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Registered: ‎03-20-2019

Color Space Conversion VPSS dropping frames

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I am working on a design for a xczu4cg-fbvb900-1. I am using a Video Processing Sub-system in Color Space Conversion Only mode with Vitis 2020.1. It appears that it is dropping every other frame. Using ILA I am seeing TUSER asserted at the input as expected at every frame, but only asserted every other frame at the output. I am at a loss as to how this is happening, or what to look at to fix it.

This test case is converting from RGB to YUV422. Is there any reason that TUSER (frame start) at the output would be delayed by more than a line at the output? (I can only see about a line with the ILA)

Thanks,
Andy

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Explorer
Explorer
316 Views
Registered: ‎07-18-2011

 

andy.martin@videon-central.com 

Back-pressure comes from the back of the design towards the front, so the throughput is set by the AXI stream consumer of the data.   If it can't keep up with the producer of the data, it will take TREADY low and stop the pipe until it can catch up.

I've used the VPSS in CSC-only mode hundreds of times and have never seen that issue.

What is the VPSS driving?   A VDMA?

Are you running 1 pixel-per-clock, or 2PPC or more?  Does your AXI stream path have enough bandwidth to handle the data at the AXI clock rate?   Are the frame rate settings for your VPSS IP SW correct?

 

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Explorer
Explorer
317 Views
Registered: ‎07-18-2011

 

andy.martin@videon-central.com 

Back-pressure comes from the back of the design towards the front, so the throughput is set by the AXI stream consumer of the data.   If it can't keep up with the producer of the data, it will take TREADY low and stop the pipe until it can catch up.

I've used the VPSS in CSC-only mode hundreds of times and have never seen that issue.

What is the VPSS driving?   A VDMA?

Are you running 1 pixel-per-clock, or 2PPC or more?  Does your AXI stream path have enough bandwidth to handle the data at the AXI clock rate?   Are the frame rate settings for your VPSS IP SW correct?

 

View solution in original post

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Teacher
Teacher
305 Views
Registered: ‎06-16-2013

Hi andy.martin@videon-central.com 

 

It seems system issue.

Would you make sure your whole design and whether you set proper parameter and clock frequency or not ?

Also, to share your whole design is better way to get some useful suggestion.

 

Best regards,

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227 Views
Registered: ‎03-20-2019

@reaiken ,

Thank you for the advice. I found that there was another part of the pipeline that was stalling the video, and it made it look like the problem was the VPSS. Moving forward again...

Thanks,
Andy