So I have a batch of .mov files that are camera flashes on on an alpha background. When play the video file on my PC it plays fine with either a white or black background for the alpha layer. When I import it to AE it turns to a yellow background with no alpha. When I export it or place it into a comp it retains the yellow colour.
Other .mov files have just changed colour in AE, ie. backgorund loop videos swap from gold to blue.
I am using AE 2015.3 on a Windows 7 Professional 64 Bit PC. Usually render through AME but have tested with AE Render also.
Right click on the footage in the project window and select Interpret footage > main and there you can set how AE interprets the Alpha. Should default to the right setting, but it's worth checking. Maybe you can fix it there.
there has been a problem recently ever since the new 13.8.1 version that supports native encoding and decoding of some QT codecs. try clearing your cache from the preferences. more information here: Re: AE 13.8.1 BUG native QT png support