nut: Support experimental NUT 4 features

Add the low overhead pipe mode and the extended broadcast mode.
Export the options as 'syncponts' since it impacts only that.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/doc/nut.texi b/doc/nut.texi
index 39a22ff3ea..042c88a3ab 100644
--- a/doc/nut.texi
+++ b/doc/nut.texi
@@ -17,6 +17,27 @@ subtitle and user-defined streams in a simple, yet efficient, way.
 It was created by a group of FFmpeg and MPlayer developers in 2003
 and was finalized in 2008.
 
+@chapter Modes
+NUT has some variants signaled by using the flags field in its main header.
+
+@multitable @columnfractions .4 .4
+@item BROADCAST   @tab Extend the syncpoint to report the sender wallclock
+@item PIPE        @tab Omit completely the syncpoint
+@end multitable
+
+@section BROADCAST
+
+The BROADCAST variant provides a secondary time reference to facilitate
+detecting endpoint latency and network delays.
+It assumes all the endpoint clocks are syncronized.
+To be used in real-time scenarios.
+
+@section PIPE
+
+The PIPE variant assumes NUT is used as non-seekable intermediate container,
+by not using syncpoint removes unneeded overhead and reduces the overall
+memory usage.
+
 @chapter Container-specific codec tags
 
 @section Generic raw YUVA formats