Freeview Channel listings / bitrates

Mark Carver wrote:

Nonsense also. At 64QAM the payload is 24Mb/s, there's 50 there !
I don't think your card is measuring things correctly, I suspect the video
rates may absolute peak values set by the encoder for stat muxing, certainly
not typical, and nowhere near what the normal rates are. The audio data is
correct though, can't be varied dynamically.


These must be values transmitted as fields witin the SI data, the
BBC's figures, whilst extreme, look like the extreme upper limit for
statmuxing and can not possibly have been reached by bit-rate
measurement. The 4.35Mb/s given for BBC-1 in the original post
strikes me as appearing correct given that, in England, BBC-1 is not
statmuxed with other services. Intersting though the Welsh
measurments would appear to indicate that BBC-1W as part of a
statmuxed group. ISTR that S4C~ and S4C~2 are statmuxed into 6Mb/s
(which would include audio) before being sent to Crawley Count for
combination and up-linkng to the sat that distributes to the mux-A
trnsport stream to the txs.

ITV having an upper limit of 4Mb/s stikes true though, 10Mb/s is just
a porky though!

Rgds/Ted

In message ,
Ted Richardson wrote:

The 4.35Mb/s given for BBC-1 in the original post
strikes me as appearing correct given that, in England, BBC-1 is not
statmuxed with other services. Intersting though the Welsh measurments
would appear to indicate that BBC-1W as part of a statmuxed group.

I have a BBC paper here from some years ago (sorry, lost the url but
it should still be online somewhere?) which says that this is exactly
the strategy used. BBC1 (and the other channels?) are sent at a "high"
data rate (9Mbps) to the "nations" (Wales, Scotland, NI) and then the
whole multiplex is created at that centre as a complete stat-muxed
stream, rather than the English model where BBC1 is sent fixed rate as
part of a "ready made" multiplex so that it is easy to strip it out and
replace with local content when necessary, the other channels being
stat-muxed.

This also explains why BBC2 in England has no regional opt-outs, but
BBC2W and BBC2S and so on exist. The reason given in the paper is cost
- the equipment for producing a multiplex is expensive, and sending
"high" bitrate channels around the country is expensive.

In theory therefore there *should* be a perceived quality difference
between channels on mux 1 as received from an English transmitter and as
received from a Welsh (/Scotish etc.) transmitter, as the latter has the
whole lot to play stat-muxing with while the former does not. Can't
comment myself as I can't see a Welsh transmitter at the moment. Give me
six months and I might be able to do so.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... If there's one thing I can't stand, it's intolerance.

In message ,
Ted Richardson wrote:

The 4.35Mb/s given for BBC-1 in the original post
strikes me as appearing correct given that, in England, BBC-1 is not
statmuxed with other services. Intersting though the Welsh measurments
would appear to indicate that BBC-1W as part of a statmuxed group.

I have a BBC paper here from some years ago (sorry, lost the url but
it should still be online somewhere?) which says that this is exactly
the strategy used. BBC1 (and the other channels?) are sent at a "high"
data rate (9Mbps) to the "nations" (Wales, Scotland, NI) and then the
whole multiplex is created at that centre as a complete stat-muxed
stream, rather than the English model where BBC1 is sent fixed rate as
part of a "ready made" multiplex so that it is easy to strip it out and
replace with local content when necessary, the other channels being
stat-muxed.

This also explains why BBC2 in England has no regional opt-outs, but
BBC2W and BBC2S and so on exist. The reason given in the paper is cost
- the equipment for producing a multiplex is expensive, and sending
"high" bitrate channels around the country is expensive.

In theory therefore there *should* be a perceived quality difference
between channels on mux 1 as received from an English transmitter and as
received from a Welsh (/Scotish etc.) transmitter, as the latter has the
whole lot to play stat-muxing with while the former does not. Can't
comment myself as I can't see a Welsh transmitter at the moment. Give me
six months and I might be able to do so.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... If there's one thing I can't stand, it's intolerance.

In article , Martin Angove
wrote:


In theory therefore there *should* be a perceived quality difference
between channels on mux 1 as received from an English transmitter and as
received from a Welsh (/Scotish etc.) transmitter, as the latter has the
whole lot to play stat-muxing with while the former does not. Can't
comment myself as I can't see a Welsh transmitter at the moment. Give me
six months and I might be able to do so.

I can get a Scottish TX (Angus), but no English ones. so I can't compare
either! :-/

Is there a way to get a Nokia 221T to tell you bitrates, etc?

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Martin Angove
wrote:


In theory therefore there *should* be a perceived quality difference
between channels on mux 1 as received from an English transmitter and as
received from a Welsh (/Scotish etc.) transmitter, as the latter has the
whole lot to play stat-muxing with while the former does not. Can't
comment myself as I can't see a Welsh transmitter at the moment. Give me
six months and I might be able to do so.

I can get a Scottish TX (Angus), but no English ones. so I can't compare
either! :-/

Is there a way to get a Nokia 221T to tell you bitrates, etc?

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html