PI OS does not provide a mechanism to disable the modulated chrominance signal in the composite video output. This reduces the resolution and video quality when connecting to older monochrome CRTs. This forum post describes the problem more elegantly than I can.
viewtopic.php?t=248217
Basically the only mechanism provided by PI OS (sdtv_disable_colourburst=1) does not disable the chroma signal. I've searched for solutions in the past and just found people complaining about the same thing with no solution. I eventually bumped into the python application called tweakvec. It does provide a mechanism to disable the color chroma signal (CHRDIS). But, it's a bulky python app, not something I want to run at startup using systemd.
So, I developed a simple C application to properly switch the composite output to a true monochrome composite signal. The app is called pivec. You can find it here on githib.
https://github.com/racerxr650r/pivec
The readme provides before/after comparison, build and installation instructions, and usage info.
viewtopic.php?t=248217
Basically the only mechanism provided by PI OS (sdtv_disable_colourburst=1) does not disable the chroma signal. I've searched for solutions in the past and just found people complaining about the same thing with no solution. I eventually bumped into the python application called tweakvec. It does provide a mechanism to disable the color chroma signal (CHRDIS). But, it's a bulky python app, not something I want to run at startup using systemd.
So, I developed a simple C application to properly switch the composite output to a true monochrome composite signal. The app is called pivec. You can find it here on githib.
https://github.com/racerxr650r/pivec
The readme provides before/after comparison, build and installation instructions, and usage info.
Statistics: Posted by d1g1t4l_g33k — Sat Dec 14, 2024 8:51 pm