Force 1080i video at 59.94fps

Question

I'm trying to set up a Raspberry pi to output video to an ancient TV transmitter which requires HD interlaced video at 59.94fps.

The Pi HDMI output is connected to a BlackMagic micro HDMI to SDI converter, which reports many supported formats, so auto-detection doesn't work. I believe I need to force the correct video output, probably with something in config.txt.

I can temporarily enable the correct output format with this command:

tvservice -e "CEA 5 HDMI" --ntsc

I can save the CEA 5 HDMI part to /boot/config.txt like this:

hdmi_group=1
hdmi_mode=5

But when I reboot I get 60fps output, not 59.94fps.

How can I force 59.94fps?

Answer 1

There seems to be no way to set this mode in /boot/config.txt.

What worked for me was to follow @JaromandaX's suggestion and put the tvservice -e "CEA 5 HDMI" --ntsc command in /etc/rc.local.