[opendtv] Re: BBC DTT HDTV trials
- From: "Nick Kocsis" <kocsis_nick@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 12 Feb 2007 17:45:13 -0500
Interesting report indeed ! However it must be given a careful reading.
Comments favouring a view harmonizing with one's techno-political bias can lead
to unwarranted conclusions.
The tests actually extended into October 2006. Given the recording, analysis
and preparation time required before presentation, the report was likely tabled
no earlier than November 2006. The stated intention is to do further testing
at a future date (seems to me we heard that one before years ago from the ATSC
consortium and we are still waiting for it !) One would be wise to hold
judgement until such tests are conducted and tabled.
----- Original Message -----
From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Monday, February 12, 2007 12:44 PM
Subject: [opendtv] BBC DTT HDTV trials
http://www.bbc.co.uk/info/policies/pdf/dtt_hdtrial.pdf
Interesting report on the BBC's HDTV trials. Not sure of the date of the
report. The trials occurred in June 2006.
<snip>
Some interesting quotes: <<Bert>>
"Trialists expect HD to be delivered on DTT in the near future, though
spectrum restrictions make this unlikely to happen until digital
switchover and only then if further spectrum becomes available for the
platform. ... They also believe that they should be able to receive HD
content for free, ............"
And, <<Bert>>
"Just like here in the US, HD is considered by these realists to be the
new TV standard, not some specialty market for the wealthy few."
<<Snip>>
Yet the vast majority of US viewers if they are HD equipped will watch HDTV via
cable or satellite and willingly pay a subscription fee (except in New Orleans,
unless they can afford it). Brits are specifically interested in nature and
sports programming in HDTV (as most of us are) but in the majority are not keen
to pay for it as a subscription service. There is a big cultural divide among
the less wealthy (everywhere in the majority), between the Brit Freeview +
top-up subscription mentality and the US Payview (what we offer is what you get
and pay for) mentality.
<<Bert>>
Here's a few quotes I just couldn't pass up, for Craig's benefit. These
are initial consumer comments to the quality of HD vs SD and 720p vs
1080i, at normal and reduced bit rates. The 1080i vs 720p tests start at
high bit rate 1080i, then low bit rate 720p, then high bit rate 720p,
then low bit rate 1080i.
Yes, but you neglect other comments made in the report. Example:
"The results (720p and 1080i) at different bit rate were of limited use for two
reasons: (1) The trialist feedback was restricted to 5 days per setting and
did not generate a huge amount of feedback. (2) The low bitrate 1080i pictures
exposed a compatibility issue in a new software upgrade for the encoders and
one of the set top boxes which made it necessary to revert to the old software
before originally planned. This made direct comparison difficult."
(I assume that the software was common to both 720p and 1080i transmissions).
720 higher bit-rate
<<Snip>> (for clarity read the original transcript).
1080 lower bit-rate
"Big improvement this morning with BBCHD reverting to 1080i. The crystal
clarity and naturalness of the picture is back along with that
indefinable wow factor that had disappeared with the downgrading to
720p."
<<Bert>>
Many chuckles on that one. He preferred low bit rate 1080i to high bit
rate 720p.
"Picture sharpness better but much more blocking and noise in complex scenes
and in dark areas. Picture seems a bit strained and not easy to look at at
times."
(There seems to be a disconnect between these two trialists observations).
And, in the conclusions section,
"Each HD channel is likely to need bandwidth equivalent to that required
by three or four standard definition channels even when using more
advanced MPEG-4 technology."
Looks like use of AVC might make reduced bit rate more acceptable, but
to achieve the wow factor required about the same bit rates as used here
with MPEG-2.
Bert
I found it interesting that the report results indicated that the "sweet spot"
for HDTV screen size viewing was 43" or larger. (This is my own and others
opinion as well). I don't think it likely that anyone will broadcast 1080p in
ATSC without scrapping the standard in spite of capable 1080p receivers now
coming on the market. Perhaps 1080p DVDs are just around the corner and may
make use of this screen. (What will the new "sweet spot for screen size morph
into ?)
Finally,
"Analysis in a lab situation revealed significant differences in picture
quality between the settings, but they were not easily noticed in the trialist
homes".
<<my comment>>
I question whether the program source being so varied may have had some bearing
on what the test group experienced. It is also stated that good picture
quality depends on having the fewest number transmission hops from the point of
origination to the broadcast transmitter.
Did anyone watch PGA golf last weekend from the Monterey Peninsula OTA in CBS
1030i ? The broadcast was HD at its best combining stunning views of beach,
ocean and sport in a delicious glitch free color presentation. (Actually my
monitor is 720p and my Samsung STB provided the conversion from 1030i to 720p.
Nick
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