Re: [libdv-dev] 24fps and true 16:9 DV samples

[Steven M. S. <sm...@2B...>]

On Tue, 2 Nov 2004 da...@de... wrote:

> I have some samples of different 16:9 modes that were shared here
> previously. I can make them available tonight. What do you mean by true
> 16:9? As far as I know, there is only anamorphic (aka squeeze) and
> letterboxed.

	Camcorders usually have a 4:3 CCD and either use a letterboxed
	area of the CCD (basically the middle 360 pixels out of 480) _or_
	an anamorphic lens adaptor.

	I have read about new camcorders that have a 16:9 CCD and use a
	~960 area of the CCD and do not  letterbox or require an anamorphic
	lens.   960 10:11 pixels works out to around 854 square pixels - the
	rest of the arithmetic is left as an exercise for the reader :)

	Couple good examples of non-letterboxed 16:9 CCD camcorders are
	the Canon XL2 and the Panasonic AG-DVC200.

	What's puzzling is what happens next.  If a 16:9 CCD is used without
	an anamorphic lens then is the ~960x480 frame put on tape or does
	the camcorder scale/resample to anamorphic form?

> Also, for some reason - perhaps based on past casual reading at
> digitalmedianet.com - I believe that the 24fps DV is progressive scan with
> a 2:3 pulldown applied to make it run at normal rates for compatibility

	Yes, that's what I have read also.

	Panasonic (and perhaps others) also offer a "24P Advanced" mode
	which uses a 2:3:3:2 pulldown rather than a strict 2:3 pattern.

http://catalog2.panasonic.com/webapp/wcs/stores/servlet/ModelDetail?storeId=11201&catalogId=13051&itemId=68668&catGroupId=14571&displayTab=R&surfModel=AG-DVX100A&surfCategory=DV%20PROLINE%20Camcorders

	sorry it's so long but it might be of interest.

> with existing DV tech. Hopefully, there is some flag in the stream. What
> information do you already have about this?

	The only info I have is from the various vendor's sites (Canon, 
	Panasonic, and so on) and Apple's Final Cut Pro-HD (which claims to
	deal with everything up to HD) documentation.


	Cheers,
	Steven Schultz