>>> why can't the player store the actual profile in a temp-file and restore it when the track is played again?


There are 2 reasons for this -> 1) Only a fixed number of variable data bytes are allocated to each track 2) The discs are mounted read-only except when synchronising with Emplode.

Whilst the profile for a track is being generated it takes up a lot more space than the completed profile. This is because for every new sample in a currently playing track it needs to calculate new means and standard deviations, and also to recalculate the number of standard deviations each already measured point equals now that the new sample has been added to the set. Once the profile is complete it can be compressed down to 2 bits at 128 pixels width = 32 bytes.

Your method of storing the partial profile in a temporary file would be feasible for the situation where you start profiling a track, power off, and power back on again to resume the profiling. It would not be feasible in a system where you are constantly changing tracks without finishing playing them as this would involve temporary storage to be allocated for an arbitrary number of tracks.

Please keep the ideas and questions coming.
Toby