Video composite

Hi everyone !

I am trying to connect a video transmitter to the video composite output (RCA) on my raspberry Pi 3 B.
With the last version of rasbian from Emlid, I had to modify the /boot/config.txt and uncomment the following lines :
overscan_left=16, overscan_right=16, overscan_top=16, overscan_bottom=16
And everything worked.
However, now the file is different and even if I had these lines it changes nothing.

Can anyone help me to solve this?
Thank you !


I am just stupid it just needs to disconnect the hdmi cable from the raspberry and it automatically recognizes the video composite output.