You can analyze files in offline mode, but isn't the same file analysis made to a track when you load an unanalyzed track on a virtual deck during the dj set? (When you load a track on a virtual deck you can see the waveform being built, so isn't that the same thing as analyzing it when in offline mode?)

It will load the waveform but the autogain won't be set. You would have to reload the track in order to be completely analyzed if you do it that way. However sometimes this doesn't analyze the key correctly or the gain, so I recommend to analyze it in offline mode.

Ok - got it! Will the beatgrids be set when loading an unalyzed track on a virtual deck (while on the fly), the sane way it would when in offline mode?

By the way (I'm not sure if I should make a new thread for this question; but if yes please be so kind as to create a new one for me as I'm writing from my iphone..), concerning beatgrids:

Can you tell me how (or link a video, that shows how, if it exists) to customize beatgrids for older, or live, tracks that DON'T have a steady beat?

Most recently produced tracks (made with software) stick to the same exact bpm throughout the ENTIRE track. But, there are SO many tracks (e.g. disco, rock, jazz and so on, whose beats are "off". Is there a way of fixing this so that mixing, looping etc can henceforth be in perfect sync?

The ultimate, absolute best-case scenario, would be for Serato to automatically scan/analyze the entire track and create a NEW version of it where all beats would be in perfect sync. But, if that's not possible (intellectual rights of meddling with an original recording bla bla bla), maybe a "fixed" version only accessible/playable through sdj; that could rectify all "imperfections" (with regards to perfect mixing)? Something like serato flip does, in essence...?