Sent: Thursday, July 20, 2017 12:56 I wrote
To: get_iplayer@lists.infradead.org
Subject: Re: Podcast sample rate
I wish the BBC would think more about backwards compatibility of AAC.
There is no problem with software players. HTML5 and recent versions of
VLC fully support HE-AAC v2 with LC (Low Complexity), SBR (Spectral Band
Replication) and PS (Parametric Stereo). The problem is with hardware
players.
I am not alone in this list in having had difficulties playing AAC-LC at
all. When trying to find hardware players which support SBR and PS the
problem gets worse.
Obviously what I would like the BBC to do is off topic. Even so, I hope I
will be forgiven for saying that I would like to see a move towards at least
128kbit/s stereo audio in preference to adding SBR.
What I would like get_iplayer to do is to include in the documentation a
warning of the perils of SBR for players which do not support it and to
include in the table in
https://github.com/get-iplayer/get_iplayer/wiki/modesref
an indication of which modes use SBR and which do not.
Is the table up to date? For HVF 50fps modes it shows the audio bit rate as
128kbit/s or 320kbit/s and for HVF 25fps modes other than HVFlow it shows
the audio bit rate as 96kbit/s or 320kbit/s. I have not used the 50fps
modes but I have occasionally used HVFxsd. I have not seen 320kbit/s audio.
Which programmes use it?
Is the radio table up to date? I thought I had seen somewhere that there
had been a relaxation of the 96kbit/s maximum bit rate when listening
abroad. I can't find anything about it on the BBC's website. This page
https://www.bbc.co.uk/iplayer/help/Mobile_abroad
tells me under the heading, "Can I listen to radio abroad?"
"You can also listen to BBC radio outside the UK from a desktop computer at
www.bbc.co.uk/radio."
There is no mention of bit rate. If I go to that page in Firefox it does
indeed play the programme I select, but it does not offer me a choice of bit
rates, but automatically plays at 320kbit/s. I have not tried doing it
abroad.
Interestingly that 320kbit/s bit rate means the radio iPlayer offers the
highest bit rate of any mode of delivering radio programmes. Television is
the poor relation in comparison. Many broadcast programmes include a
256kbit/s AC3 stream, but for most modes the iPlayer does not offer anything
better than 96kbit/s stereo.
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