Composite video output problem

Mirarty

Hello all,
I need help with composite video output.
First it was not working at all. I disabled hdmi_force_hotplug=1 in config.txt; now the boot section working, but then image is black. I tested different linux distros and Lineage OS and it was working so I believe hardware is good.
Here is short video what I mean by "boot section":
https://youtu.be/nV03GtdeKUI

I believe it is only some setting I need to change. Anyone who can help?

Cee123

I can help. I had a similar issue displaying output on my Sony Bravia TV where it would say "unsupported signal". I finally got it to display by editing the config file. I made a video about it here.
https://youtu.be/OF-dfJEvYrY

I was frustrated because I paid $69 for this but couldn't get it to display on any output. Took me ages trying different settings. So if I can save other people the trouble..

Cee123

Some simple edits to the config.txt file should get the display working.

What I did was change:
dtoverlay=vc4-kms-v3d,cma-256
to
dtoverlay=vc4-fkms-v3d,cma-256

The rest is optional.
Step 2: hdmi_group=1
Step 3: hdmi_mode=16
Step 4: hdmi_cvt=1920 1080 60 6 0 0 0

Good luck, I hope this works.

Mirarty

Thank you for your suggestion, but HDMI is working fine form me. I just need composite video.
I tried to add sdtv_mode=0 and sdtv_aspect=3 but this doesn't work. Looks like config.txt has control over boot section only and there is another file which need to be configured for system.
Any suggestion?

Cee123

Ohhh ok. I don't know much about composite video output. Hope someone else can help.

Mirarty

It is possible somewhere in settings change frequency to 30Hz instead of 60Hz? I'm curious if this can fix my problem.

Cee123

I think this line
hdmi_cvt=1920 1080 60 6 0 0 0
---------^ resolution ^refresh rate

Not sure what the command would be for composite video 🙁