Do "Scaler II (4K ready)" in general have a problem with downscaling more than a factor 4?

[MLaur2]

I have a video application, designed in Qsys v. 16.1.

Had some issues with the "Scaler II (4K ready)". During debug, I have cut away everything else, thus my Qsys design now consists of: Test pattern generator -> Scaler II (Dout is exported for analysis)

Test pattern generator is currently configured as 704x576 pix, RGB, colour bars.

The scaler is currently configured over control-interface to downscale to 176x144.

With this configuration, I get the attached uncompressed image.

In horizontal direction I can downscale 4 times, but anything below 240pix vertical dimension, corrupts the image.

This project was originally built in Quartus 13, sp1, using scaler v. 13.0.1

In that project I could scale to 176x144 without any problems.

Best Regards

Magnus Lauritsen

JT electric

[MLaur2]

Hi again,

I just figured it out.

The down scaled image requires more buffering. I guess this is due to reduced pixel-frequency by the horizontal downscale-factor.

My first solution was to insert a frame-buffer after scaling.