FrameBuffer/ memory arbitration problem

Dear all,

I have been banging my head solving this problem with my custom frame buffer and have no idea whats wrong.

Basically I have designed a simple 3 frame,frame buffer with an av-st sink and av-st source.

The AVst-sink simply takes Video IP packets received and writes them frame buffers in memory using the Av-mm port( which was designed using alteras template av-mm master), if the frame buffer is not being read from.

The Avst-source port however on the other hand, reads a frame buffers twice (2 fields) in sequence if its not being written to.

All the transaction between read and write seems perfectly fine. In signal tap I have not seen even once where the frame buffer controller reads and writes to/from the same frame buffer in memory.

However I still get corrupt data stored on one of the frame buffers.

Any ideas what can be wrong.