Intel® FPGA Streaming Video Protocol Specification

ID 683397
Date 5/15/2024
Document Table of Contents

2.2.8. Multiple Pixels in Parallel and Empty Pixels

The Intel FPGA video streaming protocol does not use the AXI-S TKEEP or TSTRB signals, so all bytes within a packet are valid. Where video lines are not an integer multiple of the numbers of pixels in parallel, and empty pixels exist, the final beat of video packets is padded with unused data.
Figure 31. End-of-field pixel packing 4 pixels in parallel, 30 bit YCbCr, empty last pixel. The figure shows an example 4 pixels in parallel system where a line of 1920x1080p HD video has had the final pixel cropped and is now 1919 pixels wide. The final beat of the packet (beat n) is padded with unused data.

Padding because of empty pixels always occurs in the last beat of the packet. The first beat of the packet is always full of pixels, apart from the case of very short lines where the first beat is also the last beat. In the full variant of the protocol, the expected width of each video line is transmitted via image information control packets and so a receiving IP disregards the top bits of the final beat of the packet.