On 26/07/17 12:36, RS wrote:
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.
I have always used hardware players by which I assume you mean portable
players to listen to music. Those used to be called mp3 players
culminating in the iPOD I suppose. Nowadays I still do that and having
used various Cowon models in the past I now use a Fii0 X1. That one
costs around £99 plus memory card. Nowadays I imagine most people use
smartphones as general media devices and the market such as it is for
"mp3 players" has moved upmarket into its own niche. My Fiio device is
one of the cheapest options in that market. I only use it to play cds
ripped into flac or ogg and a very few mp3 I imagine if I put a some
radio programmes from GIP on it that it "should" play them, I haven't
tried that. Whether cheaper players like some on the Sandisk ones that
will do that I don't know. Neither do I know how smartphones perform in
this area for the simple reason that I don't have one.
The bigger question I suppose is how many devices can the BBC be
expected to support on for their content. Plus given that all of this
is a moving target who if anybody could produce a list of which BBC
modes work on which players ? Or have I missed your point ?
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.
I only have a vague idea of what SBR or even VBR means. is that an MP3
thing ? I only use MP3 when I can't get the content any other way.
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.
A question for the GIP developers ?
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?
See last coment.
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.
Listening abroad is not an issue for me, being in UK
For my use radio downloads are now 320kbits by default which suits me
given thar I have the bandwidth, I assume I could specify a different
mode if I needed to.
As you say if you listen to radio iPlayer via Firefox or any other
browser it doesn't offer a choice of bitrates. I think it should but
maybe that's one for the BBC.
Personally I'd like to see tv programmes offer the highest quality audio
as per radio, again one for the BBC ?
M
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