[FFmpeg-cvslog] doc/filters: correct name for guided filter

[Gyan Doshi]

ffmpeg | branch: master | Gyan Doshi <ffmpeg at gyani.pro> | Thu May 13 19:23:12 2021 +0530| [c122a6c10dedc05933a8b11a3b82f18afc8ca5b7] | committer: Gyan Doshi

doc/filters: correct name for guided filter

Note input requirements and reword option sub description.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c122a6c10dedc05933a8b11a3b82f18afc8ca5b7
---

 doc/filters.texi | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index b574334bea..a218289ddd 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -12957,8 +12957,10 @@ greyedge=difford=1:minknorm=0:sigma=2
 
 @end itemize
 
- at section guided filter
+ at section guided
 Apply guided filter for edge-preserving smoothing, dehazing and so on.
+This filter requires two inputs of same resolution and pixel format.
+The second input serves as the reference.
 
 The filter accepts the following options:
 @table @option
@@ -12975,10 +12977,9 @@ Set filter mode. Can be @code{basic} or @code{fast}.
 Default is @code{basic}.
 
 @item sub
-Set subsampling ratio.
-Allowed range is 1 to 64.
-Default is always 1 for @code{basic} value of @var{mode} option,
-and 4 for @code{fast} value of @var{mode} option.
+Set subsampling ratio for @code{fast} mode.
+Allowed effective range is 2 to 64. Default is 4.
+No subsampling occurs in @code{basic} mode.
 
 @item planes
 Set planes to filter. Default is first only.