The MHEG-5 specification does not prescribe any specific formats for the encoding of content. For example, it is conceivable that a Video object is encoded as MPEG or as motion-JPEG. This means that the group using MHEG-5 must define which content encoding schemes to apply for the different objects in order to achieve interoperability.
However, MHEG-5 does specify a final-form encoding of the MHEG-5 objects themselves. This encoding is an instance of ASN.1, using the Basic Encoding Rules (BER).