Is there a filter to keep contrast the same throughout a scene?

[Master Tape]

With certain videos on my Panasonic HS-860, the contrast of the image keeps going up and down depending what is on screen. And it's especially noticeable when it goes from white to black in the next shot and it pumps the blacks up brighter for a second before settling down.

Is there not a filter that can maintain the same contrast throughout, so the levels wont fluctuate?

[jagabo]

In AviSynth ColorYUV(autogain=true) works pretty well with the whiteout sections.

LWLibavVideoSource("Example.avi") 
AssumeTFF()
src = last

SeparateFields()
ColorYUV(AutoGain=true) # apply automatic gain
ColorYUV(gain_y=-20) # set a nominal white level
Weave()

StackHorizontal(src, last)
QTGMC()
HistogramOnBottom()

[Master Tape]

That's sorted it, thank you