about Chroma Resampler IP

[Altera_Forum]

hello 

 I use the Video and Image Processing IP core like this CVI(4:4:4)-> Chroma Resampler IP(4:4:4-4:2:2) -> CVO .When I use the Embedded Sync signals with CVI IP ,all work well.But when I use the separate wires Sync signals with CVI IP, the underflow of the CVO IP is high .  what's the problem ? Can anyone help me?

[Altera_Forum]

maybe you get also an overflow at the cvi? 

 Try to use a Framebuffer-IP. It seems that the output needs data, while the cvi is not sending data...