Barry and Neil - watch Playsounds video it explains it very well.
Playsound excellent video showing the problem being experienced ! Does this happen on all your vid. clips no matter what format they are?
Marina, I tried to reproduce the pixelated colors using different format clips such as .mt2s, mp4, mov, wmv, even a still png - but no luck getting the pixelation you both are experiencing. I did not have an mpeg2 video clip to experiment on.
It might be the specific mpeg2 video you are trying to brighten and / or your video card. What video card do you have?
Also what version of PD are you using? I am using the latest beta patch v2923 (there is an official patch out right now v2930 - but I have not installed that yet.)
If you or Playsound would like to attach a 5 - 10 second video clip of your trouble file for us to play with and see if we can reproduce the issue on our different computer hardware then that would help to narrow things down a bit.
Rob
PD 14 Ultimate Suite / Win10 Pro x64
1. Gigabyte Brix PRO / i7-4770R Intel Iris Pro 5200 / 16 GB / 1 TB SSD
2. Lenovo X230T / 8GB / Intel HD4000 + ViDock 4 Plus & ASUS Nvidia 660 Ti / Link: https://www.youtube.com/watch?v=ZIZw3GPwKMo&feature=youtu.be