I'm seeing 4K output video drops every 8-10 seconds and some horizontal lines randomly show on screen as as well. The issue was initially seen from our development board applied with ADV7626. Then I checked the EVAL-ADV7625-SMZ (release 2.3.3), saw same issue.
The source device is an Android TV box, it is similar as this one: http://www.amazon.com/RedSun-S82B-Quad-Android-Bluetooth/dp/B00LUAYG8G/ref=sr_1_1?ie=UTF8&qid=1441399421&sr=8-1&keywords=mbox+s82&pebp=1441399426738&perid=1TR59JTWYDJH4C5PCCV2
If directly connecting the above source device to monitors (Asus, Dell) or QuantumData 780C, the 4K video is good without any issue.
I tested EVAL-ADV7625-SMZ with latest scripts, saw different results by setting ADV7626 in 1) Mux mode, 2) Splitter mode with enabling/disabling CP-A lite mode:
1) MUX mode (IO 0x03 = 0xA6): ADV7626 works well with 4K video. No issue
2) Splitter mode:
a) Enabling CP-A Lite (IO 0x02 = 0x20 and 0x03 = 0x66):
4K video didn't drop but random horizontal lines showed on screen
b) Disabling CP-A Lite (IO 0x02 = 0x20 and 0x03 = 0x26):
4K video DID drop every couple seconds and random horizontal lines showed on screen as well.
In our project, the ADV7626 must be set in Splitter mode and enable CP-A module as well, so we are facing the 4K video issue. Since we can reproduce the issue on EVAL-ADV7625-SMZ board, we would appreciate any help from ADI.
Please find the attached file which is the latest scripts used in the above testing.