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lavfi/curves: do not automatically insert points at x=0 and x=1

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There is actually a need for the origin and end point not to be defined.
We can not automatically insert them with the y value of the first and
last point as it will influence the curves in a wrong way.

Fixes #5397
This commit is contained in:
Clément Bœsch 2016-07-16 13:46:32 +02:00
parent 783a2568b2
commit 5c14018fc4
3 changed files with 52 additions and 49 deletions
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1
Changelog
View File

@ -7,6 +7,7 @@ version <next>:
- Changed metadata print option to accept general urls
- Alias muxer for Ogg Video (.ogv)
- VP8 in Ogg muxing
- curves filter doesn't automatically insert points at x=0 and x=1 anymore
version 3.1:

10
doc/filters.texi
View File

@ -5710,10 +5710,6 @@ strictly increasing over the x-axis, and their @var{x} and @var{y} values must
be in the @var{[0;1]} interval. If the computed curves happened to go outside
the vector spaces, the values will be clipped accordingly.
If there is no key point defined in @code{x=0}, the filter will automatically
insert a @var{(0;0)} point. In the same way, if there is no key point defined
in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
The filter accepts the following options:
@table @option
@ -5765,13 +5761,13 @@ defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
@item
Increase slightly the middle level of blue:
@example
curves=blue='0.5/0.58'
curves=blue='0/0 0.5/0.58 1/1'
@end example
@item
Vintage effect:
@example
curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
curves=r='0/0.11 .42/.51 1/0.95':g='0/0 0.50/0.48 1/1':b='0/0.22 .49/.44 1/0.8'
@end example
Here we obtain the following coordinates for each components:
@table @var
@ -5798,7 +5794,7 @@ curves=vintage
@item
Use a Photoshop preset and redefine the points of the green component:
@example
curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
curves=psfile='MyCurvesPresets/purple.acv':green='0/0 0.45/0.53 1/1'
@end example
@end itemize

90
libavfilter/vf_curves.c
View File

@ -110,25 +110,25 @@ static const struct {
const char *master;
} curves_presets[] = {
[PRESET_COLOR_NEGATIVE] = {
"0/1 0.129/1 0.466/0.498 0.725/0 1/0",
"0/1 0.109/1 0.301/0.498 0.517/0 1/0",
"0/1 0.098/1 0.235/0.498 0.423/0 1/0",
"0.129/1 0.466/0.498 0.725/0",
"0.109/1 0.301/0.498 0.517/0",
"0.098/1 0.235/0.498 0.423/0",
},
[PRESET_CROSS_PROCESS] = {
"0.25/0.156 0.501/0.501 0.686/0.745",
"0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
"0.231/0.094 0.709/0.874",
"0/0 0.25/0.156 0.501/0.501 0.686/0.745 1/1",
"0/0 0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
"0/0 0.231/0.094 0.709/0.874 1/1",
},
[PRESET_DARKER] = { .master = "0.5/0.4" },
[PRESET_INCREASE_CONTRAST] = { .master = "0.149/0.066 0.831/0.905 0.905/0.98" },
[PRESET_LIGHTER] = { .master = "0.4/0.5" },
[PRESET_LINEAR_CONTRAST] = { .master = "0.305/0.286 0.694/0.713" },
[PRESET_MEDIUM_CONTRAST] = { .master = "0.286/0.219 0.639/0.643" },
[PRESET_DARKER] = { .master = "0/0 0.5/0.4 1/1" },
[PRESET_INCREASE_CONTRAST] = { .master = "0/0 0.149/0.066 0.831/0.905 0.905/0.98 1/1" },
[PRESET_LIGHTER] = { .master = "0/0 0.4/0.5 1/1" },
[PRESET_LINEAR_CONTRAST] = { .master = "0/0 0.305/0.286 0.694/0.713 1/1" },
[PRESET_MEDIUM_CONTRAST] = { .master = "0/0 0.286/0.219 0.639/0.643 1/1" },
[PRESET_NEGATIVE] = { .master = "0/1 1/0" },
[PRESET_STRONG_CONTRAST] = { .master = "0.301/0.196 0.592/0.6 0.686/0.737" },
[PRESET_STRONG_CONTRAST] = { .master = "0/0 0.301/0.196 0.592/0.6 0.686/0.737 1/1" },
[PRESET_VINTAGE] = {
"0/0.11 0.42/0.51 1/0.95",
"0.50/0.48",
"0/0 0.50/0.48 1/1",
"0/0.22 0.49/0.44 1/0.8",
}
};
@ -177,28 +177,11 @@ static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, cons
last = point;
}
/* auto insert first key point if missing at x=0 */
if (!*points) {
last = make_point(0, 0, NULL);
if (!last)
return AVERROR(ENOMEM);
last->x = last->y = 0;
*points = last;
} else if ((*points)->x != 0.) {
struct keypoint *newfirst = make_point(0, 0, *points);
if (!newfirst)
return AVERROR(ENOMEM);
*points = newfirst;
}
av_assert0(last);
/* auto insert last key point if missing at x=1 */
if (last->x != 1.) {
struct keypoint *point = make_point(1, 1, NULL);
if (!point)
return AVERROR(ENOMEM);
last->next = point;
if (*points && !(*points)->next) {
av_log(ctx, AV_LOG_WARNING, "Only one point (at (%f;%f)) is defined, "
"this is unlikely to behave as you expect. You probably want"
"at least 2 points.",
(*points)->x, (*points)->y);
}
return 0;
@ -222,14 +205,28 @@ static int get_nb_points(const struct keypoint *d)
static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *points)
{
int i, ret = 0;
const struct keypoint *point;
const struct keypoint *point = points;
double xprev = 0;
double (*matrix)[3];
double *h, *r;
int n = get_nb_points(points); // number of splines
double (*matrix)[3] = av_calloc(n, sizeof(*matrix));
double *h = av_malloc((n - 1) * sizeof(*h));
double *r = av_calloc(n, sizeof(*r));
if (n == 0) {
for (i = 0; i < 256; i++)
y[i] = i;
return 0;
}
if (n == 1) {
for (i = 0; i < 256; i++)
y[i] = av_clip_uint8(point->y * 255);
return 0;
}
matrix = av_calloc(n, sizeof(*matrix));
h = av_malloc((n - 1) * sizeof(*h));
r = av_calloc(n, sizeof(*r));
if (!matrix || !h || !r) {
ret = AVERROR(ENOMEM);
@ -277,9 +274,14 @@ static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *
for (i = n - 2; i >= 0; i--)
r[i] = r[i] - matrix[i][AD] * r[i + 1];
/* compute the graph with x=[0..255] */
i = 0;
point = points;
/* left padding */
for (i = 0; i < (int)(point->x * 255); i++)
y[i] = av_clip_uint8(point->y * 255);
/* compute the graph with x=[x0..xN] */
i = 0;
av_assert0(point->next); // always at least 2 key points
while (point->next) {
double yc = point->y;
@ -300,7 +302,7 @@ static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *
for (x = x_start; x <= x_end; x++) {
double xx = (x - x_start) * 1/255.;
double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;
y[x] = av_clipf(yy, 0, 1) * 255;
y[x] = av_clip_uint8(yy * 255);
av_log(ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);
}
@ -308,6 +310,10 @@ static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *
i++;
}
/* right padding */
for (i = (int)(point->x * 255); i <= 255; i++)
y[i] = av_clip_uint8(point->y * 255);
end:
av_free(matrix);
av_free(h);