lavfi/subtitles: introduce stream_index

Signed-off-by: ValdikSS <iam@valdikss.org.ru>

1 files changed, 13 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index a8b2668889..d53f645a55 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -7725,6 +7725,9 @@ changed.
 @item charenc
 Set subtitles input character encoding. @code{subtitles} filter only. Only
 useful if not UTF-8.
+
+@item stream_index, si
+Set subtitles stream index. @code{subtitles} filter only.
 @end table
 
 If the first key is not specified, it is assumed that the first value
@@ -7741,6 +7744,16 @@ which is equivalent to:
 subtitles=filename=sub.srt
 @end example
 
+To render the default subtitles stream from file @file{video.mkv}, use:
+@example
+subtitles=video.mkv
+@end example
+
+To render the second subtitles stream from that file, use:
+@example
+subtitles=video.mkv:si=1
+@end example
+
 @section super2xsai
 
 Scale the input by 2x and smooth using the Super2xSaI (Scale and