could simple-openni track users on pre-recorded data?

[Guang Zeng]

I have a recored oni file. I didn't turn on "enableUser(); " when I record the oni file.
Now I want to track users in this oni file. When I turn on the "enableUser(); ", I got an "Couldn't getXN_STREAM_PROPERTY_PARAM_COEFF" error.
Now I have two questoions
1. So simple-openni could not track users on pre-recorded data if "enableUser(); " is off, am I right?
2. Could I get user data if I turn on "enableUser(); when I record the data?

Thanks!