Add remoting plugin for output streaming

Remoting plugin support streaming image of virtual output on drm-backend
to remote output. By appending remote-output section in weston.ini,
weston loads remoting plugin module and creates virtual outputs via
remoting plugin. The mode, host, and port properties are configurable in
remote-output section.

This plugin send motion jpeg images to client via RTP using gstreamer.
Client can receive by using following pipeline of gst-launch.

gst-launch-1.0 rtpbin name=rtpbin \
   udpsrc caps="application/x-rtp,media=(string)video,clock-rate=(int)90000,
		encoding-name=JPEG,payload=26" port=[PORTNUMBER] !
          rtpbin.recv_rtp_sink_0 \
   rtpbin. ! rtpjpegdepay ! jpegdec ! autovideosink \
   udpsrc port=[PORTNUMBER+1] ! rtpbin.recv_rtcp_sink_0 \
   rtpbin.send_rtcp_src_0 !
          udpsink port=[PORTNUMBER+2] sync=false async=false

where, PORTNUMBER is specified in weston.ini.

Signed-off-by: Tomohito Esaki <etom@igel.co.jp>

man/weston-drm.man

@@ -45,6 +45,13 @@ including
 can run on other VTs. On switching back to Weston's VT, input devices
 and DRM master are re-acquired through the parent process
 .BR weston-launch .
+
+The DRM backend also supports virtual outputs that are transmitted over
+an RTP session as a series of JPEG images (RTP payload type 26) to a remote
+client. Virtual outputs are configured in the
+.BR remote-output
+section of
+.BR weston.ini.
 .
 .\" ***************************************************************
 .SH CONFIGURATION
@@ -138,6 +145,30 @@ Defaults to false. Note that
 When a connector is disconnected, there is no EDID information to provide
 a list of video modes. Therefore a forced output should also have a
 detailed mode line specified.
+
+.SS Section remote-output
+.TP
+\fBname\fR=\fIname\fR
+Specify unique name for the output.
+.TP
+\fBmode\fR=\fImode\fR
+Specify the video mode for the output. The argument
+.I mode
+is a resolution setting, such as:
+.TP
+\fBmode\fR=\fIwidthxheight\fR
+.TP
+\fBmode\fR=\fIwidthxheight@refresh_rate
+If refresh_rate is not specified it will default to a 60Hz.
+.TP
+\fBhost\fR=\fIhost\fR
+Specify the host name or IP Address that the remote output will be
+transmitted to.
+.TP
+\fBport\fR=\fIport\fR
+Specify the port number to transmit the remote output to. Usable port range
+is 1-65533.
+
 .
 .\" ***************************************************************
 .SH OPTIONS

man/weston.ini.man

@@ -189,6 +189,19 @@ useful for debugging a crash on start-up when it would be inconvenient to
 launch weston directly from a debugger. Boolean, defaults to
 .BR false .
 There is also a command line option to do the same.
+.TP 7
+.BI "remoting="remoting-plugin.so
+specifies a plugin for remote output to load (string). This can be used to load
+your own implemented remoting plugin or one with Weston as default. Available
+remoting plugins in the
+.IR "__libweston_modules_dir__"
+directroy are:
+.PP
+.RS 10
+.nf
+.BR remoting-plugin.so
+.fi
+.RE
 
 .SH "LIBINPUT SECTION"
 The