Hi Pierre,
A possible source/reason for the limited bandwidth is very likely related to the memory bandwidth in the H-Box Shading2D.
The detail where the required coefficients are used is asking for a lot of data from a single RAM module on the ironman platform. In case the CoefficientBuffer(linked to VA online help) is used, we need to verify if the requested bandwidth can be delivered. In the documentation of the hardware ressources a bandwidth of up to 4 GB/s per RAM can be found for the CXP ironman.
The camera is delivering:
(8 bit) * 4672 * 3416 * (148 Hz) = 2.36 GB/s.
The single CoefficientBuffer is requested to deliver:
2 * 2.36 GB/s = 2 * (8 bit) * 4672 * 3416 * (148 Hz) = 4.72 GB/s
Since we can "only" get 4 GB/s instead of 4.72 GB/s we have a limitation here:
((4.0 (GB / s)) / (4.74 (GB / s))) * 148 Hz = 124.89 Hz
That is pretty close the the mentioned 122 Hz in your post and seems to me to be a plausible explanation for the limit you reported.
Below you can see the single RAM that is requested to deliver 4.72 GB/s in practice, while the theory of the used links stated a higher bandwidth:
R.Rudde_SYNC-CoeffBUffer.png
So the option above is causing the limitation.
Now we need a solution for this.
Below two RAMs are used to get the coefficient data for the shading correction.
It is using two RAM modules at full memory bandwidth by using the maximum bit-depth of 64 bit * 8 = 512 bit each and a FIFO with ParallelDN to meet the requested target bandwidth:
R.Rudde_SYNC-Double-CoeffBuffer.png
The modifed VA design can be found here: BRudde_HIGH-BandWidth_CXP-Mono8-4672x3416+shading+bpr+gpi8.va
The requested bandwidth per memory module is now:
(8 bit) * 4672 * 3416 * (148 Hz) = 2.36 GB/s
and can be served by the hardware RAM modules in the ironman CXP.
It are two RAM modules required, but there was one module left.
Please give me some feedback if this solved your issue as expected.
Thank you.
---
Below a second, but minor topic is discussed:
Below I removed an unnecessary SYNC.
The SYNC did not affect the design in a negative way.
R.Rudde_SYNC-Kill.png
Modified VA Design without SYNC: BRudde_CXP-Mono8-4672x3416+shading+bpr+gpi8.va