System Considerations - 5.2 English

PG243 Video Mixer

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5.2 English

The Video Mixer must be configured for the actual input and output image frame-size to operate properly. To gather the frame size information from the image video stream, it can be connected to the Video In to AXI4-Stream input and the Video Timing Controller. The timing detector logic in the Video Timing Controller gathers the video timing signals. The AXI4-Lite control interface on the Video Timing Controller allows the system processor to read out the measured frame dimensions, and program all downstream cores, such as the Video Mixer , with the appropriate image dimensions.

Another system consideration that needs to be taken into account is that there is sufficient bandwidth available to the Video Mixer to maintain proper functioning memory layers. The bandwidth needed (in MB/s) for a memory layer can be calculated with the following equation:

Bandwidth (MB/s) = fps × height × stride

Where fps is the number of frames per second the Video Mixer is operating at, height is the height in lines of the layer, and stride is the stride in bytes of the layer.