I'm using a a custom particle I made with series of Photoshop brushes shaped like clouds. Each brush shape is set to one frame. Particular is sampling each frame randomly for the particle. I'm trying to look like your flying through a bank of clouds.
What is happening though is I'm getting clouds that fly by but are stuttering in size. It is almost as if the frame sequence instead of being the normal "1, 2, 3, 4, 5, 6...etc" it is "1,2,1,2,3,2,3,4,3,4,5,4,5,6, etc..)
Is there a way to correct this? I'm looking at CC Time Blend but if I can fix what my issue is in particular I would be much happier.
Perhaps those shapes aren't so perfect that they would create smooth animation of cloud shape.. Foor smooth animation, if we assume that differences between each two sequential frames are minor, even then do ccTimeBlend for that cloud sequence, or at least do timeRemapping with frameBlending ON. Latter method is good in way that you can easily control speed of cloud's shape shift.
If no success, then post some visual info of what you have, to see what are the real causes of your misfortune. :)