It's likely related to your source video. What type of camcorder is your video coming from and how did you get it into your computer?
MPEGs and VOBs are notorious for causing uneven effects because of the compression system they use. Especially when they're used in a project that hasn't been set up for their video format.
Thanks for your reaction., but sorry, this cannot be the correct answer.
First, the title has nothing to do with the video (source, camera, etc.).
Second, the problem appears also in the AVI-format.
Or am I wrong?
There was a Bug with Transitions, and the trick, IIRC, was to alter the fixed Effect, Opacity (automatically appears for every Video Clip) to very slightly less than 100%. This is done by selecting the Clip/Title, and then Effect>Edit Effects. This brings up Motion, Opacity, Rotation, etc.. In Opacity just adjust to about 99% from the default of 100%. That seemed to fix a flash in the Transitions for that Clip.
Let us know if this works in your case - hope I remember this one correctly.
This works! And it's quit easy to copy and paste this Attributes to other titles.
Exists this bug still in the later versions of PE?
Glad that my memory is not as failing as my eyesight, and that I got the "trick" correct for you.
Actually, PrPro had a similar Bug with CS4 (?), where one needed to add a Keyframe in Opacity. It did not need to be altered in any way, like PrE, but needed to be added.
As for PrE 8, I do not recall seeing any recent posts on this issue. My guess would be that it was fixed in PrE 7, and was not broken in PrE 8, but that is just a guess.
Good luck and happy editing,