In article , John Phillips
wrote:


From listening to Elgar's "The Dream of Gerontius" this evening
("simultaneous" on Radio3 and BBC4) my impression is that:

* The BBC4/DTTV audio level is much higher than the audio level on
Radio3/DTTV. After adjusting the levels I have the same impression
as Jim, but the comparison is too difficult to be sure (I have to
adjust manually on switching).

I also have the impression that the R3 DTTV sound is at a lower level than
the BBCTV4 sound. However I am avoiding switching back and forth as I want
to get 'complete' recordings for both enjoyment and comparison at a later
date! Hence I am comparing the 'live' sic TV4 with the 'rebroadcast' R3.
Since the R3 rebroadcasts are on at 2-4pm I wondered if they were 'daytime
listening compressed' in a way that the 'live' broadcasts are not. The
curio would be that applying something like 'optimod' would tend to lift
the level, yet it does seem lower on R3 to TV4 to me also...

* I cannot distinguish the audio on Radio3/DTTV from the audio on
Radio3/DAB (except that DTTV is more fragile from impulse
interference).

Is BBC4/DTTV broadcast at 256 kbit/s in comparison to 192 kbit/s on
Radio3/DTTV and Radio3/DAB?

I have also been wondering if the bitrates differ. Also, since the R3 DTTV
is on a different mux, if this is 'reprocessed' in some way at a point
between the BBC and the actual transmitter(s). IIUC repeatedly
expanding-compression mpeg-like streams has a detremental effect just like
repeated conversions to-from jpeg.

FWIW I have been given the name of someone at the BBC who may be able to
answer some of the questions I have, so will investigate. If I find out
anything useful I'll report back.

Slainte,

Jim

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