[FFmpeg-cvslog] doc/filters.texi: update overlay_vaapi documentation

[softworkz]

ffmpeg | branch: master | softworkz <softworkz at hotmail.com> | Mon Oct 31 06:20:07 2022 +0000| [e137d197b54a3accfae27d7458f1ee80491cfa7e] | committer: Haihao Xiang

doc/filters.texi: update overlay_vaapi documentation

Signed-off-by: softworkz <softworkz at hotmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e137d197b54a3accfae27d7458f1ee80491cfa7e
---

 doc/filters.texi | 51 ++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 40 insertions(+), 11 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index e1554cb18e..b50582eb2a 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -26321,30 +26321,59 @@ It takes two inputs and has one output. The first input is the "main" video on w
 The filter accepts the following options:
 
 @table @option
-
 @item x
-Set the x coordinate of the overlaid video on the main video.
-Default value is @code{0}.
-
 @item y
-Set the y coordinate of the overlaid video on the main video.
-Default value is @code{0}.
+Set expressions for the x and y coordinates of the overlaid video
+on the main video.
 
- at item w
-Set the width of the overlaid video on the main video.
-Default value is the width of input overlay video.
+Default value is "0" for both expressions.
 
+ at item w
 @item h
-Set the height of the overlaid video on the main video.
-Default value is the height of input overlay video.
+Set expressions for the width and height the overlaid video
+on the main video.
+
+Default values are 'overlay_iw' for 'w' and 'overlay_ih*w/overlay_iw' for 'h'.
+
+The expressions can contain the following parameters:
+
+ at table @option
+
+ at item main_w, W
+ at item main_h, H
+The main input width and height.
+
+ at item overlay_iw
+ at item overlay_ih
+The overlay input width and height.
+
+ at item overlay_w, w
+ at item overlay_h, h
+The overlay output width and height.
+
+ at item overlay_x, x
+ at item overlay_y, y
+Position of the overlay layer inside of main
+
+ at end table
 
 @item alpha
 Set transparency of overlaid video. Allowed range is 0.0 to 1.0.
 Higher value means lower transparency.
 Default value is @code{1.0}.
 
+ at item eof_action
+See @ref{framesync}.
+
+ at item shortest
+See @ref{framesync}.
+
+ at item repeatlast
+See @ref{framesync}.
+
 @end table
 
+This filter also supports the @ref{framesync} options.
 @subsection Examples
 
 @itemize