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6.1.3. Interfacing with Serial Digital Interface (SDI)
The SDI-clocked video interface deals in the SDI symbols, not the video samples. This means that only certain of the SDI mappings are directly compatible with Avalon-ST video requirements. The figure below shows the 8- and 10-bit YCbCr 4:2:2 mappings.
You can transport other mappings into the Avalon-ST domain but to rearrange the samples into a compatible format, immediate remapping into the Avalon-ST format is required. The clocked video units do not perform any remapping function.
If a single pixel configuration is used, then the horizontal resolution would be correct in the Avalon-ST control packet. If the 2 pixel solution were selected, the Avalon-ST control packet would report a width 2x the actual horizontal resolution (since an entire extra line is carried on Link B but it’s pixels would be counted as part of Link As). In both cases, the Avalon-ST control packet would report a vertical resolution ½ the actual resolution since 2 lines have been handled as 1. Any remapping logic has to account for this.
In this case using 1 pixel, 4 color planes in parallel will mean that the control packet reflects the true dimensions of the incoming image. If 2 pixels with 2 color planes is configured, then the control packet will report a horizontal width 2x the actual width.
The 12-bit data mappings also require processing to recombine the relevant SDI symbols into the correct pixel components.
If you select 2 pixel in parallel configuration, then the control packets from a CVI will report 2x actual width. Going into the CVO, the packets would need to report 2x the actual width.
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