Making fluid transitions between arbitrary parameter changes can be annoyingly difficult.
This CHOP reads an input value for changes, and every time a change occurs, it will write the value to one of two
output values in alternating fashion. It also outputs a "cross" parameter which can tell which of the output values
to read.
For example, you could set up two Video File In TOPs. The first will have a parameter bound to CHOP_FlipFlop's output
value 1. The second will have the same parameter bound to CHOP_FlipFlop's output value 2. Plug both Video File In nodes to a
Cross TOP, and bind the "cross" parameter to CHOP_FlipFlop's "cross" output. Make a single slider to control
the real parameter value, and bind that to CHOP_FlipFlop's input parameter. Every time the slider changes, you will now get
a fluid transition from one state to the next.