[opendtv] Re: News: See the Big Picture? Don't Forget to Examine the Fine Print
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 3 May 2004 12:00:42 -0400
Craig Birkmaier wrote:
> >I think I said world wide standard for DTV. Those PBS nature shows
> >the article was talking about are transmitted in what aspect
> >ratio, Craig? Care to guess?
>
> 4:3 on the NTSC channels
> 16:9 on the DTV channels
> 14:9 on BBC channels in the UK.
Ooops. Guess again. Perhaps the BBC uses 14:9 for widescreen to
analog channels, and it distributes 14:9 to mostly non-digital
*export* markets, but 14:9 is nbot the BBC standard for DTV.
See =
http://www.bbc.co.uk/guidelines/delivering_quality/pdf/tv_standards_londo=
n1_5.pdf
(This porobably got corrupted, but you can find it at the BBC
web site.)
Here's the specific quote:
------------------------------
4.1.5 Aspect Ratio.
Programmes will be commissioned either for 16:9 Widescreen or 4:3
Standard presentation. 16:9 Widescreen presentation is also known
as "16:9 Full Height Anamorphic" (FHA). Letterbox delivery of 16:9
programmes is not acceptable.
Format changes within the programme to maintain the 16:9
presentation should not be required. Active picture width is
52us / 702 pixels. All aspect ratio calculations are based on this.
Any processes based on 720 pixel width may introduce unwanted
geometry or safe area errors.
4.1.6 Safe Areas for Action and Captions
Captions and action shall be within the safe areas specified for
delivery. There are four standard safe areas defined for UK
transmission which are generally applied depending on the aspect
ratio and type of programming. Currently (April 2002) it is
Television's policy to commission programmes in 16:9 (protected
for 14:9), except for Sport which is 16:9 Widescreen protected for
4:3 centre cut-out, and feature films which are in unprotected
16:9 Widescreen. In addition, certain types of programming such as
Promotions, BBC Worldwide and BBC Sport frequently require full
4:3 protection - the details of which are shown in the table below
as e.
In Transmission Review (see 6.1.1) programmes are assumed to be
Widescreen and 14:9 Protected unless otherwise specified.
Note: For widescreen programmes protected for 14:9, captions taken
to the very edge of 14:9 caption safe are likely to be clipped
when viewed on a poorly set-up domestic 4:3 receiver/Set Top Box
combination. For this reason, 14:9 caption safe is best regarded
as the maximum allowable width. Productions preparing for Worldwide
delivery should refer to the separate BBC Worldwide standards
document, as 14:9 is currently a UK-only protection standard.
A table of typical requirements is given below. Detailed diagrams
of the UK TX standards are in the Appendix, section 7.
-------------------------------
Bert
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