The audio codecs allowed for the "sndAc" element are not specified. There are many propietary and non-portable codecs which would break portability of a document.

Define a set of patent-free portable audio codecs as base. Whenever other codecs are used, the document must be marked as "extended" (see comment for Part 1, Section 2.6)

04/06/69 te

2994(3001)

Proposed Disposition of DIS 29500 Comment CO-0209 (Modified: 2008-01-03) The sndAc element does not specify the actual audio file which is used by the animation; as such, we do not believe that it needs a list of potential codecs. To clarify the semantics of this element, the following changes will be made in Part 4, §4.6.69, page 3,137, line 8: This element describes the a S s ound A a ction for slide transition. This element specifies that the start of the slide transition is accompanied by the playback of an audio file; the actual audio file used is specified by the snd element (§4.6.68).