MPEG-2 Transport Stream and Speex Audio

Are there any efforts underway to standardize the multiplexing of
Speex Audio within an MPEG-2 transport stream?

More generally, I'm looking at audio formats available within MPEG.
If my understanding is correct, it looks to be limited to Dolby
Digital (via ATSC Document A/52B), MPEG-1 Layer 1-3, MPEG-2 audio, or
a variant of AAC audio.

Specifically, I'm looking at efficient ways of encoding speech which
correlate with video.

A Programmer wrote:
Are there any efforts underway to standardize the multiplexing of
Speex Audio within an MPEG-2 transport stream?

While I don't know, I doubt it. Standardization of MPEG-2 is, AFAIK,
complete, and efforts go into the extension of the MPEG-4 specs. IIRC,
MPEG-4 included an optional speech codec, but please don't ask me for
details.

So long,
Thomas