Re: [AVT] Common Format: draft-ietf-avt-evrc-07, draft-mathai-avt-smv-00, Purevoice, etc.

Is it useful to have a common format for EVRC and SMV and possibly other 
codecs?  This probably depends on sub-questions: Are there likely to be 
implementations which must support multiple codecs?  Is it simpler for such 
implementations if the formats are identical?

If it is useful to have a common format, is it harmful to have multiple 
formats for the same codec?  If so, we probably want to roll the current 
EVRC and SMV drafts into the new common one.

As for MIME registration, it occurs to me that we may be able to have one 
new MIME type for the common format, with a parameter specifying which 
particular codec is being used.  For example, "audio/foo; codec=bar".  The 
common format specification can include in the IANA Considerations section 
instructions on registering new values for the codec parameter for future 
codecs which want to use the common format.  Presumably such registration 
would include the mapping between frame type and frame length, which 
hopefully would be about the only difference from one codec to another.

Making EVRC and SMV use the same format is probably an easier question than 
including PureVoice as well, and so should be discussed separately, I think.

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