Radio now aac rather than mp3

[Christopher Woods (CustomMade)]

> > Please do bear in mind though that (from my own empirical 
> comparisons) 
> > it seems the iPlayer just TRANScodes the original AAC audio to MP3, 
> > it's not encoded fresh from the original source audio.
> 
> Hi
> 
> Could you expand on the difference between the original 
> source & the original AAC.
> 
> I thought they were the same thing.


When I say "original source", I mean the original sound from source that the
BBC are using to do the main encodes. As far as I'm aware, they use the same
raw source feed as they send on to Sky Digital, Freeview, Freesat etc (there
was some discussion of this on the BBC Radio 3 HD Sound thread a while
back). From this, they also encode the iPlayer AAC streams for Listen Again.

The MP3 sounds like it's a second generation encode - i.e., it's being
TRANScoded from the main AAC file - and not being freshly encoded from the
raw source audio. If it is actually being encoded from the same uncompressed
feed that's being used for everything else, something is very, VERY wrong
with the codec configuration.

Martin Deutsch who used to frequent the BBC Backstage mailing list worked
for Siemens IIRC, he had access to some of the backend stuff and video/audio
archives, he may know if someone involved with the iPlayer team isn't
already lurking on this list :-) I've also discussed this on the BBC
Backstage list recently and provided samples, but that conversation thread's
dead for the moment (it really needs some input from people working on the
iPlayer team).