[LINK] Does NBN need a third satellite?

David Boxall linkdb at boxall.name
Tue Apr 5 08:59:00 AEST 2016


On 4/04/2016 2:04 PM, JanW wrote:
> ... My HD tv doesn't do MPEG4, evidently just MPEG2.
Decoding MPEG4 is substantially more resource-intensive than MPEG2. 
Unless your TV is very old, the hardware is probably up to the job. You 
might find that a solution is only a firmware upgrade away. Worth asking 
the manufacturer, at least.

 > So why did 7 network choose this? ...
MPEG4 is substantially more efficient than MPEG2. For comparable 
results, current implementations of MPEG4 take around half the bandwidth.

> My Kogan STB manages7Flix, so I can watch via that and/or record on it.
If you analyse recordings from several channels, you'll probably find 
substantial variation in the details of audio and video encoding. 
There's variation in MPEG2 DVB-T streams as well, but it seems more 
extreme in MPEG4 streams.

My remarks extrapolate from experience with DVB-S (satellite) streams. 
Bear in mind that, for those of us who rely on VAST satellite services, 
those new channels are not available. There simply isn't the bandwidth.

> ...
> Bottom line: not all compression is created equal.
> ...
Getting back to my original point, MPEG4 mitigates the bandwidth 
limitations. Sadly, it isn't enough. For comparable results, MPEG4 
halves the bandwidth. The best upcoming codecs halve that again. Our 
problem is that the market isn't for "comparable results".

The raw data in a UHD stream is about four times that in HD (without 
even considering extra loads like HDR). 8k is four times that again. 16k 
is four times more.

See the problem? Demand is quadrupling, while capacity is doubling.

We're very close to the limits of RF broadcast capacity. That's one 
reason why we really need to get moving on pushing fibre as far as it 
can go. How far it can go in the century-or-so anticipated service life, 
it's our duty to find out.

To put it appropriately, if a little crudely:
Time to extract the digit. ;)

-- 
David Boxall                    |  When a distinguished but elderly
                                 |  scientist states that something is
http://david.boxall.id.au       |  possible, he is almost certainly
                                 |  right. When he states that
                                 |  something is impossible, he is
                                 |  very probably wrong.
                                                   --Arthur C. Clarke



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