Because the was getting quite long, and since a lot has changed to the algorithms djDecks uses, I think it is time for a new part.
When to report in this topic?
If you are using djDecks with vinyl control, and you feel that the pitch is fluctuating too much (with too much meaning that you can either hear strange sounds, or that it actually makes beat-matching more difficult) please report it here.
Please make sure that you are using the before reporting.
What to mention in the report?
-Which type of vinyl you are using (FS, SSL, VDJ, djDecks timecode or MsPinky)
-Are you using absolute or relative mode
-Type of needle, turntable and soundcard used, and if you are using phono pre-amps or not
-Results from callibration: Signal Strength and Pitch Variance
-Which Pitch Smoothing method(s) you tried, and what difference it made when changing them
-Which pitch detection method (on the debug tab) you used
-If possible, include the picture found in djDecks\settings\username\callibrate_1.jpg to your post
What are typical causes of unstable pitch?
-Dirty needles, make sure you clean them before reporting
-Vinyl that has been used very often. You can try to increase the lead in time to skip the first part of the vinyl.
-Not using phono pre-amps, which leads to a very weak signal level
-Interferences to the signal (ground loop, hum, ...) try a regular vinyl and use 'start line input' to listen if you can here anything wrong with the signal
-Using a mixer as phono pre-amp (turntable->mixer in->mixer out->soundcard). Some mixers distort the sound in ways that are not audible, but do make the timecode unreadable.
Picture of what the analysis picture should look like: