Video flickering using DMA Controller with D5M on DE2i-150

I'm having trouble when using DMA Controller to buffer video stream captured from D5M on DE2i-150.

The video will get flickering if I buffer video over 320x240x16bit resolution. However, 160x480x16bit resolution works fine.

I think the problem associates with the RAM, both SDRAM and SSRAM. I can't find a configuration for these RAMs to get it work.

I wish to make it works at 640x480x16bit resolution.

Results from buffering with 320x240x16bit

https://alteraforum.com/forum/attachment.php?attachmentid=13675&stc=1

Results from buffering with 160x480x16bit

https://alteraforum.com/forum/attachment.php?attachmentid=13676&stc=1