[FFmpeg-cvslog] lavfi/histogram: make waveform mode more useful
Paul B Mahol
git at videolan.org
Sat Feb 9 17:25:47 CET 2013
ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Sat Feb 9 16:05:28 2013 +0000| [4fa9defc7fdec348d84be912745a166fa6635b8b] | committer: Paul B Mahol
lavfi/histogram: make waveform mode more useful
Now it displays all color components (not just luma)
either in parade or overlay and also works with RGB colorspace.
Signed-off-by: Paul B Mahol <onemda at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4fa9defc7fdec348d84be912745a166fa6635b8b
---
doc/filters.texi | 33 ++++++++++++++++++++++++++++---
libavfilter/vf_histogram.c | 46 ++++++++++++++++++++++++++++----------------
2 files changed, 59 insertions(+), 20 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 0a2a374..da80ff5 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3146,9 +3146,9 @@ chroma values in vectorscope, similar as @code{color} but actual chroma values
are displayed.
@item waveform
-per row/column luminance graph. In row mode the left side represents luma = 0
-and right side represents luma = 255. In column mode top side represends
-luma = 0 and bottom side represents luma = 255.
+per row/column color component graph. In row mode graph in the left side represents
+color component value 0 and right side represents value = 255. In column mode top
+side represents color component value = 0 and bottom side represents value = 255.
@end table
Default value is @code{levels}.
@@ -3168,6 +3168,33 @@ Default value is @code{10}. Allowed range is [1, 255].
@item waveform_mode
Set mode for @code{waveform}. Can be either @code{row}, or @code{column}.
Default is @code{row}.
+
+ at item display_mode
+Set display mode for @code{waveform}.
+It accepts the following values:
+ at table @samp
+ at item parade
+Display separate waveforms for the color components side by side in
+ at code{row} mode or one below other in @code{column} mode.
+
+In this display mode it is easy to spot color casts in the highlights and
+shadows of an image, by comparing the contours of the top and the bottom
+of each waveform. Since whites, grays, and blacks are characterized by
+exactly equal amounts of red, green, and blue, neutral areas of the
+picture should display three waveforms of roughly equal height.
+If not, the correction is easy to make by making adjustments to level the
+three waveforms.
+
+ at item overlay
+Presents information that's identical to that in the @code{parade}, except
+that the waveforms representing color components are superimposed directly
+over one another.
+
+This display mode can make it easier to spot the relative differences or
+similarities in overlapping areas of the color components that are supposed
+to be identical, such as neutral whites, grays, or blacks.
+ at end table
+Default is @code{parade}.
@end table
@subsection Examples
diff --git a/libavfilter/vf_histogram.c b/libavfilter/vf_histogram.c
index 22de387..ee9689f 100644
--- a/libavfilter/vf_histogram.c
+++ b/libavfilter/vf_histogram.c
@@ -47,6 +47,7 @@ typedef struct HistogramContext {
int scale_height;
int step;
int waveform_mode;
+ int display_mode;
} HistogramContext;
#define OFFSET(x) offsetof(HistogramContext, x)
@@ -64,6 +65,9 @@ static const AVOption histogram_options[] = {
{ "waveform_mode", "set waveform mode", OFFSET(waveform_mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "waveform_mode"},
{ "row", NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "waveform_mode" },
{ "column", NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "waveform_mode" },
+ { "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" },
{ NULL },
};
@@ -99,10 +103,10 @@ static int query_formats(AVFilterContext *ctx)
const enum AVPixelFormat *pix_fmts;
switch (h->mode) {
+ case MODE_WAVEFORM:
case MODE_LEVELS:
pix_fmts = levels_pix_fmts;
break;
- case MODE_WAVEFORM:
case MODE_COLOR:
case MODE_COLOR2:
pix_fmts = color_pix_fmts;
@@ -153,9 +157,9 @@ static int config_output(AVFilterLink *outlink)
break;
case MODE_WAVEFORM:
if (h->waveform_mode)
- outlink->h = 256;
+ outlink->h = 256 * FFMAX(h->ncomp * h->display_mode, 1);
else
- outlink->w = 256;
+ outlink->w = 256 * FFMAX(h->ncomp * h->display_mode, 1);
break;
case MODE_COLOR:
case MODE_COLOR2:
@@ -223,23 +227,31 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)
break;
case MODE_WAVEFORM:
if (h->waveform_mode) {
- for (i = 0; i < inlink->w; i++) {
- for (j = 0; j < inlink->h; j++) {
- int pos = in->data[0][j * in->linesize[0] + i] * out->linesize[0] + i;
- unsigned value = out->data[0][pos];
- value = FFMIN(value + h->step, 255);
- out->data[0][pos] = value;
+ for (k = 0; k < h->ncomp; k++) {
+ int offset = k * 256 * h->display_mode;
+ for (i = 0; i < inlink->w; i++) {
+ for (j = 0; j < inlink->h; j++) {
+ int pos = (offset +
+ in->data[k][j * in->linesize[k] + i]) *
+ out->linesize[k] + i;
+ unsigned value = out->data[k][pos];
+ value = FFMIN(value + h->step, 255);
+ out->data[k][pos] = value;
+ }
}
}
} else {
- for (i = 0; i < inlink->h; i++) {
- src = in ->data[0] + i * in ->linesize[0];
- dst = out->data[0] + i * out->linesize[0];
- for (j = 0; j < inlink->w; j++) {
- int pos = src[j];
- unsigned value = dst[pos];
- value = FFMIN(value + h->step, 255);
- dst[pos] = value;
+ for (k = 0; k < h->ncomp; k++) {
+ int offset = k * 256 * h->display_mode;
+ for (i = 0; i < inlink->h; i++) {
+ src = in ->data[k] + i * in ->linesize[k];
+ dst = out->data[k] + i * out->linesize[k];
+ for (j = 0; j < inlink->w; j++) {
+ int pos = src[j] + offset;
+ unsigned value = dst[pos];
+ value = FFMIN(value + h->step, 255);
+ dst[pos] = value;
+ }
}
}
}
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