Dbus interface or cli means that you are now talking of Istanbul as a service. 

Hence, it won't be easy to correct this if we want to be able to make a screencast of screencast. Because having 2 screencast at the same time means 2 services with different name. And thus, you are not talking of a unique service anymore... a service as only name (one access point)  

The other solution is to seperate the tray icon and the screencast objects:

- one "screencast instance" that provide a DBus service like this

(org.gnome.Istanbul)

    <method name="StartRecording">
      <arg type="d" name="frame_rate" direction="in"/>
      <arg type="d" name="scale_factor" direction="in"/>
      <arg type="b" name="record_3d" direction="in"/>
      <arg type="b" name="record_mousepointer" direction="in"/>
      <arg type="s" name="audio_source" direction="in"/> <-- the audio pipe description 
      <arg type="s" name="tmpfile" direction="out"/> <-- the tmp file, needed to identify the recording
    </method>

    <method name="StopRecording">
      <arg type="s" name="tmpfile" direction="in"/>
    </method>

- and the tray icon that communicates with it..

what do you think?

Created attachment 70000 [details] [review]
start record from command line

This is not a D-Bus service, just a new cmdline option.

`istanbul --record FILE` will immediately start a screencast, recording to FILE, and won't add a tray icon.

The screencast can be stopped by SIGTERM, istanbul will then stop recording,
wait for end of stream and quit.

This is the most basic cmdline support you can get but it works fine (actually
I failed to watch produced video because bug 347761 but it is unrelated).

Also my main use case is running it from inside a Xvfb session and it doesn't
work in that case, the output file is never written to.  This may be a
limitation of Xvfb or istximagesrc, I don't know.  Also unrelated.

Frederic,

Should all the preferences that are gotten from gconf, be still gotten from gconf on a command line or should it be overridden by command line parameters.  Also would you like to be able to specify co-ordinates of the area on the screen to record?

Created attachment 70018 [details] [review]
start record from command line

Modified patch to support setting coordinates and options from cmdline,
this gives:

  --record FILENAME (as before)
  --coords X1,Y1,X2,Y2
  --video-framerate DD
  --video-size [full,half,quarter]
  --record-3d (and --no-record-3d)
  --record-mousepointer (and --no-record-mousepointer)
  --record-sound (and --no-record-sound)

Also SIGINT can also be used to interrupt a screencast (SIGTERM is still supported).

Awesome patch, just tested it and it works well.

I may clean up the command line options later.  Thank you Frederic.