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PCI Express*, Networking and Connectivity, Memory Interfaces, DSP IP, and Video IP
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VIP protocol: control packet after clipper

Honored Contributor II



i've got a question to the VIP protocol. In the control data packets of the Altera video streaming protocol there were some informaton like width and high of the videostream sent. I've got the following design: 

CVI (1280 * 720 pixels) -> FrameBuffer -> Clipper (192 * 128 pixels) -> own component 


In my own component I read the control data packet and there I get still a resolution of 1280 * 720 pixels. But why??? Shouldn't the clipper change the control data packet information to the current resolution (192 * 128 pixels)? 


Or did I get something wrong? 


Thanks for every hint! 


Best regards...
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2 Replies
Honored Contributor II

Ok, I think I found the answer on my own... 


It seems that the clipper first repeats the incoming control packet and then sends a new one (with the correct resolution) and the the video data...
Honored Contributor II

that's correct: 



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Additionally all other MegaCore functions in the processing pipeline must either pass on a control data packet or generate a new one before each video data packet. If the function receives more than one control data packet before a video data packet, it uses the parameters from the last received control data packet. If the function receives a video data packet with no preceding control data packet, the current functions keep the settings from the last control data packet received, with the exception of the next interlaced field type—toggling between f0 and f1 for each new video data packet that it receives. 


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the frame buffer and deinterlacer handle control packets differently, check the VIP Suite User Guide