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lavfi/crop: add support to option parsing

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Also fix documentation accordingly.
pull/8/head
Stefano Sabatini 12 years ago
parent 2b643855e0
commit 1e5492ffe6
3 changed files with 75 additions and 44 deletions
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  1. 48
      doc/filters.texi
  2. 2
      libavfilter/version.h
  3. 69
      libavfilter/vf_crop.c

48
doc/filters.texi
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@ -1518,11 +1518,40 @@ testing purposes.
@section crop
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}
Crop the input video.
The @var{keep_aspect} parameter is optional, if specified and set to a
non-zero value will force the output display aspect ratio to be the
same of the input, by changing the output sample aspect ratio.
This filter accepts a list of @var{key}=@var{value} pairs as argument,
separated by ':'. If the key of the first options is omitted, the
arguments are interpreted according to the syntax
@var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}.
A description of the accepted options follows:
@table @option
@item w, out_w
Set the crop area width. It defaults to @code{iw}.
This expression is evaluated only once during the filter
configuration.
@item h, out_h
Set the crop area width. It defaults to @code{ih}.
This expression is evaluated only once during the filter
configuration.
@item x
Set the expression for the x top-left coordinate of the cropped area.
It defaults to @code{(in_w-out_w)/2}.
This expression is evaluated per-frame.
@item y
Set the expression for the y top-left coordinate of the cropped area.
It defaults to @code{(in_h-out_h)/2}.
This expression is evaluated per-frame.
@item keep_aspect
If set to 1 will force the output display aspect ratio
to be the same of the input, by changing the output sample aspect
ratio. It defaults to 0.
@end table
The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
expressions containing the following constants:
@ -1568,13 +1597,6 @@ 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
@ -1585,10 +1607,6 @@ 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}.

2
libavfilter/version.h
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@ -30,7 +30,7 @@
#define LIBAVFILTER_VERSION_MAJOR 3
#define LIBAVFILTER_VERSION_MINOR 27
#define LIBAVFILTER_VERSION_MICRO 101
#define LIBAVFILTER_VERSION_MICRO 102
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \

69
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[] = {
"in_w", "iw", ///< width of the input video
@ -75,6 +76,7 @@ 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
@ -85,11 +87,44 @@ 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, *w_expr, *h_expr;
AVExpr *x_pexpr, *y_pexpr; /* parsed expressions for x and y */
double var_values[VAR_VARS_NB];
} CropContext;
#define OFFSET(x) offsetof(CropContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
static const AVOption crop_options[] = {
{ "x", "set the x crop area expression", OFFSET(x_expr), AV_OPT_TYPE_STRING, {.str = "(in_w-out_w)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "y", "set the y crop area expression", OFFSET(y_expr), AV_OPT_TYPE_STRING, {.str = "(in_h-out_h)/2"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "out_w", "set the width crop area expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "w", "set the width crop area expression", OFFSET(w_expr), AV_OPT_TYPE_STRING, {.str = "iw"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "out_h", "set the height crop area expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "h", "set the height crop area expression", OFFSET(h_expr), AV_OPT_TYPE_STRING, {.str = "ih"}, CHAR_MIN, CHAR_MAX, FLAGS },
{ "keep_aspect", "force packed RGB in input and output", OFFSET(keep_aspect), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS },
{NULL}
};
AVFILTER_DEFINE_CLASS(crop);
static av_cold int init(AVFilterContext *ctx, const char *args)
{
CropContext *crop = ctx->priv;
static const char *shorthand[] = { "w", "h", "x", "y", "keep_aspect", NULL };
crop->class = &crop_class;
av_opt_set_defaults(crop);
return av_opt_set_from_string(crop, args, shorthand, "=", ":");
}
static av_cold void uninit(AVFilterContext *ctx)
{
CropContext *crop = ctx->priv;
av_opt_free(crop);
}
static int query_formats(AVFilterContext *ctx)
{
static const enum AVPixelFormat pix_fmts[] = {
@ -123,29 +158,6 @@ 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[^:]:%d", crop->ow_expr, crop->oh_expr, crop->x_expr, crop->y_expr, &crop->keep_aspect);
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
CropContext *crop = ctx->priv;
av_expr_free(crop->x_pexpr); crop->x_pexpr = NULL;
av_expr_free(crop->y_pexpr); crop->y_pexpr = NULL;
}
static inline int normalize_double(int *n, double d)
{
int ret = 0;
@ -189,16 +201,16 @@ static int config_input(AVFilterLink *link)
crop->hsub = pix_desc->log2_chroma_w;
crop->vsub = pix_desc->log2_chroma_h;
if ((ret = av_expr_parse_and_eval(&res, (expr = crop->ow_expr),
if ((ret = av_expr_parse_and_eval(&res, (expr = crop->w_expr),
var_names, crop->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = res;
if ((ret = av_expr_parse_and_eval(&res, (expr = crop->oh_expr),
if ((ret = av_expr_parse_and_eval(&res, (expr = crop->h_expr),
var_names, crop->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
crop->var_values[VAR_OUT_H] = crop->var_values[VAR_OH] = res;
/* evaluate again ow as it may depend on oh */
if ((ret = av_expr_parse_and_eval(&res, (expr = crop->ow_expr),
if ((ret = av_expr_parse_and_eval(&res, (expr = crop->w_expr),
var_names, crop->var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail_expr;
crop->var_values[VAR_OUT_W] = crop->var_values[VAR_OW] = res;
@ -207,7 +219,7 @@ static int config_input(AVFilterLink *link)
av_log(ctx, AV_LOG_ERROR,
"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);
crop->w_expr, crop->h_expr);
return AVERROR(EINVAL);
}
crop->w &= ~((1 << crop->hsub) - 1);
@ -348,4 +360,5 @@ AVFilter avfilter_vf_crop = {
.inputs = avfilter_vf_crop_inputs,
.outputs = avfilter_vf_crop_outputs,
.priv_class = &crop_class,
};

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