On terrestrial, a T1 mux only contains SD (or sub-SD) channels, and these
use the MPEG-1 codec. A T2 mux (PSB3 and, previously, COM7/8) contains HD
and a few SD, and *both* use the H264 codec.

On satellite it seems that rules are more relaxed: you can get HD channels
on an S1 mux and you can get a mixture of SD (MPEG) and HD (H264) in the
same mux.

Is there anything in the T1/T2 and S1/S2 standards which stipulates the
codec to be used and the fact that all channels must use the same mux? Is it just convention that terrestrial has no mixed-codec muxes?

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On 10/02/2023 09:42, NY wrote:

On terrestrial, a T1 mux only contains SD (or sub-SD) channels, and
these use the MPEG-1 codec. A T2 mux (PSB3 and, previously, COM7/8)
contains HD and a few SD, and *both* use the H264 codec.

On satellite it seems that rules are more relaxed: you can get HD
channels on an S1 mux and you can get a mixture of SD (MPEG) and HD
(H264) in the same mux.

Is there anything in the T1/T2 and S1/S2 standards which stipulates
the codec to be used and the fact that all channels must use the same
mux? Is it just convention that terrestrial has no mixed-codec muxes?

DVB modulation standards (T/2/S/S2) are agnostic I think regarding the
coding standards, which are a different layer.

People forget that DAB+ is a coding and not a modulation layer, which is
why DAB muxes can (and do) carry a mixture of DAB and DAB+ stations

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Yes its just data as far as the transmitter is concerned. As long as the receiver can tell the difference and decode them accordingly of course.
Looking at my old Pure the other day, there are now very few dab stations
out there compared with the plus. Do we think eventually, DAB will close all the old format stations down and use plus for everything?
Brian

--

--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Mark Carver" <mark.carver@invalid.invalid> wrote in message news:k4mjojFchkjU5@mid.individual.net...

On 10/02/2023 09:42, NY wrote:

On terrestrial, a T1 mux only contains SD (or sub-SD) channels, and these
use the MPEG-1 codec. A T2 mux (PSB3 and, previously, COM7/8) contains HD
and a few SD, and *both* use the H264 codec.

On satellite it seems that rules are more relaxed: you can get HD
channels on an S1 mux and you can get a mixture of SD (MPEG) and HD
(H264) in the same mux.

Is there anything in the T1/T2 and S1/S2 standards which stipulates the
codec to be used and the fact that all channels must use the same mux? Is
it just convention that terrestrial has no mixed-codec muxes?

DVB modulation standards (T/2/S/S2) are agnostic I think regarding the
coding standards, which are a different layer.

People forget that DAB+ is a coding and not a modulation layer, which is
why DAB muxes can (and do) carry a mixture of DAB and DAB+ stations

--- SoupGate-Win32 v1.05
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On 11/02/2023 11:07, Dave W wrote:

On Sat, 11 Feb 2023 09:52:34 -0000, "Brian Gaff"
<brian1gaff@gmail.com> wrote:

Yes its just data as far as the transmitter is concerned. As long as the
receiver can tell the difference and decode them accordingly of course.
Looking at my old Pure the other day, there are now very few dab stations
out there compared with the plus. Do we think eventually, DAB will close all >> the old format stations down and use plus for everything?
Brian

What do you mean "very few"? All BBC channels are still DAB.

<pedant mode>

Except for BBC Radio Cumbria, Jersey, and Guernsey.
All 64 k DAB+ Stereo HE-AAC v1

</pedant mode>

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On 11/02/2023 09:52, Brian Gaff wrote:

Do we think eventually, DAB will close all
the old format stations down and use plus for everything?

I hope so.
Though it won't be that great if we just get dozens and dozens of weird,
each only very slightly different, DAB+ stations all using 32 or even
24kb/s.

If the BBC DAB mux could change to DAB+ and keep the same bitrates then
they could, finally, again say truthfully that DAB is near CD quality.

--
Brian Gregory (in England).

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Brian Gregory wrote:

If the BBC DAB mux could change to DAB+

Previously that would have bothered me, as it would have killed-off my
Evoke3 at home and my older car radio. Newer car radio is now DAB+ and
Evoke3 has been retired in favour of internet streaming at home.

But I presume there's still plenty of non-DAB+ listeners out there?

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On 13/02/2023 11:00, Andy Burns wrote:

Brian Gregory wrote:

If the BBC DAB mux could change to DAB+

Previously that would have bothered me, as it would have killed-off my
Evoke3 at home and my older car radio.  Newer car radio is now DAB+
and Evoke3 has been retired in favour of internet streaming at home.

But I presume there's still plenty of non-DAB+ listeners out there?

In the words of Patrick Moore; 'we simply don't know !'

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