Podcast sample rate

[RS]

>From: michael norman Sent: Wednesday, July 26, 2017 13:37

>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.

Yes I do mean portable or MP3 players.  Thanks for the suggestion but the 
Amazon description of the Fii0 X1 is a good example of what I have been up 
against.  There is no indication in it of which file formats the device 
supports.

You want to play FLAC and OGG files from ripped CDs.  Several of the cheap 
players will play FLAC and OGG without problem.  I want mainly to play 
speech radio programmes from the BBC.  Some are available as MP3 podcasts, 
but most are delivered by get_iplayer as AAC .  That is why I find it 
frustrating when players claim to support AAC-LC but don't or don't 
properly.  It is not a question of price.  One person had a problem playing 
long AAC files with a Linn player, and I gather they sell for several 
thousand pounds.  The SanDisk Clip Jam has come down in price and is now 
about £25.  I have been very lucky in that SanDisk support has fixed the 
problem I had with AAC within about two months.

I thought my satellite receiver played AAC-LC files without problem.  I have 
just discovered that although it does start to play them it stops at a point 
which is repeatable for each file but is very different from one file to 
another.  For example the 320kbit/s Radio 3 recording of Prom 3, which 
includes the Schumann 2nd symphony you referred to, stops at 41min 27s.  The 
128kbit/s recording of the same Prom stops at 6min 31s.

It is not difficult to convert files to MP3, and MP3 has lot going for it, 
especially in terms of compatibility.  Quality from the latest LAME encoder 
is not far below AAC.  There are not many listening tests at high bit rates, 
but it is generally accepted that transparency, absence of audible artefacts 
no matter how difficult to encode the source material, is achieved with 
256kbit/s AAC or 320kbit/s LAME MP3.

>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 ?

There are extensions to AAC, called SBR and PS.  SBR is a more efficient way 
of encoding high frequencies.  As Vangelis has pointed out, if the player 
does not support SBR the high frequencies are lost.  PS is a different way 
of encoding stereo.  If the player does not support PS, all stereo 
information is lost.  10 years ago there was a need to reduce bit rates to 
save memory.  Players now have much larger memories.  I regard the 
extensions, together known as HE-AAC, as a retrograde step.  They are not 
used at bit rates of 128kbit/s and above.  I would prefer the BBC always to 
make a mode of 128bit/s or higher available rather than use HE-AAC.

As for the types of devices supported by the BBC, having a large number is a 
good thing because it results in a wider choice of modes from get_iplayer.