Document unsynchronized HDMI/SDI output.

[nageru-docs] / hdmisdi.rst

diff --git a/hdmisdi.rst b/hdmisdi.rst
index f6f032cf48a29df3c27cb9e6a4b8359a2242d6d2..a04c62ba3d09336680d80acb5d6936a2f75e90a8 100644 (file)
--- a/hdmisdi.rst
+++ b/hdmisdi.rst
@@ -8,14 +8,14 @@ the stream on another PC, but for many uses, the end-to-end latency is
 too high, and you might not want to involve a full extra PC just for this
 anyway.
 
 too high, and you might not want to involve a full extra PC just for this
 anyway.
 

-Thus, since 1.5.0, Nageru supports using a spare output card for HDMI/SDI
+Thus, Nageru supports using a spare output card for HDMI/SDI

 output, turning it into a simple, reasonably low-latency audio/video switcher.
 
 
 Setting up HDMI/SDI output
 --------------------------
 
 output, turning it into a simple, reasonably low-latency audio/video switcher.
 
 
 Setting up HDMI/SDI output
 --------------------------
 

-Turning on HDMI/SDI output is simple; just right-click on the live view and
+To turn on HDMI/SDI output, right-click on the live view and

 select the output card. (Equivalently, you can access the same functionality
 from the *Video* menu in the regular menu bar, or you can give the
 *--output-card=* parameter on the command line.) Currently, this is supported
 select the output card. (Equivalently, you can access the same functionality
 from the *Video* menu in the regular menu bar, or you can give the
 *--output-card=* parameter on the command line.) Currently, this is supported


@@ -26,11 +26,23 @@ keep running just as before.
 A video mode will automatically be picked for you, favoring 59.94 fps if possible,
 but you can change the mode on-the-fly to something else if you'd like,
 as long as the resolution matches with what you've set up at program start.
 A video mode will automatically be picked for you, favoring 59.94 fps if possible,
 but you can change the mode on-the-fly to something else if you'd like,
 as long as the resolution matches with what you've set up at program start.

-Note that whenever HDMI/SDI output is active, the output card will be the
+
+
+Unsynchronized HDMI/SDI output
+------------------------------
+
+By default, whenever HDMI/SDI output is active, the output card will be the

 master clock; you cannot change it to any of the input cards. This also means
 that the frame rate you choose here will determine the frame rate for the
 stream.
 
 master clock; you cannot change it to any of the input cards. This also means
 that the frame rate you choose here will determine the frame rate for the
 stream.
 

+In Nageru 2.1.0 or newer, you can use the flag --output-card-unsynchronized
+to counteract this (there is currently no way to do it from the GUI).
+This is for if you want just a monitor output without synchronizing
+your entire stream chain to the output card (ie., you want to keep
+some other camera as the master). Sound support is untested, and is
+probably going to crackle a fair bit.
+

 
 A note on latency
 -----------------
 
 A note on latency
 -----------------


@@ -171,7 +183,7 @@ Measuring latency
 
 In order to optimize latency, it can be useful to measure it, but for most
 people, it's hard to measure delays precisely enough to distinguish reliably
 
 In order to optimize latency, it can be useful to measure it, but for most
 people, it's hard to measure delays precisely enough to distinguish reliably

-between e.g. 70 and 80 milliseconds by eye alone. Nageru gives you some simple
+between e.g. 70 and 80 milliseconds by eye alone. Nageru gives you some

 tools that will help.
 
 The most direct is the flag *--print-video-latency*. This samples, for every
 tools that will help.
 
 The most direct is the flag *--print-video-latency*. This samples, for every