check these tables
TB_PT_"your process name"
It's all what i've found.
Those are definitely the tables used to store process data. And the playback mechanism _might_ use them for data to display. But they have no bearing on the actual recording data.
I had to experiment a bit to find the storage location myself.
On JBoss on Windows (on my specific installation), the recording information is stored here: C:\Adobe\LiveCycle8.2\jboss\server\all\svcnative\DocumentStorage\audit\workflow
There are subdirectories for each run, named after the process instance id, and everything seems to be stored as XML files.
So there it is. Now that I know, it may not be helpful information, but I can share it so it's not helpful for everyone!
To update and clarify my answer, the audit/playback files are stored in the Global Document directory. If that's undefined, as in my example on my machine, it goes into the default folder. If the AdminUI has been used to defind a Global Document Store directory, they go there.