Proposed Revision of the MPEG-4 Syntactic Description Language (Rev. 2.1)

Alexandros Eleftheriadis and Yihan Fang
Department of Electrical Engineering, Columbia University

Contribution M2902, 41st MPEG Meeting, Fribourg, Switzerland, October 1997

Abstract

This document proposes a minor revision to Section 7 of the MPEG-4 Systems Working Draft Version 5.1. The proposed changes are as follows:

  1. Indication that all binary quantities are with the most significant byte first, and the most significant bit first (Section 7.1).

  2. New rule (E.2) documenting the 'type(length) * name' syntax for look-ahead parsing (similar to the old nextbits() operation). This replaces the older notation that used square brackets and bitstring literals. The change is motivated by the significinatly simpler grammar rules that result, as well as the need to ensure the capability of using the syntax description for automatically generating both encoding and decoding code.

  3. Elimination of Section 7, Built-In Functions. At this point we are not aware of any request for special function support.

  4. Removal of BNF grammar section, which was previously Section 8 and was acting as a placeholder. A grammar is available (used in the Flavor translator), but is not included in order to reduce the length of the document. It can be made available and be included if the group deems it appropriate.

  5. Addition of references to publications related to the language, which provide more detailed (but also lengthier) documentation. Extension of the present description can also be done (to include, for example, the detailed scoping rules, as well as other semantics) if the group deems it appropriate.

The text provided below includes the entire section, with the suggested changes already incorporated.

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