2.2.3.4 Envelope Encoding Record

Envelope Encoding Records are the Property Records that define the encoding format that is used to encode the message envelope in subsequent Envelope Records. Such records come in two forms: Known Encoding Records and Extensible Encoding Records.

In messages, this record shows as variable-sized so that it can be either of the two forms. If the record uses Known Encoding, it is fixed-sized; otherwise, the record is variable-sized.