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Make the crop filters accept parametric expressions.

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Originally committed as revision 25185 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Stefano Sabatini 2010-09-25 01:18:43 +00:00
parent 2bc05d3547
commit 75b67a8a99
5 changed files with 258 additions and 50 deletions
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1
Changelog
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@ -38,6 +38,7 @@ version <next>:
- ocv_smooth filter
- frei0r wrapper filter
- change crop filter syntax to width:height:x:y
- make the crop filter accept parametric expressions
version 0.6:

117
doc/filters.texi
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@ -26,35 +26,102 @@ Below is a description of the currently available video filters.
@section crop
Crop the input video to @var{width}:@var{height}:@var{x}:@var{y}.
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
The parameters are expressions containing the following constants:
@table @option
@item E, PI, PHI
the corresponding mathematical approximated values for e
(euler number), pi (greek PI), PHI (golden ratio)
@item x, y
the computed values for @var{x} and @var{y}. They are evaluated for
each new frame.
@item in_w, in_h
the input width and heigth
@item iw, ih
same as @var{in_w} and @var{in_h}
@item out_w, out_h
the output (cropped) width and heigth
@item ow, oh
same as @var{out_w} and @var{out_h}
@item n
the number of input frame, starting from 0
@item pos
the position in the file of the input frame, NAN if unknown
@item t
timestamp expressed in seconds, NAN if the input timestamp is unknown
@end table
The @var{out_w} and @var{out_h} parameters specify the expressions for
the width and height of the output (cropped) video. They are
evaluated just at the configuration of the filter.
The default value of @var{out_w} is "in_w", and the default value of
@var{out_h} is "in_h".
The expression for @var{out_w} may depend on the value of @var{out_h},
and the expression for @var{out_h} may depend on @var{out_w}, but they
cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
evaluated after @var{out_w} and @var{out_h}.
The @var{x} and @var{y} parameters specify the expressions for the
position of the top-left corner of the output (non-cropped) area. They
are evaluated for each frame. If the evaluated value is not valid, it
is approximated to the nearest valid value.
The default value of @var{x} is "(in_w-out_w)/2", and the default
value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
the center of the input image.
The expression for @var{x} may depend on @var{y}, and the expression
for @var{y} may depend on @var{x}.
Follow some examples:
@example
./ffmpeg -i in.avi -vf "crop=0:240:0:0" out.avi
# crop the central input area with size 100x100
crop=100:100
# crop the central input area with size 2/3 of the input video
"crop=2/3*in_w:2/3*in_h"
# crop the input video central square
crop=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 10 pixels from the lefth and right borders, and 20 pixels from
# the top and bottom borders
"crop=in_w-2*10: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 height for getting Greek harmony
"crop=in_w: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 and position
"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)"
# set x depending on the value of y
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
@end example
The @var{width} and @var{height} parameters specify the width and height
of the output (non-cropped) area.
A value of 0 is interpreted as the maximum possible size contained in
the area delimited by the top-left corner at position x:y.
@var{x} and @var{y} specify the position of the top-left corner of the
output (non-cropped) area.
The default value of @var{x} and @var{y} is 0.
For example the parameters:
@example
"crop=0:0:100:100"
@end example
will 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.
The default value of @var{width} and @var{height} is 0.
@section fifo
Buffer input images and send them when they are requested.

2
libavfilter/avfilter.h
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@ -25,7 +25,7 @@
#include "libavutil/avutil.h"
#define LIBAVFILTER_VERSION_MAJOR 1
#define LIBAVFILTER_VERSION_MINOR 41
#define LIBAVFILTER_VERSION_MINOR 42
#define LIBAVFILTER_VERSION_MICRO 0
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

178
libavfilter/vf_crop.c
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@ -24,8 +24,43 @@
*/
#include "avfilter.h"
#include "libavutil/eval.h"
#include "libavutil/avstring.h"
#include "libavutil/libm.h"
#include "libavcore/imgutils.h"
static const char *var_names[] = {
"E",
"PHI",
"PI",
"in_w", "iw", ///< width of the input video
"in_h", "ih", ///< height of the input video
"out_w", "ow", ///< width of the cropped video
"out_h", "oh", ///< height of the cropped video
"x",
"y",
"n", ///< number of frame
"pos", ///< position in the file
"t", ///< timestamp expressed in seconds
NULL
};
enum var_name {
E,
PHI,
PI,
IN_W, IW,
IN_H, IH,
OUT_W, OW,
OUT_H, OH,
X,
Y,
N,
POS,
T,
VARS_NB
};
typedef struct {
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
@ -34,6 +69,9 @@ 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];
AVExpr *x_pexpr, *y_pexpr; /* parsed expressions for x and y */
double var_values[VARS_NB];
} CropContext;
static int query_formats(AVFilterContext *ctx)
@ -72,44 +110,114 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
{
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, "%d:%d:%d:%d", &crop->w, &crop->h, &crop->x, &crop->y);
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;
av_free_expr(crop->x_pexpr); crop->x_pexpr = NULL;
av_free_expr(crop->y_pexpr); crop->y_pexpr = NULL;
}
static inline int normalize_double(int *n, double d)
{
int ret = 0;
if (isnan(d)) {
ret = AVERROR(EINVAL);
} else if (d > INT_MAX || d < INT_MIN) {
*n = d > INT_MAX ? INT_MAX : INT_MIN;
ret = AVERROR(EINVAL);
} else
*n = round(d);
return ret;
}
static int config_input(AVFilterLink *link)
{
AVFilterContext *ctx = link->dst;
CropContext *crop = ctx->priv;
const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[link->format];
int ret;
const char *expr;
double res;
crop->var_values[E] = M_E;
crop->var_values[PHI] = M_PHI;
crop->var_values[PI] = M_PI;
crop->var_values[IN_W] = crop->var_values[IW] = ctx->inputs[0]->w;
crop->var_values[IN_H] = crop->var_values[IH] = ctx->inputs[0]->h;
crop->var_values[X] = NAN;
crop->var_values[Y] = NAN;
crop->var_values[OUT_W] = crop->var_values[OW] = NAN;
crop->var_values[OUT_H] = crop->var_values[OH] = NAN;
crop->var_values[N] = 0;
crop->var_values[T] = NAN;
crop->var_values[POS] = NAN;
av_image_fill_max_pixsteps(crop->max_step, NULL, pix_desc);
crop->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;
crop->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;
if (crop->w == 0)
crop->w = link->w - crop->x;
if (crop->h == 0)
crop->h = link->h - crop->y;
crop->x &= ~((1 << crop->hsub) - 1);
crop->y &= ~((1 << crop->vsub) - 1);
av_log(link->dst, AV_LOG_INFO, "w:%d h:%d x:%d y:%d\n",
crop->w, crop->h, crop->x, crop->y);
if (crop->x < 0 || crop->y < 0 ||
crop->w <= 0 || crop->h <= 0 ||
(unsigned)crop->x + (unsigned)crop->w > link->w ||
(unsigned)crop->y + (unsigned)crop->h > link->h) {
if ((ret = av_parse_and_eval_expr(&res, (expr = crop->ow_expr),
var_names, crop->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
crop->var_values[OUT_W] = crop->var_values[OW] = res;
if ((ret = av_parse_and_eval_expr(&res, (expr = crop->oh_expr),
var_names, crop->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
crop->var_values[OUT_H] = crop->var_values[OH] = res;
/* evaluate again ow as it may depend on oh */
if ((ret = av_parse_and_eval_expr(&res, (expr = crop->ow_expr),
var_names, crop->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
crop->var_values[OUT_W] = crop->var_values[OW] = res;
if (normalize_double(&crop->w, crop->var_values[OUT_W]) < 0 ||
normalize_double(&crop->h, crop->var_values[OUT_H]) < 0) {
av_log(ctx, AV_LOG_ERROR,
"Output area %d:%d:%d:%d not within the input area 0:0:%d:%d or zero-sized\n",
crop->x, crop->y, crop->w, crop->h, link->w, link->h);
"Too big value or invalid expression for out_w/ow or out_h/oh. "
"Maybe the expression for out_w:'%s' or for out_h:'%s' is self-referencing.\n",
crop->ow_expr, crop->oh_expr);
return AVERROR(EINVAL);
}
crop->w &= ~((1 << crop->hsub) - 1);
crop->h &= ~((1 << crop->vsub) - 1);
if ((ret = av_parse_expr(&crop->x_pexpr, crop->x_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0 ||
(ret = av_parse_expr(&crop->y_pexpr, crop->y_expr, var_names,
NULL, NULL, NULL, NULL, 0, ctx)) < 0)
return AVERROR(EINVAL);
if (crop->w <= 0 || crop->h <= 0 ||
crop->w > link->w || crop->h > link->h) {
av_log(ctx, AV_LOG_ERROR,
"Invalid too big or non positive size for width '%d' or height '%d'\n",
crop->w, crop->h);
return AVERROR(EINVAL);
}
/* set default, required in the case the first computed value for x/y is NAN */
crop->x = (link->w - crop->w) / 2;
crop->y = (link->h - crop->h) / 2;
crop->x &= ~((1 << crop->hsub) - 1);
crop->y &= ~((1 << crop->vsub) - 1);
return 0;
fail_expr:
av_log(NULL, AV_LOG_ERROR, "Error when evaluating the expression '%s'\n", expr);
return ret;
}
static int config_output(AVFilterLink *link)
@ -124,13 +232,35 @@ static int config_output(AVFilterLink *link)
static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
{
CropContext *crop = link->dst->priv;
AVFilterContext *ctx = link->dst;
CropContext *crop = ctx->priv;
AVFilterBufferRef *ref2 = avfilter_ref_buffer(picref, ~0);
int i;
picref->video->w = crop->w;
picref->video->h = crop->h;
/* FIXME: when the TB will be settable */
crop->var_values[T] = picref->pts == AV_NOPTS_VALUE ? NAN : (double)picref->pts / AV_TIME_BASE;
crop->var_values[POS] = picref->pos == -1 ? NAN : picref->pos;
crop->var_values[X] = av_eval_expr(crop->x_pexpr, crop->var_values, NULL);
crop->var_values[Y] = av_eval_expr(crop->y_pexpr, crop->var_values, NULL);
crop->var_values[X] = av_eval_expr(crop->x_pexpr, crop->var_values, NULL);
normalize_double(&crop->x, crop->var_values[X]);
normalize_double(&crop->y, crop->var_values[Y]);
if (crop->x < 0) crop->x = 0;
if (crop->y < 0) crop->y = 0;
if ((unsigned)crop->x + (unsigned)crop->w > link->w) crop->x = link->w - crop->w;
if ((unsigned)crop->y + (unsigned)crop->h > link->h) crop->y = link->h - crop->h;
crop->x &= ~((1 << crop->hsub) - 1);
crop->y &= ~((1 << crop->vsub) - 1);
av_log(ctx, AV_LOG_DEBUG,
"n:%d t:%f x:%d y:%d x+w:%d y+h:%d\n",
(int)crop->var_values[N], crop->var_values[T], crop->x, crop->y, crop->x+crop->w, crop->y+crop->h);
ref2->data[0] += crop->y * ref2->linesize[0];
ref2->data[0] += crop->x * crop->max_step[0];
@ -170,6 +300,14 @@ static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
avfilter_draw_slice(ctx->outputs[0], y - crop->y, h, slice_dir);
}
static void end_frame(AVFilterLink *link)
{
CropContext *crop = link->dst->priv;
crop->var_values[N] += 1.0;
avfilter_end_frame(link->dst->outputs[0]);
}
AVFilter avfilter_vf_crop = {
.name = "crop",
.description = NULL_IF_CONFIG_SMALL("Crop the input video to width:height:x:y."),
@ -178,11 +316,13 @@ AVFilter avfilter_vf_crop = {
.query_formats = query_formats,
.init = init,
.uninit = uninit,
.inputs = (AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.start_frame = start_frame,
.draw_slice = draw_slice,
.end_frame = end_frame,
.get_video_buffer = avfilter_null_get_video_buffer,
.config_props = config_input, },
{ .name = NULL}},

10
tests/lavfi-regression.sh
View File

@ -22,15 +22,15 @@ do_lavfi() {
fi
}
do_lavfi "crop" "crop=0:0:100:100"
do_lavfi "crop_scale" "crop=0:0:100:100,scale=400:-1"
do_lavfi "crop_scale_vflip" "null,null,crop=0:0:200:200,crop=0:0:20:20,scale=200:200,scale=250:250,vflip,vflip,null,scale=200:200,crop=0:0:100:100,vflip,scale=200:200,null,vflip,crop=0:0:100:100,null"
do_lavfi "crop_vflip" "crop=0:0:100:100,vflip"
do_lavfi "crop" "crop=iw-100:ih-100:100:100"
do_lavfi "crop_scale" "crop=iw-100:ih-100:100:100,scale=400:-1"
do_lavfi "crop_scale_vflip" "null,null,crop=iw-200:ih-200:200:200,crop=iw-20:ih-20:20:20,scale=200:200,scale=250:250,vflip,vflip,null,scale=200:200,crop=iw-100:ih-100:100:100,vflip,scale=200:200,null,vflip,crop=iw-100:ih-100:100:100,null"
do_lavfi "crop_vflip" "crop=iw-100:ih-100:100:100,vflip"
do_lavfi "null" "null"
do_lavfi "scale200" "scale=200:200"
do_lavfi "scale500" "scale=500:500"
do_lavfi "vflip" "vflip"
do_lavfi "vflip_crop" "vflip,crop=0:0:100:100"
do_lavfi "vflip_crop" "vflip,crop=iw-100:ih-100:100:100"
do_lavfi "vflip_vflip" "vflip,vflip"
do_lavfi_pixfmts(){