Analog Video Output
Software update 201707120 introduces an Analog PAL Video Output mode using the multiway mini jack on the Rpi. And in Update 201707311 audio routing from the USB microphone to the RPi audio output was also made available.
This mode enables you to feed an analog video transmitter with the Rpi camera and Portsdown test patterns. This is really useful when operating portable as you no longer need an additional camera, test card generator or microphone. This is especially true for 23cms ATV and the 5.6GHz FPV transmitter shown elsewhere on the Wiki.
Set up
The Composite video output mode is selected from the "Output" menu on the console menu, or from Menu 2 on the touchscreen - select "vid out".
Note that the video on the analog output is smooth, not jerky like the viewfinder which is limited to a slow refresh rate.
Hardware connections
Rather than reproduce the connection details, here is a link to a good website describing the pin connections on the 4-terminal 3.5mm jack. http://www.instructables.com/id/Raspberry-Pi-2-Quick-n-Easy-RCA/
It should be noted that there is no standard connection for this jack - do not assume that the mini jack to phonos lead you have in the junk box will be correct!