eerste antwoord van de EBU !
zie hier het eerste antwoord van de EBU, gevolgd door mijn antwoord. Ik ga ervan uit dat inmiddels onze discussie op vele plaatsen gevolgd wordt, en dat we dus op zijn minst enige impact hebben op de technici. Laten we dan ook fatsoenlijk blijven in hoe we onze kritiek uiten!
Dear Mr. Van Horck,
Your e-mail has been forwarded to me, in order to provide with some answers
First of all let me outline the configuration for the ESC and one correction
to a misunderstanding on your side.
The material is produced in 1080 INTERLACED with 25 frames (or 50 fields).
There is NO 1080p ESC.
Display which use the slogan "Full HD" are characterized by 1920x1080 pixel
resolution. Full HD does not describe the broadcast signal - even if many
people wrongly do so.
We have conducted a number of scientific test with about 300 non expert test
persons and found that a well done 720p/50 signal when displayed on a Full
HD display with 50 inch diagonal at 3h viewing distance does NOT lead to
We also found that a full progressive chain with 720p/50 from camera to the
consumer provides a solid and high quality HD for the next years until
1080p750 production becomes feasible (i.e. 2012-2015). In addition there is
huge benefit in bandwidth saving since a progressive signal can be better
compressed in distribution/emission to the consumer.
However: broadcasters which distribute their signal in 720p/50, but use a
1080 INTERLACED source signal (like the ESC) need to apply standards
conversion 1080i/25->720p/50. There are huge differences in the product
quality of standards converter and this (plus the broadcast encoder and
available bitrate) determines whether the quality at the consumer premises
is good HD or less good HD. As a rule of thumb we can say that professional
motion compensated standards converter plus a very good broadcast encoder
requires about 13 Mbit/s Video bitrate for good HDTV to the home.
Our recommendation is very clear that the future of HDTV broadcasting is p50
and the EBU will not recommend to use interlaced HDTV.
I hope that these explanations give you some assistance. Please do not
hesitate to contact me with further questions.
Dr Hans Hoffmann
Senior Engineer EBU TECHNICAL
Dear Dr Hoffmann,
Thank you for your comprehensive answer! This is very much appreciated!
The questions arose on our forum as the viewers in Holland were in some case able to see both the Dutch HD Broadcasting Ned 1 in 720p as well as the BBC HD broadcast of the same Euro 2008 game which was transmitted in 1080i over satellite.
The perception was that the BBC picture quality was significantly better, leading to the hypothesis that as the stream was 1080i perhaps in this specific case of a interlaced stream it would be better not to try to convert back to a progressive picture.
Are you at all able to comment on this hypothesis?
I should add that the forum readers totally agree without that progressive scan must be the future and interlaced is not. I guess however we had hoped that the transition to 1080p would have gone quicker.....
I should add that over the last few games i seem to have noticed that the directors of the recordings have started reducing the panning over the field in wide angle, leading to less quality loss in the detail on the grass. So HD brings changes there too...
Thank you again for your time!
In the meantime though, kind regards from Holland (Orange country as you may have noticed)