[FFmpeg-cvslog] doc: try to improve avoid_negative_ts documentation

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Mon Mar 18 23:08:56 2013 +0100| [aafbfb1c2ea2fe238e8cb50702805e4fdb1a2d78] | committer: Michael Niedermayer

doc: try to improve avoid_negative_ts documentation

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=aafbfb1c2ea2fe238e8cb50702805e4fdb1a2d78
---

 doc/ffmpeg-formats.texi |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/doc/ffmpeg-formats.texi b/doc/ffmpeg-formats.texi
index 30cf415..381e325 100644
--- a/doc/ffmpeg-formats.texi
+++ b/doc/ffmpeg-formats.texi
@@ -142,6 +142,10 @@ Use wallclock as timestamps.
 @item avoid_negative_ts @var{integer} (@emph{output})
 Shift timestamps to make them positive. 1 enables, 0 disables, default
 of -1 enables when required by target format.
+When timestamps are shifted, all timestamps of a output file are shifted
+together by the same amount. AV sync, subtitle sync and relative timestamp
+differences are preserved compared to how they would have been without
+shifting.
 @end table
 
 @c man end FORMAT OPTIONS