64-bit integers encoded into a 7-bit string.

The low 7 bits of each byte represent the data, and the high 8th bit represetns the continuation bit. If the continuation bit is set, then the data continues in the next byte. You keep going until the continuation bit is clear.

Example pseudocode:

Uint64 result=0;
Byte b;
do {
	result <<= 7;
	result |= b & 0x7f;
} while ((b & 0x80) == 0x80);