The run-time requirements for encoding are substantially depending on the desired usage. To point this out it is helpfull to compare the encoders requirements for broadcasting and for DVD-Video production.

Example: Broadcasting: Within a production chain for a live transmission the efforts for encoding may not exceed a specific delay time. To avoid synchronization problems this has to be regarded for both audio and video. Both signals must be coupled together before broadcasting. Procedures matching this requirements will be called real-time or synchronous processes.
Example: DVD-Video: The encoding time is not important for DVD production, it may take much longer than for decoding. Only the contrary aspects quality and financial expenditures has to be regarded. As the time conditions for encoding and decoding are totally independend, procedures of this categorie will be called asynchronous processes. The example DVD production covers both time conditions and complexity of the algorithm (system performance).

Equivalent effects occur for a variety of compression procedures and are not restricted to multimedia contents. In most cases a proper compression efficiency is more important than savings for the encoding process. This a principal characteristic for any 1 to N communication, that is one single object is frequently used for many purposes (e.g. downloads).

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