Podcast sample rate

RS richard22j at zoho.com
Wed Jul 19 08:41:11 PDT 2017

>Sent: Wednesday, July 19, 2017 14:13  I wrote

>The answer seems to be that some programmes do use SBR and some don't. 
>Recent studio and outside broadcast programmes seem to use AAC-LC so there 
>is no SBR and the 48kHz sampling rate is preserved, although at least some 
>of the Wimbledon coverage had SBR.  A few weeks ago there was a repeat of a 
>Talking Pictures programme on Lord Olivier and that had SBR.  When older 
>films are made available on the iPlayer some use AAC-LC and some have SBR.

The programmes which I identified as using SBR were probably downloaded 
using hvfxsd5.  I have downloaded some of the programmes which I had 
previously downloaded with hlshd1 and found to use AAC-LC.  This time I used 
hvfxsd5 and the programmes did have SBR.

As far as I can see at present the rule is
hlshd1      96kbit/s AAC-LC and 48kHz sampling rate
hvfxsd5    96kbit/s HE-AAC v1 with SBR and 24kHz sampling rate for players 
which do not support SBR

One exception I have seen is the red button coverage (not the highlights) of 
the Olympics which I downloaded with hvfxsd or its HVF equivalent at the 
time, but that may have been from a different CDN.  I have not tested 
widely, and I have not tested other modes or CDNs other than Akamai. 

More information about the get_iplayer mailing list