This register allows you to program the vertical subsampling factor of the first input color image in a batch of up to eight streams for memory based mode. This is also applicable for single stream in the stream based mode. Instead of sampling every line to calculate the histogram, the IP uses this register value to sample only specific lines of the frame. Valid values are 2, 4, 8, 16, 32, or 64. Typical value to be used is 16. To avoid processing errors, you should restrict the values written to this register to the range supported by the core instance.