doc/filters: document expr support in fps filter

Added in dd770883e9
3 years ago · 604924a069
parent fcb80aa289
commit 604924a069
1 changed files with 21 additions and 1 deletions
--- a/doc/filters.texi
+++ b/doc/filters.texi
@ -12334,7 +12334,27 @@ It accepts the following parameters:
@table @option

@item fps
-The desired output frame rate. The default is @code{25}.
+The desired output frame rate. It accepts expressions containing the following
+constants:
+
+@table @samp
+@item source_fps
+The input's frame rate
+
+@item ntsc, qntsc, sntsc
+NTSC frame rate of @code{30000/1001}
+
+@item pal, qpal, spal
+PAL frame rate of @code{25.0}
+
+@item film
+Film frame rate of @code{24.0}
+
+@item ntsc_film
+NTSC-film frame rate of @code{24000/1001}
+@end table
+
+The default is @code{25}.

@item start_time
 Assume the first PTS should be the given value, in seconds. This allows for