From b35e5d985dd12acf9a0aaa52334134edcf35d68e Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Wed, 12 Dec 2012 13:19:16 -0500
Subject: [PATCH] doc: improve documentation for the asyncts filter first_pts
 option

Note the time base for the option. Add an additional example description.
---
 doc/filters.texi | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index 55e4468fd6..34db2f4630 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -250,11 +250,12 @@ Maximum compensation in samples per second. Relevant only with compensate=1.
 Default value 500.
 
 @item first_pts
-Assume the first pts should be this value.
+Assume the first pts should be this value. The time base is 1 / sample rate.
 This allows for padding/trimming at the start of stream. By default, no
 assumption is made about the first frame's expected pts, so no padding or
 trimming is done. For example, this could be set to 0 to pad the beginning with
-silence if an audio stream starts after the video stream.
+silence if an audio stream starts after the video stream or to trim any samples
+with a negative pts due to encoder delay.
 
 @end table