System Considerations - System Considerations - 1.2 English - PG325

The Video Multi-Scaler IP must be configured to operate properly. There must be sufficient bandwidth available for this IP to function properly.

• You can calculate the bandwidth needed (in MB/s) for a memory layer with the following equation:
  Bandwidth (MB/s) = fps x height x stride

  Where:

  • fps is the number of frames per second the Video Multi-Scaler is operating.
  • height is the height in lines of the image.
  • stride is the stride in bytes of the image.

  For example, for a 2 output 3840x2160@30 RGB 8-bit input and output video, the bandwidth requirement is calculated as:

  S1 (Source Bandwidth for out1) = 30 x 2160 x 3840 x 3 = 712 MB/s
  D1 (Destination Bandwidth for out1) = 30 x 2160 x 3840 x 3 = 712 MB/s
  T1 (Total bandwidth of out1) = S1 + D1 = 1.39 GB/s
  T (Total bandwidth of the system, that is, for 2 outs) = 2 x T1 = 2.78 GB/s
• The clock required to achieve the performance is calculated as follows:
  Number of pixels operated for an Output = max(input width, output width) x max(input height, output height) x frame rate
  Number of pixels operated by all Outputs: Pix_total = Summation of number of pixels operated for an output
  Minimum clock required to achieve the performance = Pix_total/Samples per clock

  The actual clock in the design needs to be approximately 10% higher than the minimum clock requirement.