Colors are screwed up after export / import h264/avc

Question

Assume we have created some raw colors with AE. And exported the file with h264/avc codec (see the picture).
I understand that exporting with chroma 4:2:0 can change the colors a little. It's ok. We play the file with local video player, RGB values are 1-2% away from original, it's not critical.
But what I don't understand is - why re-encoding the file to h.264/avc with Adobe Media Encoder as standalone application leaves all the colors 100% correct, but if I will import the file to Premiere or AE, colors are visibly screwed up?
Then export composition to h264/avc with the same settings as stand alone encoder and the colors are screwed up one more time by 1-2%!
Am I doing something wrong? How to keep the colors when importing?

Answer 1

Either the good old H.264 Gamma problem or simple quantization errors which you might probably avoid by working in 16bpc or 32bpc. Also keep in mind that AE can use color management and you may already see those differences when setting the comp viewer proofing to you monitor profile. Generally, though, such color issues are extremely difficult to track down. Things like your graphics hardware's acceleration features, VLCs selected decode method, color profiles and other color tweaks can influence this, both in mere perception of colors as well as actually skewing them. Start by working in higher bit-depths when re-importing files into AE and tippi-toe your way to the aforementioned color management stuff and so on...
Mylenium