Best Codec to EXPORT a D90 movie ???
I doubt it is your D90 degrading. The D90 uses a rolling shutter to take video, so when you pan quickly any vertical line that you have will seem to wave and have jagged lines. You have a lot of vertical lines.
If you want want to take good video, you need to study how to do it. It is different than still photography.
The reason I say degrading is because when I first got the camera and up until around Thanksgiving or Christmas the videos looked fantastic. No adjustments have been made to shooting settings. Doesn't matter if its a Nikon or a 3rd party lens, VR on or off. The videos had a real nice quality to them for the first few months. Now with whatever I shoot, the videos look jagged and as if you are seeing doubles. As seen in my videos on my Youtube.
It even does that shooting my 9 month old daughter here in the house.
Of course I could send it to Nikon, but they would find nothing wrong with it, or it would be within spec I'm sure. However, there is clearly a problem with the sensor. It doesn't just go from great looking videos to awful videos on its own.
My D90 settings haven't changed since the day I first got it and set it up, it hasn't been dropped or abused. Sensor gets dusted with a rocket blower regularly. In general, I take very good care of my equipment.
Kingston, ON, Canada
D90, Tamron 17-50 f/2.8, Sigma 70-200 f/2.8, SB-600