Hello,
here's a new version of the patch.
Thanks for the infos. I used the raw output of a small test video (where
delogo is applied in both modes) before and after the changes to make
sure the output is bytewise identical (the changes don't change the output).
In general I want to say that it seems to me that *some* of the points
go now in a more philosophical direction.
I prefer code easy to understand and assume that compilers optimize
much. Yes, there may be many possibilities to probably "optimize"
something, but I tend to believe that many times this is not needed nor
helpful, because it doesn't really optimize and complicates the code.
Additionally, when I don't have complete and functioning code to replace
my code (the same what's expected from me), I'm not willing to spend
many hours to guess what could be meant.
I hope that not so many additional patches are needed anymore. I
understand that coding styles, syntax etc. shall be corrected, but hope
that we don't have to discuss too much alternative ways of implementing
basically the same.
Changes since the last version of the patch (mail from 29.12. 21:38),
according the comments since then:
- change include order at the beginning of the file
- change loop format (linebreaks)
- change loop borders
- change indentation (line 175)
- moved init code (create tables) to config_input function
- used av_malloc_array instead of av_malloc. Avoid the cast. Use
variable in sizeof(...).
- copyright 2018, 2019 - happy new year BTW ;-)
Comments and remaining open points from the mails:
+ for (y = logo_y1 + 1; y < logo_y2; y++) {
+ for (x = logo_x1 + 1,
+ xdst = dst + logo_x1 + 1,
+ xsrc = src + logo_x1 + 1; x < logo_x2; x++, xdst++, xsrc++) {
I think a line break after the semicolons would make this easier to
understand.
Hm. I used the same format as in the original code.
Nonetheless, I changed the format now, because I changed the loop
borders as requested and the loops are now different anyway.
+ for (bx = 0; bx < logo_w; bx++) {
+ interpd += topleft[bx] *
+ uglarmtable[abs(bx - (x - logo_x1)) + (y - logo_y1) *
(logo_w - 1)];
+ interpd += botleft[bx] *
+ uglarmtable[abs(bx - (x - logo_x1)) + (logo_h - (y -
logo_y1) - 1) * (logo_w - 1)];
+ }
This can be optimized, and since it is the inner loop of the filter, I
think it is worth it. You can declare a pointer that will stay the same
for the whole y loop:
double *xweight = uglarmtable + (y - logo_y1) * (logo_w - 1);
and then use it in that loop:
interpd += ... * xweight[abs(bx - (x - logo_x1))];
It avoids a lot of multiplications.
I'm not sure about this point. First, I would absolutely assume from the
compiler that it optimizes expressions like "(logo_w - 1)" or a fixed
offset to access the array in the loop and that they are only calculated
once.
Secondly, I don't exactly understand how *xweight in your example should
be used (and would mean smaller or easier code).
@All: What is the opinion about changing this loop regarding use of an
additional xweight pointer?
+
+ for (by = 1; by < logo_h - 1; by++) {
+ interpd += topleft[by * src_linesize] *
+ uglarmtable[(x - logo_x1) + abs(by - (y - logo_y1)) *
(logo_w - 1)];
+ interpd += topleft[by * src_linesize + (logo_w - 1)] *
+ uglarmtable[logo_w - (x - logo_x1) - 1 + abs(by - (y -
logo_y1)) * (logo_w - 1)];
+ }
This one is more tricky to optimize, because of the abs() within the
multiplication, but it can be done by splitting the loop in two:
for (by = 1; by < y; by++) {
interpd += ... * yweight[x - logo_x1];
yweight -= logo_w_minus_one;
}
for (; by < logo_h_minus_one; by++) {
interpd += ... * yweight[x - logo_x1];
yweight += logo_w_minus_one;
}
av_assert2(yweight == the_correct_value);
In fact, I think even the x loop would be a little more readable if it
was split in two like that.
Sorry, I don't understand. Please give me a complete example that
replaces the previous for loop.
+
+ interp = (uint64_t)(interpd /
+ uglarmweightsum[(x - logo_x1) - 1 + (y - logo_y1 - 1) *
(logo_w - 2)]);
The cast to uint64_t seems suspicious. Can you explain?
Every pixel value of the inner logo area is an integer. Only for the
calculation of the weighted average, all values use floats. At the end,
it is rounded (truncated) to an int.
Should work - and did work for 17 years...
+ *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;
Tiny optimization:
double aspect2 = aspect * aspect;
for use later.
I wouldn't consider this an optimization. First, I assume the compiler
to only calculate "aspect * aspect" once in that loop (as well as "y *
y" which doesn't change in the inner loop). Second, the code with using
the additional variable makes the code more complex and third, this loop
is only calculated once at startup.
@All: What are your opinions?
+ double d = pow(sqrt(x * x * aspect * aspect + y * y),
exponent);
pow(x * x * aspect2 + y * y, exponent / 2);
Hm. Again, I'm unsure if this "optimization" is worth it. I wouldn't do
this normally.
Reasons: Again, I think the compiler would optimize it. At least the
compiled ffmpeg binaries are exactly the same size... And the original
code explains better the calculation: Calculate the distance
(*Pythagorean theorem, c = sqrt(a² + b²), and then calculate the
weighted distance value with the power. Again, this is only run once at
startup
*
*@All: Other opinions?
*
+#define MAX_PLANES 10
You could use FF_ARRAY_ELEMS(AVPixFmtDescriptor.comp), and the
consistency would be guaranteed. Well, that syntax is not valid, but it
can be expressed:
#define MAX_PLANES FF_ARRAY_ELEMS(((AVPixFmtDescriptor *)0)->comp)
But I have a better suggestion:
#define MAX_SUB 2
double uglarmtable[MAX_SUB + 1][MAX_SUB + 1]
and use uglarmtable[hsub][vsub]. That way, for YUVA420P for example, the
table will be computed only once for Y and A and once for U and V.
The assert is still needed with that solution, though.
I don't understand this. Please provide a complete example, or it stays
as it is. - and could of course be optimized later.
+ if (s->mode == MODE_UGLARM) {
No need to test, we can free anyway.
But why should the for loop run in xy mode and check "planes count"
times to free the memory? The code without the "if" also looks to me
more like this is not checked by mistake.
@All: Opinions?
[Carl Eugen] While there, please don't use sizeof(type) but sizeof(variable),
same below.
Hope that the code is correct like this?
s->uglarmtable[plane] =
av_malloc_array((logo_w - 1) * (logo_h - 1),
sizeof(s->uglarmtable[plane]));
Regards,
Uwe
>From 001e57532567de410ecfa860df99610620dcd385 Mon Sep 17 00:00:00 2001
From: breaker27 <m...@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 | 182 ++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 205 insertions(+), 5 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..45f2f9cd3f 100644
--- a/libavfilter/vf_delogo.c
+++ b/libavfilter/vf_delogo.c
@@ -2,6 +2,7 @@
* Copyright (c) 2002 Jindrich Makovicka <makov...@gmail.com>
* Copyright (c) 2011 Stefano Sabatini
* Copyright (c) 2013, 2015 Jean Delvare <jdelv...@suse.com>
+ * Copyright (c) 2018, 2019 Uwe Freese <m...@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 +162,125 @@ static void apply_delogo(uint8_t *dst, int dst_linesize,
dst += dst_linesize;
src += src_linesize;
}
+ } else {
+ int bx, by;
+ double interpd;
+
+ 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;
+ }
+
+ interpd = 0;
+
+ for (bx = 0; bx < logo_w; bx++) {
+ interpd += topleft[bx] *
+ uglarmtable[abs(bx - x) + y * (logo_w - 1)];
+ interpd += botleft[bx] *
+ uglarmtable[abs(bx - x) + (logo_h - y - 1) * (logo_w - 1)];
+ }
+
+ for (by = 1; by < logo_h - 1; by++) {
+ interpd += topleft[by * src_linesize] *
+ uglarmtable[x + abs(by - y) * (logo_w - 1)];
+ interpd += topleft[by * src_linesize + (logo_w - 1)] *
+ uglarmtable[logo_w - x - 1 + abs(by - y) * (logo_w - 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;
+ 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(sqrt(x * x * aspect * aspect + y * y), exponent);
+ 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_PLANES 10
+
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_PLANES], *uglarmweightsum[MAX_PLANES];
+} DelogoContext;
#define OFFSET(x) offsetof(DelogoContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
@@ -171,6 +295,10 @@ 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 +343,8 @@ 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 +354,18 @@ static av_cold int init(AVFilterContext *ctx)
return 0;
}
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ DelogoContext *s = ctx->priv;
+
+ if (s->mode == MODE_UGLARM) {
+ for (int plane = 0; plane < MAX_PLANES; plane++) {
+ av_freep(&s->uglarmtable[plane]);
+ av_freep(&s->uglarmweightsum[plane]);
+ }
+ }
+}
+
static int config_input(AVFilterLink *inlink)
{
DelogoContext *s = inlink->dst->priv;
@@ -237,6 +377,32 @@ static int config_input(AVFilterLink *inlink)
return AVERROR(EINVAL);
}
+ /* Init lookup tables once */
+ if (s->mode == MODE_UGLARM) {
+ /* 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);
+
+ if (!s->uglarmtable[plane]) {
+ s->uglarmtable[plane] =
+ av_malloc_array((logo_w - 1) * (logo_h - 1), sizeof(s->uglarmtable[plane]));
+
+ if (!s->uglarmtable[plane])
+ return AVERROR(ENOMEM);
+
+ s->uglarmweightsum[plane] =
+ av_malloc_array((logo_w - 2) * (logo_h - 2), sizeof(s->uglarmweightsum[plane]));
+
+ if (!s->uglarmweightsum[plane])
+ return AVERROR(ENOMEM);
+
+ calc_uglarm_tables(s->uglarmtable[plane],
+ s->uglarmweightsum[plane],
+ sar, logo_w, logo_h, s->exponent);
+ }
+ }
+
return 0;
}
@@ -270,6 +436,9 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
if (!sar.num)
sar.num = sar.den = 1;
+ if (s->mode == MODE_UGLARM)
+ av_assert0(desc->nb_components <= MAX_PLANES);
+
for (plane = 0; plane < desc->nb_components; plane++) {
int hsub = plane == 1 || plane == 2 ? hsub0 : 0;
int vsub = plane == 1 || plane == 2 ? vsub0 : 0;
@@ -284,6 +453,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
AV_CEIL_RSHIFT(s->w + (s->x & ((1<<hsub)-1)), hsub),
AV_CEIL_RSHIFT(s->h + (s->y & ((1<<vsub)-1)), vsub),
s->band>>FFMIN(hsub, vsub),
+ s->uglarmtable[plane],
+ s->uglarmweightsum[plane],
s->show, direct);
}
@@ -317,6 +488,7 @@ 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
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