Why does my VIP Suite design in Qsys have timing errors between the frame buffer and the DDR memory?

To workaround this problem you can manually add the SDC file for the Frame Buffer of De-Interlacer core by going to the <quartus_installation_path>\ip\altera\<name_of_ip>, copying the .sdc file from this folder and adding this file to your project folder.  You will then need to add this SDC file to the list of SDC files that the TimeQuest Timing Analyzer evaluates when running timing analysis in your design.  This is done through the Assignments > Settings > TimeQuest Timing Analyzer settings.

This will be fixed in a future release of the Quartus® II software.