[M4IF Technotes] What does AMR stand for? / Where's CELP

[Ben Waggoner]

Ralph,
    Yeah, clearly if one had to pick one ISMA codec, it'd be AAC-LC.  Still,
if streaming for a modem audience, CELP could have advantages over AAC-LC.
Alas, the QuickTime decoder doesn't seem to handle it, even though it is
mandated by ISMA.
Ben Waggoner <http://www.benwaggoner.com>
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on 3/13/03 4:37 PM, Ralph Neff at neff   PacketVideo.COM wrote:
> AMR is Adaptive Multi-Rate speech codec.
> 
> Regarding CELP, my interpretation is that low
> bitrate speech codecs are most useful in the mobile
> space, due to the low bandwidth and the fact that
> 2-way speech communication is a core application.
> But MPEG-4 CELP isn't specified by any of the mobile
> standards (e.g. 3GPP, 3GPP2).
> 
> Sure it's in ISMA, but the target application for
> ISMA (one-way multimedia delivery, wide range of content,
> transport via internet) makes generic audio coding
> (AAC) much more interesting/useful than speech coding.