Reply To: No image behind HDMI switch / audio extractor in HDMI TX mode

[marqs]

I got the same DigiSun AH231U HDMI switch for testing, and found out that its issue is similar to some Denon AVRs as the switch relies a bit too much on HDMI metadata. When VIC is set to 0 (unknown), the switch ends up using inoptimal RX/TX configuration for most modes which leads to missing/corrupted/jittery output. With the firmware modified for Denons, test pattern and standard passthru modes work OK since they explicitly set VIC. However, other modes using VIC=0 had still issues but after forcing the default VIC to 2 (480p60), the output seemed to be fine in all modes I quickly tried. One thing I noticed though, is that the switch occasionally had issues locking after a mode switch unless “Full TX setup” was enabled in OSSC Compatibility opts.

To summarize, HDMI signal handling of this switch is not very robust. It can be made to work reliably with OSSC if another compatibility option is added that sets default VIC to a known value.