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vf_aspect: support variables in evaluating the aspect ratios

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Example: -vf setsar=sar="sar*9/10"

Signed-off-by: Rudolf Polzer <divverent@xonotic.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>
pull/45/head
Rudolf Polzer 11 years ago committed by Anton Khirnov
parent 5928b29f53
commit 34a0ac41a8
3 changed files with 137 additions and 4 deletions
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  1. 1
      Changelog
  2. 54
      doc/filters.texi
  3. 86
      libavfilter/vf_aspect.c

1
Changelog
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@ -45,6 +45,7 @@ version 10:
- raw HEVC, HEVC in MOV/MP4, HEVC in Matroska, HEVC in MPEG-TS demuxing
- remove avplay -vismv option, which has not worked for a long time
- Live HDS muxer
- setsar/setdar filters now support variables in ratio expressions
version 9:

54
doc/filters.texi
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@ -2049,10 +2049,35 @@ This filter accepts the following options:
@table @option
@item dar
Output display aspect ratio, as a rational or a decimal number.
Output display aspect ratio.
@end table
The parameter @var{dar} is an expression 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 w, h
the input width and height
@item a
same as @var{w} / @var{h}
@item sar
input sample aspect ratio
@item dar
input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
@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
For example to change the display aspect ratio to 16:9, specify:
@example
setdar=dar=16/9
@ -2158,10 +2183,35 @@ This filter accepts the following options:
@table @option
@item sar
Output sample aspect ratio, as a rational or decimal number.
Output sample aspect ratio.
@end table
The parameter @var{sar} is an expression 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 w, h
the input width and height
@item a
same as @var{w} / @var{h}
@item sar
input sample aspect ratio
@item dar
input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
@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
For example to change the sample aspect ratio to 10:11, specify:
@example
setsar=sar=10/11

86
libavfilter/vf_aspect.c
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@ -26,13 +26,42 @@
#include <float.h>
#include "libavutil/common.h"
#include "libavutil/eval.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "internal.h"
#include "video.h"
static const char *const var_names[] = {
"PI",
"PHI",
"E",
"w",
"h",
"a", "dar",
"sar",
"hsub",
"vsub",
NULL
};
enum var_name {
VAR_PI,
VAR_PHI,
VAR_E,
VAR_W,
VAR_H,
VAR_A, VAR_DAR,
VAR_SAR,
VAR_HSUB,
VAR_VSUB,
VARS_NB
};
typedef struct {
const AVClass *class;
AVRational dar;
@ -40,6 +69,7 @@ typedef struct {
#if FF_API_OLD_FILTER_OPTS
float aspect_num, aspect_den;
#endif
char *ratio_expr;
} AspectContext;
#if FF_API_OLD_FILTER_OPTS
@ -68,12 +98,54 @@ static int filter_frame(AVFilterLink *link, AVFrame *frame)
#define OFFSET(x) offsetof(AspectContext, x)
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM
static int get_aspect_ratio(AVFilterLink *inlink, AVRational *aspect_ratio)
{
AVFilterContext *ctx = inlink->dst;
AspectContext *s = inlink->dst->priv;
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
double var_values[VARS_NB], res;
int ret;
var_values[VAR_PI] = M_PI;
var_values[VAR_PHI] = M_PHI;
var_values[VAR_E] = M_E;
var_values[VAR_W] = inlink->w;
var_values[VAR_H] = inlink->h;
var_values[VAR_A] = (double) inlink->w / inlink->h;
var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ?
(double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
var_values[VAR_DAR] = var_values[VAR_A] * var_values[VAR_SAR];
var_values[VAR_HSUB] = 1 << desc->log2_chroma_w;
var_values[VAR_VSUB] = 1 << desc->log2_chroma_h;
/* evaluate new aspect ratio*/
if ((ret = av_expr_parse_and_eval(&res, s->ratio_expr,
var_names, var_values,
NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
av_log(NULL, AV_LOG_ERROR,
"Error when evaluating the expression '%s'\n", s->ratio_expr);
return ret;
}
*aspect_ratio = av_d2q(res, INT_MAX);
return 0;
}
#if CONFIG_SETDAR_FILTER
/* for setdar filter, convert from frame aspect ratio to pixel aspect ratio */
static int setdar_config_props(AVFilterLink *inlink)
{
AspectContext *s = inlink->dst->priv;
AVRational dar;
int ret;
#if FF_API_OLD_FILTER_OPTS
if (!(s->aspect_num > 0 && s->aspect_den > 0)) {
#endif
if ((ret = get_aspect_ratio(inlink, &s->dar)))
return ret;
#if FF_API_OLD_FILTER_OPTS
}
#endif
if (s->dar.num && s->dar.den) {
av_reduce(&s->sar.num, &s->sar.den,
@ -98,7 +170,7 @@ static const AVOption setdar_options[] = {
{ "dar_num", NULL, OFFSET(aspect_num), AV_OPT_TYPE_FLOAT, { .dbl = 0 }, 0, FLT_MAX, FLAGS },
{ "dar_den", NULL, OFFSET(aspect_den), AV_OPT_TYPE_FLOAT, { .dbl = 0 }, 0, FLT_MAX, FLAGS },
#endif
{ "dar", "display aspect ratio", OFFSET(dar), AV_OPT_TYPE_RATIONAL, { .dbl = 0 }, 0, INT_MAX, FLAGS },
{ "dar", "display aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "1" }, .flags = FLAGS },
{ NULL },
};
@ -150,6 +222,16 @@ AVFilter ff_vf_setdar = {
static int setsar_config_props(AVFilterLink *inlink)
{
AspectContext *s = inlink->dst->priv;
int ret;
#if FF_API_OLD_FILTER_OPTS
if (!(s->aspect_num > 0 && s->aspect_den > 0)) {
#endif
if ((ret = get_aspect_ratio(inlink, &s->sar)))
return ret;
#if FF_API_OLD_FILTER_OPTS
}
#endif
inlink->sample_aspect_ratio = s->sar;
@ -161,7 +243,7 @@ static const AVOption setsar_options[] = {
{ "sar_num", NULL, OFFSET(aspect_num), AV_OPT_TYPE_FLOAT, { .dbl = 0 }, 0, FLT_MAX, FLAGS },
{ "sar_den", NULL, OFFSET(aspect_den), AV_OPT_TYPE_FLOAT, { .dbl = 0 }, 0, FLT_MAX, FLAGS },
#endif
{ "sar", "sample (pixel) aspect ratio", OFFSET(sar), AV_OPT_TYPE_RATIONAL, { .dbl = 1 }, 0, INT_MAX, FLAGS },
{ "sar", "sample (pixel) aspect ratio", OFFSET(ratio_expr), AV_OPT_TYPE_STRING, { .str = "1" }, .flags = FLAGS },
{ NULL },
};

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