The "packed" format includes a sign bit (0x40) and a continuation bit (0x80) in the first byte, followed by the least 6 significant bits of the int value. Subsequent bytes (each appearing only if the previous byte had its continuation bit set) include a continuation bit (0x80) and the next least 7 significant bits of the int value.

In this way, a 32-bit value is encoded into 1-5 bytes, and 64-bit value is encoded into 1-10 bytes, depending on the magnitude of the value being encoded.