Encrypted linux partition data recovery

Greetings, I am hopeful there is someone here who is willing/able to help me with recovering data from a drive with 2 partitions. Partition 1 is encrypted, partition 2 is not and is 6.4 gb, partition 1 is the remainder of the 250gb disk. the drive has footage on it that was recorded from a zmodo surveillance dvr. Normally to view the footage on a pc you would plug a usb storage device into the dvr, perform an export from the dvr menu , then use a comverter to convert the files from their h.264 format to avi format.