We've observed an issue when ADV7612 is fed audio/video from a certain HDMI 2.0 Source device, when the Source is outputting 1080p60 at 8bpc RGB, with 48kHz 2 channel LPCM audio. We can't reproduce this same issue with an ADV7619-based Sink device.
The ADV7619-based unit is one we have developed, and the ADV7612-based one is from another manufacturer we're working with to resolve this issue. The HDMI 2.0 Source is also a device we have developed.
- According to the developers involved on the ADV7612 device, when video + audio are sent from this device, they see DE_REGEN_LCK_RAW getting unset. However, on the ADV7619-based unit, we don't see this. (The ADV7619 is rock solid and stable, and audio/video are constant and functioning normally.)
- DE_REGEN_LCK_RAW (and the corresponding video) is stable until audio is enabled on the Source.
- DE_REGEN_LCK_RAW continues to toggle even after audio is disabled.
- If we change the Hsync pulse's front porch by 4 pixels in either direction, the ADV7612 begins to work.
- We only see this with a single Source device -- other Sources with the Hsync in the nominal location don't have this issue.
- We've tried this with two different ADV7612-based devices and two different Source units.
Is there something we should look at on the ADV7612/ADV7619 settings that we should be comparing between them that would potentially cause this? The fact that video DE becomes unstable is puzzling to us. Thanks for any help you can provide!