Bands in the exported gradient


I’ve a problem with the exportation of an animated gradient made with a blur and transparency effect. Fundamentally (in the exported file) the gradient appears as bands of colour. I’ve already tried every kind of exportation compressions but I haven’t found a real solution. I’ve noticed that whit a PAL compression I’ve a little improvement, but I don’t solve completely the problem.
The stranger thing is that in the rendering (inside the program) I don’t see this problem, but when I export all the video, it comes.

What do you think is the problem?

Here the animation with the problem

Toonbooms export to video is kinda ass and the quicktime exporter has a gamma ramp bug to boot.
You need to change your write node to something like png4 and render out a png sequence and then assemble it in another program like premier or sony vegas.

So is no way to do everything with toon boom?