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lavfi/histogram: logarithmic mode for levels 

Signed-off-by: Paul B Mahol <onemda@gmail.com>
This commit is contained in:
Paul B Mahol 2013-05-15 12:36:41 +00:00
parent fa23f94eac
commit c45b823bf8
2 changed files with 14 additions and 1 deletions
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4
doc/filters.texi
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@ -4294,6 +4294,10 @@ components that are supposed to be identical, such as neutral whites, grays,
or blacks.
@end table
Default is @code{parade}.
@item levels_mode
Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}.
Default is @code{linear}.
@end table
@subsection Examples

11
libavfilter/vf_histogram.c
View File

@ -48,6 +48,7 @@ typedef struct HistogramContext {
int step;
int waveform_mode;
int display_mode;
int levels_mode;
} HistogramContext;
#define OFFSET(x) offsetof(HistogramContext, x)
@ -68,6 +69,9 @@ static const AVOption histogram_options[] = {
{ "display_mode", "set display mode", OFFSET(display_mode), AV_OPT_TYPE_INT, {.i64=1}, 0, 1, FLAGS, "display_mode"},
{ "parade", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "display_mode" },
{ "overlay", NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "display_mode" },
{ "levels_mode", "set levels mode", OFFSET(levels_mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "levels_mode"},
{ "linear", NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "levels_mode" },
{ "logarithmic", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "levels_mode" },
{ NULL },
};
@ -198,7 +202,12 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
h->max_hval = FFMAX(h->max_hval, h->histogram[i]);
for (i = 0; i < outlink->w; i++) {
int col_height = h->level_height - (h->histogram[i] * (int64_t)h->level_height + h->max_hval - 1) / h->max_hval;
int col_height;
if (h->levels_mode)
col_height = round(h->level_height * (1. - (log2(h->histogram[i] + 1) / log2(h->max_hval + 1))));
else
col_height = h->level_height - (h->histogram[i] * (int64_t)h->level_height + h->max_hval - 1) / h->max_hval;
for (j = h->level_height - 1; j >= col_height; j--) {
if (h->display_mode) {