I use an old Raspberry Pi B as PAL video pattern generator. It works very well. My previous media player (MED500X2) also had a PAL video output, next to its HDMI output. Does the RP module in my Slice generate PAL video? I have a vintage (1951) analog TV next to my fat widescreen that I’d like to have video on simultaneously. The 3.5mm socket seems to carry only audio but the Broadcom chip does analog video without breaking a sweat. I’m not afraid to void my warranty and my soldering skills are up to spec.
The VEC output would be enabled if you remove the hdmi_force=1 from config.txt and don’t plug in an HDMI display.
But it would require you soldering a connection to the 120 odd pin SODIMM connector so your soldering skills had better be bordering on the level of expert to professional.
Thing is, I want HDMI and analog video simultaneously. If I can have PAL but no digital video out then the whole exercise is moot. Incidentally, the SODIMM has 200 pins. Pin #166 is TVDAC. I haven’t tried my RPI with both analog and HDMI connected, maybe should try that first. The compute module shouldn’t differ too much from it. The hdmi_force directive seems eerily familiar.
No it is not possible to output HDMI and composite at the same time on the BCM2835 Architecture.