The PiVideo software can be used within python for this purpose. First, make sure that you have installed PiVideo and can communicate with the PiCapture board:
pivideo -p i2c1 -q all
In your python program, you then use something like this:
Now you have an open communication port to the PiCapture processor, and can issue commands like:
Please note that you need to make sure that the port used for communication (I2C1, I2C0, or serial) matches the jumpers on the PiCapture and the code above.