lavfi/overlay: make use of av_opt_set_from_string()

Simplify.

1 files changed, 11 insertions, 10 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index 42f4a7a0f0..e5e24e9ee9 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -3176,12 +3176,19 @@ Overlay one video on top of another.
 It takes two inputs and one output, the first input is the "main"
 video on which the second input is overlayed.
 
-It accepts the parameters: @var{x}:@var{y}[:@var{options}].
+This filter accepts a list of @var{key}=@var{value} pairs as argument,
+separated by ":". If the key of the first options is omitted, the
+arguments are interpreted according to the syntax @var{x}:@var{y}.
+
+A description of the accepted options follows.
 
-@var{x} is the x coordinate of the overlayed video on the main video,
-@var{y} is the y coordinate. @var{x} and @var{y} are expressions containing
-the following parameters:
+@table @option
+@item x, y
+Set the expression for the x and y coordinates of the overlayed video
+on the main video. Default value is 0.
 
+The @var{x} and @var{y} expressions can contain the following
+parameters:
 @table @option
 @item main_w, main_h
 main input width and height
@@ -3196,12 +3203,6 @@ overlay input width and height
 same as @var{overlay_w} and @var{overlay_h}
 @end table
 
-@var{options} is an optional list of @var{key}=@var{value} pairs,
-separated by ":".
-
-The description of the accepted options follows.
-
-@table @option
 @item rgb
 If set to 1, force the filter to accept inputs in the RGB
 color space. Default value is 0.