I told you the definition of data block is from DVD-Rom specifications.
So the block you got is the sector of DVD-ROM.
I think the block size is 2048 Byte.
You got the freeblock is 2295104
so 2295104 blocks should be 2295104 * 2048 = 4700372992 bytes
The capacity of DVD is about 4.7 Gbytes (1Gbytes=1000000000 bytes for decimal)
The other result is 4.377 Gbytes (1Gbytes=1073741824 bytes for computer)
4700372992/1048576=4482.6 M (you can see this result from Nero Disc info)