Sampling frequency on Radio programmes

Owen Smith owen.smith at cantab.net
Mon Apr 27 05:26:21 PDT 2015


They're converting from AAC to MP3 ie. from one lossy codec to another? Surely the audio quality loss caused by that will outstrip any sample rate conversion issues. Why can't they generate the MP3 from sample rate converted lossless?

-- 
Owen Smith <owen.smith at cantab.net>
Cambridge, UK

On 27 Apr 2015, at 11:09, Jim web <web at audiomisc.co.uk> wrote:

> In article <54ba6598cfweb at audiomisc.co.uk>, Jim web
> <web at audiomisc.co.uk>
> wrote:
> 
>> Afraid I don't know at present. But I'll inquire and see what I can find
>> out.
> 
> I've been told that the 48k -> 44.1k happens when acc is tapped out of the
> distribution cache and converted to mp3. That's then fed back though the
> cache and thence on to the user-facing servers. Apparently the general wish
> of the device makers was for this as a 'lowest common denominator' to
> maximise the number of 'legacy' devices that could accept the resulting
> shoutcasts. So aac -> mp3 transcode and the rate change are done in the
> same process.
> 
> In essence, AIUI it happens before the user-facing servers but after the
> aac generation.
> 
> As I think the French (almost!) say. "It's not magnificent. It's a railway
> station!" 8-]
> 
> Jim
> 
> -- 
> Electronics  http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
> Armstrong Audio  http://www.audiomisc.co.uk/Armstrong/armstrong.html
> Audio Misc  http://www.audiomisc.co.uk/index.html
> 
> 
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