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avfilter/vf_geq: allow user to set interpolation method

This commit is contained in:
Paul B Mahol 2019-10-11 18:26:22 +02:00
parent 996ff3fe86
commit 8a0d45a92e
2 changed files with 35 additions and 0 deletions
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8
doc/filters.texi
View File

@ -11019,6 +11019,14 @@ red/green/blue component. Return 0 if there is no such component.
@item alpha(x, y)
Return the value of the pixel at location (@var{x},@var{y}) of the alpha
plane. Return 0 if there is no such plane.
@item interpolation
Set one of interpolation methods:
@table @option
@item nearest, n
@item bilinear, b
@end table
Default is bilinear.
@end table
For functions, if @var{x} and @var{y} are outside the area, the value will be

27
libavfilter/vf_geq.c
View File

@ -33,6 +33,12 @@
#include "libavutil/pixdesc.h"
#include "internal.h"
enum InterpolationMethods {
INTERP_NEAREST,
INTERP_BILINEAR,
NB_INTERP
};
static const char *const var_names[] = { "X", "Y", "W", "H", "N", "SW", "SH", "T", NULL };
enum { VAR_X, VAR_Y, VAR_W, VAR_H, VAR_N, VAR_SW, VAR_SH, VAR_T, VAR_VARS_NB };
@ -46,6 +52,7 @@ typedef struct GEQContext {
double values[VAR_VARS_NB]; ///< expression values
int hsub, vsub; ///< chroma subsampling
int planes; ///< number of planes
int interpolation;
int is_rgb;
int bps;
} GEQContext;
@ -70,6 +77,12 @@ static const AVOption geq_options[] = {
{ "g", "set green expression", OFFSET(expr_str[G]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "blue_expr", "set blue expression", OFFSET(expr_str[B]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "b", "set blue expression", OFFSET(expr_str[B]), AV_OPT_TYPE_STRING, {.str=NULL}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "interpolation","set interpolation method", OFFSET(interpolation), AV_OPT_TYPE_INT, {.i64=INTERP_BILINEAR}, 0, NB_INTERP-1, FLAGS, "interp" },
{ "i", "set interpolation method", OFFSET(interpolation), AV_OPT_TYPE_INT, {.i64=INTERP_BILINEAR}, 0, NB_INTERP-1, FLAGS, "interp" },
{ "nearest", "nearest interpolation", 0, AV_OPT_TYPE_CONST, {.i64=INTERP_NEAREST}, 0, 0, FLAGS, "interp" },
{ "n", "nearest interpolation", 0, AV_OPT_TYPE_CONST, {.i64=INTERP_NEAREST}, 0, 0, FLAGS, "interp" },
{ "bilinear", "bilinear interpolation", 0, AV_OPT_TYPE_CONST, {.i64=INTERP_BILINEAR}, 0, 0, FLAGS, "interp" },
{ "b", "bilinear interpolation", 0, AV_OPT_TYPE_CONST, {.i64=INTERP_BILINEAR}, 0, 0, FLAGS, "interp" },
{NULL},
};
@ -88,6 +101,7 @@ static inline double getpix(void *priv, double x, double y, int plane)
if (!src)
return 0;
if (geq->interpolation == INTERP_BILINEAR) {
xi = x = av_clipd(x, 0, w - 2);
yi = y = av_clipd(y, 0, h - 2);
@ -104,6 +118,19 @@ static inline double getpix(void *priv, double x, double y, int plane)
return (1-y)*((1-x)*src[xi + yi * linesize] + x*src[xi + 1 + yi * linesize])
+ y *((1-x)*src[xi + (yi+1) * linesize] + x*src[xi + 1 + (yi+1) * linesize]);
}
} else {
xi = av_clipd(x, 0, w - 1);
yi = av_clipd(y, 0, h - 1);
if (geq->bps > 8) {
const uint16_t *src16 = (const uint16_t*)src;
linesize /= 2;
return src16[xi + yi * linesize];
} else {
return src[xi + yi * linesize];
}
}
}
//TODO: cubic interpolate