[FFmpeg-devel] [PATCH] doc/filters: some more details and modified example to, zmq/azmq

[Bodecs Bela]

Dear All,

I added some more information about default value of bind_address option 
and its abbreviated
version (b). I modified the example to have named instanced filter and 
to show
its use.

please review this patch.

thanky you in advance,

best regards,

Bela Bodecs

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>From 5464b56e6d21f1e87166ada31affc7e63cf6f90d Mon Sep 17 00:00:00 2001
From: Bela Bodecs <bodecsb at vivanet.hu>
Date: Tue, 3 Apr 2018 16:18:02 +0200
Subject: [PATCH] doc/filters: some more details and modified example to
 zmq/azmq

Info about default value of bind_address option and its abbreviated
version (b). Example modified to have named instanced filter and to show
its use.


Signed-off-by: Bela Bodecs <bodecsb at vivanet.hu>
---
 doc/filters.texi | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index bf2b94e..6665bfa 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -221,6 +221,7 @@ Here is a BNF description of the filtergraph syntax:
 @var{FILTERGRAPH}      ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
 @end example
 
+ at anchor{filtergraph escaping}
 @section Notes on filtergraph escaping
 
 Filtergraph description composition entails several levels of
@@ -20267,7 +20268,8 @@ filters in the filtergraph.
 
 @code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq}
 must be inserted between two video filters, @code{azmq} between two
-audio filters.
+audio filters. Both of them are capable to send messages to any filter
+type.
 
 To enable these filters you need to install the libzmq library and
 headers and configure FFmpeg with @code{--enable-libzmq}.
@@ -20277,7 +20279,10 @@ For more information about libzmq see:
 
 The @code{zmq} and @code{azmq} filters work as a libzmq server, which
 receives messages sent through a network interface defined by the
- at option{bind_address} option.
+ at option{bind_address} option. (An alternative, abbreviated  name of this
+option is @option{b}.) Default value of this option is
+"tcp://*:5555". You may want to alter this value to your needs,
+but don't forget to escape ':' signs. (See @ref{filtergraph escaping} section.)
 
 The received message must be in the form:
 @example
@@ -20285,7 +20290,10 @@ The received message must be in the form:
 @end example
 
 @var{TARGET} specifies the target of the command, usually the name of
-the filter class or a specific filter instance name.
+the filter class or a specific filter instance name. The default
+filter instance name is something like this "Parsed_<filter_name>_<index>",
+but you can override this by using filter_name@@id syntax.
+(See @ref{Filtergraph syntax} section.)
 
 @var{COMMAND} specifies the name of the command for the target filter.
 
@@ -20307,14 +20315,17 @@ will send a reply to the client, adopting the format:
 Look at @file{tools/zmqsend} for an example of a zmq client which can
 be used to send commands processed by these filters.
 
-Consider the following filtergraph generated by @command{ffplay}
+Consider the following filtergraph generated by @command{ffplay},
+We specify instance name for the 1st overlay filter only,
+the other ones will have default instance names.
+
 @example
 ffplay -dumpgraph 1 -f lavfi "
 color=s=100x100:c=red  [l];
 color=s=100x100:c=blue [r];
 nullsrc=s=200x100, zmq [bg];
-[bg][l]   overlay      [bg+l];
-[bg+l][r] overlay=x=100 "
+[bg][l]   overlay     [bg+l];
+[bg+l][r] overlay@@my=x=100 "
 @end example
 
 To change the color of the left side of the video, the following
@@ -20328,6 +20339,12 @@ To change the right side:
 echo Parsed_color_1 c pink | tools/zmqsend
 @end example
 
+To change the position of the right side:
+ at example
+echo overlay@@my x 150 | tools/zmqsend
+ at end example
+
+
 @c man end MULTIMEDIA FILTERS
 
 @chapter Multimedia Sources
-- 
2.5.3.windows.1