Scaler II vs Scaler problems

Hi,

I have a similar problem with Scaler II. Maybe you can help me also.

My system contains the next chain:

CVI -> clip -> scaler -> triple frame buffer -> scaler -> clip

It ends with a custom-made conversion modul from Avalon ST to our internal video format. The whole system is built up in block diagram editor with self-made verilog controller modules.

The double clipper/scaler combination is necessary in this system because the output resolution is changed during runtime and a proper synchronization must be set up to other external sources. Without this bandwidth problems would appear.

This systems works well at both 1920x1080p60 and 1920x1200p60 input resolution.

I changed the second scaler to the scaler II. The controller modul was changed to the new type of Avalon MM interface and new register set.

With this setup I got black screen instead of the video. I have made experiences with modifying the scaler parameters and the controller modules but nothing happend. I have no idea what's going on.

I have another problem probably with the scaler I also. The described system above with the scaler I cut several pixels at the right and bottom side of the video when it is scaled down. The number of cut down pixels is higher when the output video is smaller. I am talking only about several pixels - we noticed it only after monthes of usage because the effect is so small but it is there.

The strange thing is the output video has exactly the specified resolution which is set by the application SW. There should be somewhere a scaling problem. This is a mystery for me.

Does anybody have similar experience?

Best regards,

Istvan