Extcam protocol basics, Far end video source switching, Far end preset switching – TANDBERG 6000MXP User Manual
Page 227: The extcap and the extname, The extswitch

D 13887.08
MAY 2008
227
TANDBERG 3000
MXP
&
6000
MXP
REFERENCE GUIDE FOR SYSTEM INTEGRATORS
A
ssume you have your cameras connected
to an external control system, and that you
want to be able to control these cameras using
the TANDBERG remote or from the remote site
using FECC (Far End Camera Control).
The control system issues the following com-
mand on a telnet session or on a serial port
connection:
extcam on
Now, when you select a video input with no
codec controllable camera connected, the
following commands will be output to the tel-
net/serial port when you attempt to control the
camera with the TANDBERG remote:
*C
start
*C
stop
where
le
for left
ri
for right
up
for up
do
for down
z+
for zoom in
z-
for zoom out
These commands can be parsed by the control
system and passed on to external cameras as
needed.
NoTe!
For all practical purposes, a start will
always be followed by a stop before a new
movement is allowed.
Far End Video Source Switching
Things get slightly more complicated if you
need to control all types of video switching in
the codec. The control system does this easily
for the local end, but what about video switch
requests from the far end in a call? If you are
not running extcam, or just issued an
extcam
on
command, a far end video switch will cause
the codec to change video source.
So, how can we route far end video switch com-
mands to the control system? The control system
does this by passing the
source=<0..9>
option
to the extcam command:
Example:
extcam on source=4
This tells the far end that your control system
has four sources. If a far end video switch
command is received, it will be routed to the
telnet/serial port as follows:
*C vs 1 m
Meaning that the far end wants to switch to
video source 1, with m – motion video.
Note! The source option affects video switch
commands received over FECC only.
xConfiguration MainVideoSource
etc.
commands are not affected by this, so you are
still able to do local switching as you want.
Far End Preset Switching
The far end may also request that a preset
should be displayed or stored. Since activating
a codec preset can trigger a video switch, the
preset commands can also be routed to the tel-
net/serial port. Use the
pres=<0..15>
option
to specify this. This option can be combined
with the source option.
Example:
extcam on pres=6
This tells the far end that you have 6 selecta-
ble presets. If a far end preset command is
received, it will be routed to the telnet/serial
port:
*C pa 1
Meaning that far end wants to activate preset
1 . If the command is ps it wants to store a
preset at the given position.
Note! The pres option affects preset com-
mands received over FECC only.
xCommand PresetActivate, Preset-
Store, PresetClear
etc. commands are
not affected by this.
The extcap and the extname
When you make a call, the codec will send out
a camera/video source capset consisting of
video source names as specified by the vid-
name command and capabilities as detected
by the internal camera driver. If you have start-
ed extcam with the
source=
option, these
capabilities and names will probably not match
with what you have in your control system.
So, when you use the
source=
option,
the names and capabilities specified by the
extname and extcap commands will be used
instead.
Readers of the original documentation
†
may
recall that it stated that
extcap
and
ext-
name
will output the normal codec settings if
extcam
is off, ie.
extname
will function as
vidname
. This is not correct!
However, the list will be limited to the number
of entries given the last time you started
extcam
with the source option. This is not very
obvious. To keep the control system compatible
with different software versions, it is recom-
mended to start extcam first with the number
of sources you need, then specify names and
capabilities.
Example: We have three external video
sources/cameras:
extcam on source=3
We give them custom names:
extname 1 “Front”
extname 2 “Document”
extname 3 “DVD”
And correct capabilities.
“Front”
is a full
featured camera.
“Document”
is a document
camera with only zoom.
“DVD”
is a DVD player.
extcap 1 ptzfms
extcap 2 zms
extcap 3 ms
If you make a call, the far end should only list
three possible video sources, with names
as specified. If you select the second video
source, far end should not allow any movement
other than zoom.
Note! Do not rely on this. The control system may
still receive movement commands, even if you
have no movement specified in the capset. Be
sure to ignore commands that you don’t expect!
The extswitch
The
extswitch
is used to inform the far
end that you have switched video source with
your control system. Extcam must be started
with the
source=
option for this to be
meaningful.
Example: Assume you have two sources con-
nected to your control system:
extcam on source=2
You do a local switch to the 2nd source on
your control system, and we inform the far end
so it can show information about the selected
source and use correct capabilities:
extswitch
2
The
extswitch
is also used to confirm that
a far end video switch command has been
properly executed. Failure to reply to a FECC
video switch with an
extswitch
means that
the far end will probably assume that no video
switch was executed, and continue to use the
same capabilities and name as the previously
selected source.
Example: Assuming same setup as under
extcap/extname and that the far end requests
a video change to the DVD source:
* C vs 3 m
We change video source in our control system
and confirm the change:
extswitch 3
The far end will now know that we are using the
DVD source, and should not send any move-
ment commands. The far end may elect to
display the source name too.
† The original documentation is the TANDBERG 770-
8000MXP Dataport User Guide, which is available separately.
Controlling External Cameras
Extcam Protocol Basics