based logo position x,y is stored at
+     * (x - 1) + (y - 1) * (logo_w - 2). */
+    for (y = 1; y < logo_h - 1; y++)
+        for (x = 1; x < logo_w - 1; x++) {
+            double weightsum = 0;
+
+            for (int bx = 0; bx < logo_w; bx++) {
+                /* top border */
+                weightsum += uglarmtable[abs(bx - x) + y * (logo_w - 1)];
+                /* bottom border */
+                weightsum += uglarmtable[abs(bx - x) + (logo_h - y - 1) * (logo_w - 1)];
+            }
+
+            for (int by = 1; by < logo_h - 1; by++) {
+                /* left border */
+                weightsum += uglarmtable[x + abs(by - y) * (logo_w - 1)];
+                /* right border */
+                weightsum += uglarmtable[(logo_w - x - 1) + abs(by - y) * (logo_w - 1)];
+            }
+
+            uglarmweightsum[(x - 1) + (y - 1) * (logo_w - 2)] = weightsum;
+        }
 }
 
+enum mode {
+    MODE_XY,
+    MODE_UGLARM,
+    MODE_NB
+};
+
+#define MAX_SUB 2
+
 typedef struct DelogoContext {
     const AVClass *class;
-    int x, y, w, h, band, show;
-}  DelogoContext;
+    int x, y, w, h, band, mode, show;
+    float exponent;
+    double *uglarmtable[MAX_SUB + 1][MAX_SUB + 1], *uglarmweightsum[MAX_SUB + 1][MAX_SUB + 1];
+} DelogoContext;
 
 #define OFFSET(x) offsetof(DelogoContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
@@ -171,6 +324,10 @@ static const AVOption delogo_options[]= {
     { "band", "set delogo area band size", OFFSET(band), AV_OPT_TYPE_INT, { .i64 =  0 },  0, INT_MAX, FLAGS },
     { "t",    "set delogo area band size", OFFSET(band), AV_OPT_TYPE_INT, { .i64 =  0 },  0, INT_MAX, FLAGS },
 #endif
+    { "mode", "set the interpolation mode",OFFSET(mode), AV_OPT_TYPE_INT, { .i64 = MODE_XY }, MODE_XY, MODE_NB-1, FLAGS, "mode" },
+        { "xy",     "use pixels in straight x and y direction",  OFFSET(mode), AV_OPT_TYPE_CONST, { .i64 = MODE_XY },     0, 0, FLAGS, "mode" },
+        { "uglarm", "UGLARM mode, use full border",              OFFSET(mode), AV_OPT_TYPE_CONST, { .i64 = MODE_UGLARM }, 0, 0, FLAGS, "mode" },
+    { "exponent","exponent used for UGLARM interpolation", OFFSET(exponent), AV_OPT_TYPE_FLOAT, { .dbl = 3.0 }, 0, 6, FLAGS },
     { "show", "show delogo area",          OFFSET(show), AV_OPT_TYPE_BOOL,{ .i64 =  0 },  0, 1,       FLAGS },
     { NULL }
 };
@@ -215,8 +372,8 @@ static av_cold int init(AVFilterContext *ctx)
 #else
     s->band = 1;
 #endif
-    av_log(ctx, AV_LOG_VERBOSE, "x:%d y:%d, w:%d h:%d band:%d show:%d\n",
-           s->x, s->y, s->w, s->h, s->band, s->show);
+    av_log(ctx, AV_LOG_VERBOSE, "x:%d y:%d, w:%d h:%d band:%d mode:%d exponent:%f show:%d\n",
+           s->x, s->y, s->w, s->h, s->band, s->mode, s->exponent, s->show);
 
     s->w += s->band*2;
     s->h += s->band*2;
@@ -226,6 +383,17 @@ static av_cold int init(AVFilterContext *ctx)
     return 0;
 }
 
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    DelogoContext *s = ctx->priv;
+
+    for (int hsub = 0; hsub <= MAX_SUB; hsub++)
+        for (int vsub = 0; vsub <= MAX_SUB; vsub++) {
+            av_freep(&s->uglarmtable[hsub][vsub]);
+            av_freep(&s->uglarmweightsum[hsub][vsub]);
+        }
+}
+
 static int config_input(AVFilterLink *inlink)
 {
     DelogoContext *s = inlink->dst->priv;
@@ -270,20 +438,47 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
     if (!sar.num)
         sar.num = sar.den = 1;
 
+    if (s->mode == MODE_UGLARM)
+        av_assert0(hsub0 <= MAX_SUB && vsub0 <= MAX_SUB);
+
     for (plane = 0; plane < desc->nb_components; plane++) {
         int hsub = plane == 1 || plane == 2 ? hsub0 : 0;
         int vsub = plane == 1 || plane == 2 ? vsub0 : 0;
 
+        /* Up and left borders were rounded down, inject lost bits
+         * into width and height to avoid error accumulation */
+        int logo_w = AV_CEIL_RSHIFT(s->w + (s->x & ((1<<hsub)-1)), hsub);
+        int logo_h = AV_CEIL_RSHIFT(s->h + (s->y & ((1<<vsub)-1)), vsub);
+
+        /* Init lookup tables once */
+        if ((s->mode == MODE_UGLARM) && (!s->uglarmtable[hsub][vsub])) {
+            s->uglarmtable[hsub][vsub] =
+                av_malloc_array((logo_w - 1) * (logo_h - 1), sizeof(*s->uglarmtable[hsub][vsub]));
+
+            if (!s->uglarmtable[hsub][vsub])
+                return AVERROR(ENOMEM);
+
+            s->uglarmweightsum[hsub][vsub] =
+                av_malloc_array((logo_w - 2) * (logo_h - 2), sizeof(*s->uglarmweightsum[hsub][vsub]));
+
+            if (!s->uglarmweightsum[hsub][vsub])
+                return AVERROR(ENOMEM);
+
+            calc_uglarm_tables(s->uglarmtable[hsub][vsub],
+                            s->uglarmweightsum[hsub][vsub],
+                            sar, logo_w, logo_h, s->exponent);
+        }
+
         apply_delogo(out->data[plane], out->linesize[plane],
                      in ->data[plane], in ->linesize[plane],
                      AV_CEIL_RSHIFT(inlink->w, hsub),
                      AV_CEIL_RSHIFT(inlink->h, vsub),
                      sar, s->x>>hsub, s->y>>vsub,
-                     /* Up and left borders were rounded down, inject lost bits
-                      * into width and height to avoid error accumulation */
-                     AV_CEIL_RSHIFT(s->w + (s->x & ((1<<hsub)-1)), hsub),
-                     AV_CEIL_RSHIFT(s->h + (s->y & ((1<<vsub)-1)), vsub),
+                     logo_w,
+                     logo_h,
                      s->band>>FFMIN(hsub, vsub),
+                     s->uglarmtable[hsub][vsub],
+                     s->uglarmweightsum[hsub][vsub],
                      s->show, direct);
     }
 
@@ -317,6 +512,7 @@ AVFilter ff_vf_delogo = {
     .priv_size     = sizeof(DelogoContext),
     .priv_class    = &delogo_class,
     .init          = init,
+    .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = avfilter_vf_delogo_inputs,
     .outputs       = avfilter_vf_delogo_outputs,
-- 
2.11.0

