Different look of video in realtime compared to rendered.

[pyc]

I've been scratching my head the whole day, think I soon will hit the wall if it doesn't get solved..

Well... Video that I've been rendering looks significantly different when rendered compared to what I see when I make it. Yes, the video is very demanding and specific, but if I render in maximum quality outputting PNG stream of lossless pics, it should look absolutely the same right? But it just doesn't.

It's a "tunnel", some stuff that is reacting to music with colors and zooming in and out, but the final effect is Trails which gives nice tunnel-like effect. Thing is, in the middle of the tunnel, in rendered version, everything is bright, almost like a constant bright circle, but when I watch it in realtime in Magic (with fps of about 15-20) it's a whole lot of different story with every detail in the center. I don't know is that some kind of compression that ruins the video or what, but I don't even know how can I output greater rendered quality.

Please tell if you know what it's all about. Thanks!
Take a look at the screenshots.

[Magic]

Trails (and some other effects) render differently at different frame rates. If you are exporting at 60 fps, then you should try to get your Magic window to run at 60 fps. Or, don't rely on what the Magic window looks like. Instead, export small preview movies so you can see what the final result will look like.

[pyc]

That helped a lot, thanks!