Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Altera_Forum
Honored Contributor I
714 Views

CVI distortion

hi, 

 

I'm experiencing distortion in my VIP path where I'm mixing two video streams: 

 

TPG (800x600p RGB) -> MIXER_DIN_0 

CVI (640x480p RGB) -> FRAMEBUFFER -> MIXER_DIN_1 

 

The VIP chain is using a 50MHz system clock. 

The MIXER outputs 800x600p RGB 3 colorplanes(colorbars) in parallel @60Hz using a 40MHz clock. 

 

The CVI is clocking the 640X480 video stream inn using a 25.175MHz clock. The FRAMEBUFFER is setup for frame dropping/repetition. I'm pretty sure the 640x480 stream is correct prior to the CVI as I have clocked it out to a screen. However, when I provide the 640x480 stream to the CVI I'm getting distortion in the 640x480 overlay of the 800x600 video output. Can anyone provide som pointers here ? If this is timing related, how can it be fixed ? 

 

Saber890
0 Kudos
1 Reply
Altera_Forum
Honored Contributor I
43 Views

It seems I managed to figure this one out.  

 

The Framebuffer read/write masters were accessing the same DDR2 SDRAM memory locations as an deinterlacer was using.  

This was causing the strange patterns in the output video. I changed the memory location for the FrameBuffer and now the output distortion is gone. 

 

 

Regards,  

 

Saber890
Reply