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vf_crop: switch to an AVOptions-based system.

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pull/21/head
Anton Khirnov 12 years ago
parent 51def31dbe
commit fba0156af7
2 changed files with 50 additions and 26 deletions
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  1. 36
      doc/filters.texi
  2. 40
      libavfilter/vf_crop.c

36
doc/filters.texi
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@ -623,7 +623,25 @@ testing purposes.
@section crop
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
Crop the input video to given dimensions.
This filter accepts the following options:
@table @option
@item out_w
Width of the output video.
@item out_h
Height of the output video.
@item x
Horizontal position, in the input video, of the left edge of the output video.
@item y
Vertical position, in the input video, of the top edge of the output video.
@end table
The parameters are expressions containing the following constants:
@ -683,34 +701,34 @@ for @var{y} may depend on @var{x}.
Follow some examples:
@example
# crop the central input area with size 100x100
crop=100:100
crop=out_w=100:out_h=100
# crop the central input area with size 2/3 of the input video
"crop=2/3*in_w:2/3*in_h"
"crop=out_w=2/3*in_w:out_h=2/3*in_h"
# crop the input video central square
crop=in_h
crop=out_w=in_h
# delimit the rectangle with the top-left corner placed at position
# 100:100 and the right-bottom corner corresponding to the right-bottom
# corner of the input image.
crop=in_w-100:in_h-100:100:100
crop=out_w=in_w-100:out_h=in_h-100:x=100:y=100
# crop 10 pixels from the left and right borders, and 20 pixels from
# the top and bottom borders
"crop=in_w-2*10:in_h-2*20"
"crop=out_w=in_w-2*10:out_h=in_h-2*20"
# keep only the bottom right quarter of the input image
"crop=in_w/2:in_h/2:in_w/2:in_h/2"
"crop=out_w=in_w/2:out_h=in_h/2:x=in_w/2:y=in_h/2"
# crop height for getting Greek harmony
"crop=in_w:1/PHI*in_w"
"crop=out_w=in_w:out_h=1/PHI*in_w"
# trembling effect
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)"
# erratic camera effect depending on timestamp
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
"crop=out_w=in_w/2:out_h=in_h/2:x=(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):y=(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
# set x depending on the value of y
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"

40
libavfilter/vf_crop.c
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@ -37,6 +37,7 @@
#include "libavutil/libm.h"
#include "libavutil/imgutils.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
static const char *const var_names[] = {
"E",
@ -70,6 +71,7 @@ enum var_name {
};
typedef struct {
const AVClass *class;
int x; ///< x offset of the non-cropped area with respect to the input area
int y; ///< y offset of the non-cropped area with respect to the input area
int w; ///< width of the cropped area
@ -77,7 +79,7 @@ typedef struct {
int max_step[4]; ///< max pixel step for each plane, expressed as a number of bytes
int hsub, vsub; ///< chroma subsampling
char x_expr[256], y_expr[256], ow_expr[256], oh_expr[256];
char *x_expr, *y_expr, *ow_expr, *oh_expr;
AVExpr *x_pexpr, *y_pexpr; /* parsed expressions for x and y */
double var_values[VAR_VARS_NB];
} CropContext;
@ -115,21 +117,6 @@ static int query_formats(AVFilterContext *ctx)
return 0;
}
static av_cold int init(AVFilterContext *ctx, const char *args)
{
CropContext *crop = ctx->priv;
av_strlcpy(crop->ow_expr, "iw", sizeof(crop->ow_expr));
av_strlcpy(crop->oh_expr, "ih", sizeof(crop->oh_expr));
av_strlcpy(crop->x_expr, "(in_w-out_w)/2", sizeof(crop->x_expr));
av_strlcpy(crop->y_expr, "(in_h-out_h)/2", sizeof(crop->y_expr));
if (args)
sscanf(args, "%255[^:]:%255[^:]:%255[^:]:%255[^:]", crop->ow_expr, crop->oh_expr, crop->x_expr, crop->y_expr);
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
CropContext *crop = ctx->priv;
@ -294,6 +281,25 @@ static int filter_frame(AVFilterLink *link, AVFrame *frame)
return ff_filter_frame(link->dst->outputs[0], frame);
}
#define OFFSET(x) offsetof(CropContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM
static const AVOption options[] = {
{ "out_w", "Output video width", OFFSET(ow_expr), AV_OPT_TYPE_STRING, { .str = "iw" }, .flags = FLAGS },
{ "out_h", "Output video height", OFFSET(oh_expr), AV_OPT_TYPE_STRING, { .str = "ih" }, .flags = FLAGS },
{ "x", "Horizontal position in the input video of the left edge of the cropped output video",
OFFSET(x_expr), AV_OPT_TYPE_STRING, { .str = "(in_w - out_w) / 2" }, .flags = FLAGS },
{ "y", "Vertical position in the input video of the top edge of the cropped output video",
OFFSET(y_expr), AV_OPT_TYPE_STRING, { .str = "(in_h - out_h) / 2" }, .flags = FLAGS },
{ NULL },
};
static const AVClass crop_class = {
.class_name = "crop",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static const AVFilterPad avfilter_vf_crop_inputs[] = {
{
.name = "default",
@ -319,9 +325,9 @@ AVFilter avfilter_vf_crop = {
.description = NULL_IF_CONFIG_SMALL("Crop the input video to width:height:x:y."),
.priv_size = sizeof(CropContext),
.priv_class = &crop_class,
.query_formats = query_formats,
.init = init,
.uninit = uninit,
.inputs = avfilter_vf_crop_inputs,

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