[FFmpeg-cvslog] doc/filters: add geq gradient examples

Lou Logan git at videolan.org
Wed Sep 17 00:07:14 CEST 2014


ffmpeg | branch: master | Lou Logan <lou at lrcd.com> | Mon Sep 15 18:07:09 2014 -0800| [9c9aec33c0cf5789962e2dfa0a1db619d522c61c] | committer: Lou Logan

doc/filters: add geq gradient examples

Radial gradient by Víctor Paesa. Linear gradient by Paul Gentemann.

Also-by: Víctor Paesa <victorpaesa at googlemail.com>
Also-by: Paul Gentemann <beriukay at gmail.com>
Signed-off-by: Lou Logan <lou at lrcd.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9c9aec33c0cf5789962e2dfa0a1db619d522c61c
---

 doc/filters.texi |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/doc/filters.texi b/doc/filters.texi
index e9dab47..02bb34e 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -5144,6 +5144,22 @@ Modify RGB components depending on pixel position:
 @example
 geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'
 @end example
+
+ at item
+Create a radial gradient that is the same size as the input (also see
+the @ref{vignette} filter):
+ at example
+geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray
+ at end example
+
+ at item
+Create a linear gradient to use as a mask for another filter, then
+compose with @ref{overlay}. In this example the video will gradually
+become more blurry from the top to the bottom of the y-axis as defined
+by the linear gradient:
+ at example
+ffmpeg -i input.mp4 -filter_complex "geq=lum=255*(Y/H),format=gray[grad];[0:v]boxblur=4[blur];[blur][grad]alphamerge[alpha];[0:v][alpha]overlay" output.mp4
+ at end example
 @end itemize
 
 @section gradfun



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