lavfi/curves: do not automatically insert points at x=0 and x=1
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
parent
783a2568b2
commit
5c14018fc4
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@ -7,6 +7,7 @@ version <next>:
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- Changed metadata print option to accept general urls
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- Alias muxer for Ogg Video (.ogv)
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- VP8 in Ogg muxing
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- curves filter doesn't automatically insert points at x=0 and x=1 anymore
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version 3.1:
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@ -5710,10 +5710,6 @@ strictly increasing over the x-axis, and their @var{x} and @var{y} values must
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be in the @var{[0;1]} interval. If the computed curves happened to go outside
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the vector spaces, the values will be clipped accordingly.
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If there is no key point defined in @code{x=0}, the filter will automatically
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insert a @var{(0;0)} point. In the same way, if there is no key point defined
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in @code{x=1}, the filter will automatically insert a @var{(1;1)} point.
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The filter accepts the following options:
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@table @option
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@ -5765,13 +5761,13 @@ defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}.
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@item
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Increase slightly the middle level of blue:
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@example
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curves=blue='0.5/0.58'
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curves=blue='0/0 0.5/0.58 1/1'
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@end example
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@item
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Vintage effect:
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@example
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curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8'
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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'
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@end example
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Here we obtain the following coordinates for each components:
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@table @var
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@ -5798,7 +5794,7 @@ curves=vintage
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@item
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Use a Photoshop preset and redefine the points of the green component:
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@example
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curves=psfile='MyCurvesPresets/purple.acv':green='0.45/0.53'
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curves=psfile='MyCurvesPresets/purple.acv':green='0/0 0.45/0.53 1/1'
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@end example
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@end itemize
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@ -110,25 +110,25 @@ static const struct {
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const char *master;
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} curves_presets[] = {
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[PRESET_COLOR_NEGATIVE] = {
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"0/1 0.129/1 0.466/0.498 0.725/0 1/0",
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"0/1 0.109/1 0.301/0.498 0.517/0 1/0",
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"0/1 0.098/1 0.235/0.498 0.423/0 1/0",
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"0.129/1 0.466/0.498 0.725/0",
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"0.109/1 0.301/0.498 0.517/0",
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"0.098/1 0.235/0.498 0.423/0",
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},
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[PRESET_CROSS_PROCESS] = {
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"0.25/0.156 0.501/0.501 0.686/0.745",
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"0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
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"0.231/0.094 0.709/0.874",
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"0/0 0.25/0.156 0.501/0.501 0.686/0.745 1/1",
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"0/0 0.25/0.188 0.38/0.501 0.745/0.815 1/0.815",
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"0/0 0.231/0.094 0.709/0.874 1/1",
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},
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[PRESET_DARKER] = { .master = "0.5/0.4" },
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[PRESET_INCREASE_CONTRAST] = { .master = "0.149/0.066 0.831/0.905 0.905/0.98" },
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[PRESET_LIGHTER] = { .master = "0.4/0.5" },
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[PRESET_LINEAR_CONTRAST] = { .master = "0.305/0.286 0.694/0.713" },
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[PRESET_MEDIUM_CONTRAST] = { .master = "0.286/0.219 0.639/0.643" },
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[PRESET_DARKER] = { .master = "0/0 0.5/0.4 1/1" },
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[PRESET_INCREASE_CONTRAST] = { .master = "0/0 0.149/0.066 0.831/0.905 0.905/0.98 1/1" },
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[PRESET_LIGHTER] = { .master = "0/0 0.4/0.5 1/1" },
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[PRESET_LINEAR_CONTRAST] = { .master = "0/0 0.305/0.286 0.694/0.713 1/1" },
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[PRESET_MEDIUM_CONTRAST] = { .master = "0/0 0.286/0.219 0.639/0.643 1/1" },
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[PRESET_NEGATIVE] = { .master = "0/1 1/0" },
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[PRESET_STRONG_CONTRAST] = { .master = "0.301/0.196 0.592/0.6 0.686/0.737" },
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[PRESET_STRONG_CONTRAST] = { .master = "0/0 0.301/0.196 0.592/0.6 0.686/0.737 1/1" },
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[PRESET_VINTAGE] = {
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"0/0.11 0.42/0.51 1/0.95",
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"0.50/0.48",
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"0/0 0.50/0.48 1/1",
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"0/0.22 0.49/0.44 1/0.8",
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}
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};
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@ -177,28 +177,11 @@ static int parse_points_str(AVFilterContext *ctx, struct keypoint **points, cons
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last = point;
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}
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/* auto insert first key point if missing at x=0 */
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if (!*points) {
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last = make_point(0, 0, NULL);
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if (!last)
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return AVERROR(ENOMEM);
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last->x = last->y = 0;
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*points = last;
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} else if ((*points)->x != 0.) {
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struct keypoint *newfirst = make_point(0, 0, *points);
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if (!newfirst)
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return AVERROR(ENOMEM);
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*points = newfirst;
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}
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av_assert0(last);
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/* auto insert last key point if missing at x=1 */
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if (last->x != 1.) {
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struct keypoint *point = make_point(1, 1, NULL);
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if (!point)
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return AVERROR(ENOMEM);
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last->next = point;
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if (*points && !(*points)->next) {
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av_log(ctx, AV_LOG_WARNING, "Only one point (at (%f;%f)) is defined, "
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"this is unlikely to behave as you expect. You probably want"
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"at least 2 points.",
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(*points)->x, (*points)->y);
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}
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return 0;
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@ -222,14 +205,28 @@ static int get_nb_points(const struct keypoint *d)
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static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *points)
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{
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int i, ret = 0;
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const struct keypoint *point;
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const struct keypoint *point = points;
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double xprev = 0;
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double (*matrix)[3];
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double *h, *r;
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int n = get_nb_points(points); // number of splines
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double (*matrix)[3] = av_calloc(n, sizeof(*matrix));
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double *h = av_malloc((n - 1) * sizeof(*h));
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double *r = av_calloc(n, sizeof(*r));
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if (n == 0) {
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for (i = 0; i < 256; i++)
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y[i] = i;
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return 0;
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}
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if (n == 1) {
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for (i = 0; i < 256; i++)
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y[i] = av_clip_uint8(point->y * 255);
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return 0;
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}
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matrix = av_calloc(n, sizeof(*matrix));
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h = av_malloc((n - 1) * sizeof(*h));
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r = av_calloc(n, sizeof(*r));
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if (!matrix || !h || !r) {
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ret = AVERROR(ENOMEM);
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@ -277,9 +274,14 @@ static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *
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for (i = n - 2; i >= 0; i--)
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r[i] = r[i] - matrix[i][AD] * r[i + 1];
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/* compute the graph with x=[0..255] */
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i = 0;
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point = points;
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/* left padding */
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for (i = 0; i < (int)(point->x * 255); i++)
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y[i] = av_clip_uint8(point->y * 255);
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/* compute the graph with x=[x0..xN] */
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i = 0;
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av_assert0(point->next); // always at least 2 key points
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while (point->next) {
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double yc = point->y;
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@ -300,7 +302,7 @@ static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *
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for (x = x_start; x <= x_end; x++) {
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double xx = (x - x_start) * 1/255.;
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double yy = a + b*xx + c*xx*xx + d*xx*xx*xx;
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y[x] = av_clipf(yy, 0, 1) * 255;
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y[x] = av_clip_uint8(yy * 255);
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av_log(ctx, AV_LOG_DEBUG, "f(%f)=%f -> y[%d]=%d\n", xx, yy, x, y[x]);
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}
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@ -308,6 +310,10 @@ static int interpolate(AVFilterContext *ctx, uint8_t *y, const struct keypoint *
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i++;
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}
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/* right padding */
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for (i = (int)(point->x * 255); i <= 255; i++)
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y[i] = av_clip_uint8(point->y * 255);
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end:
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av_free(matrix);
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av_free(h);
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