I'm trying to get to the bottom of an issue with our system regarding output from an ADV7188 device. We're feeding it a multiplexed PAL source and can record video from it successfully, but the first 20/21 lines of video have a curious corruption to them
Essentially every other line presents as green only, with luminance values seemingly intact, for the first 20 or so lines.
The video is being de-interlaced by a PLD and then compressed via an ADV212. However, we have seen the same issue with the ADV7188 connected directly to the ADV212.
We can successfully record from other PAL sources without seeing this issue, so I believe it is something to do with the specific PAL source we are using. However, feeding this PAL source into a standard monitor does not exhibit this behaviour - these lines are all present and 'uncorrupted'.
I've tried various register settings to see if I can remove this, but to no avail. I wondered if any experts on the forums could point me in the right direction as to which configuration areas might cause something like this. I was initially thinking that maybe VDP/VBI processing might be the issue, but I've turned those functions off entirely (and various other combinations of function) without any effect.
I know there is a private register sub map with various settings, so I thought I'd ask here in case something in that register map might be able to cure this issue.
Many thanks in advance for any help you can offer.