@malik_cisse
Can you confirm please?
According to RM below I thought this would not be possible.
sensor input is bayer rgb ,and ISP output is YUV422I, on the fly to DISPLAY(wayland sink with some options).
Too month ago, I did test dual 4K ISP on console using gstreamer.
I opened 2 consoles by ssh and I executed gst-launch for each.
I modified dual basler in "run.sh" and "start_isp.sh".
and I modified i2c channel ( actually. this memory is not exact )
finally, I just confirm 15fps message. I didn't check frame count.
( It is possible that frame rate is lower than 15fps. )
==== and, my turn^^ ====

In above diagram,
If we use 4K on ISI_0, chain_buf borrow ISI_1's line buffer.

So, ISI_1 could not use Line Buffer.
Also, I tested several method, but Streams Image changed to all greens.
Could you explain more how to open case2's streams, please?
================== finally ===================
where is nxp staff?
Please, Confirm or Answer This Issues.