[opendtv] UK HDTV results

  • From: Dermot Nolan <dermot@xxxxxxxxxxxxxxxxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Tue, 28 Nov 2006 17:27:05 +0100 (CET)


I thought you might be interested in this URL: 
http://www.bbc.co.uk/info/policies/pdf/dtt_hdtrial.pdf , detailing the results 
of the current MPEG4 DVB-T HD trials in London.
I have recently been watching the tests on  a Sony VAIO laptop with very 
interesting new software from Nebula electronics (www.nebula-electronics.com) 
which supports the H264 DVB-T transmissions and can be used with any Microsoft 
BDA TV driver. I am using it with a Hauppauge WinTV HVR 900 DVB-T stick (the 
Nebula software works with any DVB-T stick using BDA such as Hauppauge. Having 
adjusted the video display options using the sophisticated Nebula software I am 
able to receive flawless HD pictures on a widescreen VAIO laptop. I think the 
software cost me about £70. The software provides a wealth of information: the 
SNR at my location is 28dB about 12 miles away using a rooftop antenna (ERPs 
are 5kW for the BBC HDTV stations and 1.5kW for the commercial HDTV channels 
sharing a multiplex: the range of the service is quite big although it doesn't 
match the Freeview stations at 20kW. Naturally the Nebula switches seamlessly 
between the HD transmissions and the Freeview MPEG2 stations. It also has a 
full 7 day EPG, built-in PVR and capability to burn recorded transport streams 
to DVD. Neat. The HD streams appear to be running at 20Mb/s for widescreen 
1080i, there is some disappointment with the current efficencies of MPEG4 
encoding which doesn't deliver on its promises, and a full commercial service 
probably depends on analogue TV shutdown, spectrum availability and a DVB-T2 
which is currently being defined. More efficient coding schemes are being 
considered by the BBC et al: watch this space. The transmission parameters 
appear to be 8k 64QAM, ie around 24 Mb/s in an 8Mhz channel.
This little purchase enabling MPEG4 HDTV on a laptop with a conventional DVB-T 
stick shows how far the industrialisation of the DVB-T system has come compared 
to its rivals. It did not surprise me that the Phillipines chose DVB-T in 
preference to ATSC: the commercial flexibility and pace of product development 
says it all. I haven't seen any reception problems in the HDTV services 
although, of course, there are encoder errors from time to time: inevitable 
with an experimental service.

In the evenings the BBC is showing a lot of dramas made in HDTV, some 
simulcasts eg 'Strictly Come Dancing' and 'Robin Hood', live in HDTV, ITV 
appears to be showing films, and the others are showing US HD imports such as 
Desperate Housewives and Lost. 

Kind Regards,

Dermot Nolan

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