DASH and HAF mode sizes

[RS]

Budge recently had a radio problem which he said was solved by using HAF 
modes instead of DASH.  That prompted me to install v2.97, which I have 
resisted up to now, to try HAF modes, although I suspect HAF modes are just 
a v2.97 new name for v2.95 HLS radio modes.

The pid I am looking at is b08cq5xm.  --info displays the mode sizes for 
original as
dashhigh 55MB
hafhigh 73MB
dashstd 22MB
hafstd 29MB
dashmed 16MB
hafmed 22MB

According to
https://github.com/get-iplayer/get_iplayer/wiki/modesref
dashstd and hafstd are both 128kbit/s, so it is not clear why the file sizes 
should be different.

What is the difference between DASH and HAF?  (I have just spotted that in 
the latest wiki dashstd has become dafstd, so we have yet another mode name 
change between versions.)

I have compared the file sizes from hafstd1 and dashstd1 and they are both 
23,236,978 Bytes.

For the podcast the flashaacstd1 mode size is given as 269MB, which seems a 
bit unlikely, so maybe the arithmetic has gone wrong.

Budge’s problem was said to be connected with v3.2 of ffmpeg, and fixed in 
v3.2.2.  The Windows installer for v2.97 (running in Windows 10) does not 
seem to have updated ffmpeg.  The version I have displays ffmpeg version 3.0 
when it runs, as it did for v2.95, and the date is 18-Feb-16.  According to 
http://ffmpeg.org/releases/ the date of v3.2.2 is 2016-12-06.