The frameTime and blockTime parameters can be set to any value. However, if the requested time would cause the number of samples per frame or frames per block to exceed the allocated array sizes in the code, a message to this effect will be printed and the program will end. The array sizes can be increased by changing the values defined at the top of vis_main.h and recompiling.
The minimum filling fractions (minFrameFill, minBlockFill) specify the minimum fraction of good data within the specified frame or block time. This calculation is done in terms of the number of good items in the next lower processing level. For example, minFrameFill = 0.5 means that one half of the samples within the frame must be good. At the block level, all frames are counted equally towards the minBlockFill.