mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-23 12:43:46 +02:00
scale: make the filter parametric
Make the filter accept parametric expressions for the output video size. Signed-off-by: Stefano Sabatini <stefano.sabatini-lala@poste.it>
This commit is contained in:
Stefano Sabatini
parent
25601bc564
commit
d496d33d26
@ -1004,13 +1004,33 @@ can be used to test the monowhite pixel format descriptor definition.
|
||||
|
||||
Scale the input video to @var{width}:@var{height} and/or convert the image format.
|
||||
|
||||
For example the command:
|
||||
The parameters @var{width} and @var{height} are expressions containing
|
||||
the following constants:
|
||||
|
||||
@example
|
||||
./ffmpeg -i in.avi -vf "scale=200:100" out.avi
|
||||
@end example
|
||||
@table @option
|
||||
@item E, PI, PHI
|
||||
the corresponding mathematical approximated values for e
|
||||
(euler number), pi (greek PI), phi (golden ratio)
|
||||
|
||||
will scale the input video to a size of 200x100.
|
||||
@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 a
|
||||
input display aspect ratio, same as @var{iw} / @var{ih}
|
||||
|
||||
@item hsub, vsub
|
||||
horizontal and vertical chroma subsample values. For example for the
|
||||
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
||||
@end table
|
||||
|
||||
If the input image format is different from the format requested by
|
||||
the next filter, the scale filter will convert the input to the
|
||||
@ -1025,6 +1045,36 @@ ratio of the input image.
|
||||
|
||||
The default value of @var{width} and @var{height} is 0.
|
||||
|
||||
Some examples follow:
|
||||
@example
|
||||
# scale the input video to a size of 200x100.
|
||||
scale=200:100
|
||||
|
||||
# scale the input to 2x
|
||||
scale=2*iw:2*ih
|
||||
# the above is the same as
|
||||
scale=2*in_w:2*in_h
|
||||
|
||||
# scale the input to half size
|
||||
scale=iw/2:ih/2
|
||||
|
||||
# increase the width, and set the height to the same size
|
||||
scale=3/2*iw:ow
|
||||
|
||||
# seek for Greek harmony
|
||||
scale=iw:1/PHI*iw
|
||||
scale=ih*PHI:ih
|
||||
|
||||
# increase the height, and set the width to 3/2 of the height
|
||||
scale=3/2*oh:3/5*ih
|
||||
|
||||
# increase the size, but make the size a multiple of the chroma
|
||||
scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
|
||||
|
||||
# increase the width to a maximum of 500 pixels, keep the same input aspect ratio
|
||||
scale='min(500\, iw*3/2):-1'
|
||||
@end example
|
||||
|
||||
@anchor{setdar}
|
||||
@section setdar
|
||||
|
||||
|
||||
@ -27,7 +27,7 @@
|
||||
|
||||
#define LIBAVFILTER_VERSION_MAJOR 1
|
||||
#define LIBAVFILTER_VERSION_MINOR 77
|
||||
#define LIBAVFILTER_VERSION_MICRO 0
|
||||
#define LIBAVFILTER_VERSION_MICRO 1
|
||||
|
||||
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
|
||||
LIBAVFILTER_VERSION_MINOR, \
|
||||
|
||||
@ -24,10 +24,40 @@
|
||||
*/
|
||||
|
||||
#include "avfilter.h"
|
||||
#include "libavutil/avstring.h"
|
||||
#include "libavutil/eval.h"
|
||||
#include "libavutil/pixdesc.h"
|
||||
#include "libavutil/avassert.h"
|
||||
#include "libswscale/swscale.h"
|
||||
|
||||
static const char *var_names[] = {
|
||||
"PI",
|
||||
"PHI",
|
||||
"E",
|
||||
"in_w", "iw",
|
||||
"in_h", "ih",
|
||||
"out_w", "ow",
|
||||
"out_h", "oh",
|
||||
"a",
|
||||
"hsub",
|
||||
"vsub",
|
||||
NULL
|
||||
};
|
||||
|
||||
enum var_name {
|
||||
VAR_PI,
|
||||
VAR_PHI,
|
||||
VAR_E,
|
||||
VAR_IN_W, VAR_IW,
|
||||
VAR_IN_H, VAR_IH,
|
||||
VAR_OUT_W, VAR_OW,
|
||||
VAR_OUT_H, VAR_OH,
|
||||
VAR_A,
|
||||
VAR_HSUB,
|
||||
VAR_VSUB,
|
||||
VARS_NB
|
||||
};
|
||||
|
||||
typedef struct {
|
||||
struct SwsContext *sws; ///< software scaler context
|
||||
struct SwsContext *isws[2]; ///< software scaler context for interlaced material
|
||||
@ -44,6 +74,9 @@ typedef struct {
|
||||
int slice_y; ///< top of current output slice
|
||||
int input_is_pal; ///< set to 1 if the input format is paletted
|
||||
int interlaced;
|
||||
|
||||
char w_expr[256]; ///< width expression string
|
||||
char h_expr[256]; ///< height expression string
|
||||
} ScaleContext;
|
||||
|
||||
static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
|
||||
@ -51,9 +84,12 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
|
||||
ScaleContext *scale = ctx->priv;
|
||||
const char *p;
|
||||
|
||||
av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr));
|
||||
av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr));
|
||||
|
||||
scale->flags = SWS_BILINEAR;
|
||||
if (args) {
|
||||
sscanf(args, "%d:%d", &scale->w, &scale->h);
|
||||
sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr);
|
||||
p = strstr(args,"flags=");
|
||||
if (p) scale->flags = strtoul(p+6, NULL, 0);
|
||||
if(strstr(args,"interl=1")){
|
||||
@ -62,14 +98,6 @@ static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
|
||||
scale->interlaced=-1;
|
||||
}
|
||||
|
||||
/* sanity check params */
|
||||
if (scale->w < -1 || scale->h < -1) {
|
||||
av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
|
||||
return AVERROR(EINVAL);
|
||||
}
|
||||
if (scale->w == -1 && scale->h == -1)
|
||||
scale->w = scale->h = 0;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
@ -118,6 +146,48 @@ static int config_props(AVFilterLink *outlink)
|
||||
AVFilterLink *inlink = outlink->src->inputs[0];
|
||||
ScaleContext *scale = ctx->priv;
|
||||
int64_t w, h;
|
||||
double var_values[VARS_NB], res;
|
||||
char *expr;
|
||||
int ret;
|
||||
|
||||
var_values[VAR_PI] = M_PI;
|
||||
var_values[VAR_PHI] = M_PHI;
|
||||
var_values[VAR_E] = M_E;
|
||||
var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w;
|
||||
var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h;
|
||||
var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN;
|
||||
var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN;
|
||||
var_values[VAR_A] = (float) inlink->w / inlink->h;
|
||||
var_values[VAR_HSUB] = 2<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w;
|
||||
var_values[VAR_VSUB] = 2<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h;
|
||||
|
||||
/* evaluate width and height */
|
||||
av_expr_parse_and_eval(&res, (expr = scale->w_expr),
|
||||
var_names, var_values,
|
||||
NULL, NULL, NULL, NULL, NULL, 0, ctx);
|
||||
scale->w = var_values[VAR_OW] = res;
|
||||
if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr),
|
||||
var_names, var_values,
|
||||
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
|
||||
goto fail;
|
||||
scale->h = var_values[VAR_OH] = res;
|
||||
/* evaluate again the width, as it may depend on the output height */
|
||||
if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr),
|
||||
var_names, var_values,
|
||||
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0)
|
||||
goto fail;
|
||||
scale->w = res;
|
||||
|
||||
w = scale->w;
|
||||
h = scale->h;
|
||||
|
||||
/* sanity check params */
|
||||
if (w < -1 || h < -1) {
|
||||
av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n");
|
||||
return AVERROR(EINVAL);
|
||||
}
|
||||
if (w == -1 && h == -1)
|
||||
scale->w = scale->h = 0;
|
||||
|
||||
if (!(w = scale->w))
|
||||
w = inlink->w;
|
||||
@ -159,6 +229,11 @@ static int config_props(AVFilterLink *outlink)
|
||||
return AVERROR(EINVAL);
|
||||
|
||||
return 0;
|
||||
|
||||
fail:
|
||||
av_log(NULL, AV_LOG_ERROR,
|
||||
"Error when evaluating the expression '%s'\n", expr);
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user