In fine-tuning my options, I wanted to check I wasn't using too high (uses too much space) or too low (sounds bad) bit rate for recordings. My main use for get_iplayer is timeshifting for BBC Radio 4 Extra in the car. In the modes wiki https://github.com/get-iplayer/get_iplayer/wiki/modes it says:

• You may feel that 320kbps is unnecessary if you only record speech radio programmes
  

which makes sense and is why I use radiomode better (options) or radiobetter (WebPVR). But it got me wondering what actual bit rates are used by the BBC so searched and found this doc from the BBC - interesting for those with a broadcast / studio interest in general but also has in Appendix 2 the actual bit rates by station / platform they currently use http://downloads.bbc.co.uk/radio/commiss...nRadio.pdf
There's also a less detailed web page https://www.bbc.co.uk/sounds/help/codecs_bitrates
I'm not certain what governs which of the 4 Profiles is used, my guess is that this is negotiated between the device requesting the stream and the platform. Is that what the radiomode does?