[opendtv] Re: Some results - 1080p @ 60 is Next?

  • From: "John Shutt" <shuttj@xxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Fri, 4 May 2007 17:26:16 -0400

Oops, in cutting and pasting I missed the following:


----- Original Message ----- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>

To remain within the existing ATSC transmission standards, my take is
that:

1. If your acquisition is 1080p or 720p, you should use 720p
transmission.

2. If your acquisition is 1080i, then you should use 1080i transmission.

3. And furthermore, going to 1080i or 1080p acquisition is the right
decision for the future. Preferably, of course, 1080p.

Your conclusions are the opposite of the EBU findings, keeping in mind that theirs was a demonstration, not an exhaustive study. The EBU conclusion reads:

------------------
From the considerations given in this Appendix we can conclude the following:

* The spectral distribution of a 720p/50 and an 1080i/25 signal is basically similar in spatiotemporal
volume;

* The 720p/50 signal should provide better movement portrayal and the 1080i/25 system should provide more detail via the higher horizontal resolution;

* Kell and interlaced factor both "reduce" the available resolution while the interlaced factor reduces the vertical resolution of the 1080i/25 signal. Considering all factors, a 720p/50 signal seems to have more advantages than a 1080i/25 signal;

* A concatenation of different HDTV formats and operating with horizontal sub-sampling should be avoided.
------------------


Not being a broadcaster, I do not understand intuitively why production
facilities can't be adjustable to 1080i or 720p.

Because most HD broadcast equipment is designed to be switchable between 1808i and 720p, but does not do so "on the fly." You cannot edit 1080i and 720p scenes together. You have to convert one or the other to a common format, and every conversion introduces errors and cross converters are not cheap. You must operate in one format only, so it is best to optimize all of your chain for that format.

John




----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:

- Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word 
unsubscribe in the subject line.

Other related posts: