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

  • From: Craig Birkmaier <craig@xxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Fri, 11 May 2007 08:40:09 -0400

At 4:47 PM -0400 5/4/07, Manfredi, Albert E wrote:

But for me, academic exercises have to be truthful to be ethical. With
1080p consumer displays becoming available at really small premiums over
their 720p counterparts, some of the (often way too political) positions
of the past might need to be re-evaluated.

John Shutt wrote:

 > Do we go 720p for production, editing, and storage, assuming we have
 oversampling acquisition cameras? Or are we better off to use 1080i
 throughout the entire production chain, and convert to 720p at the
 emission encoder?

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.

WRONG!

Mark has already challenged you on this. But to go a bit further, you will be far better off using a high quality de-interlacing system, THEN encoding as 720P. It is easy to re-interlace at the display for 1080i displays.


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

Interlaced acquisition did not make sense in 1992 and it does not make sense today. There is no place of interlace in acquisition, production or emission. The ONLY place it still has a useful role is as a way to build cheaper display systems.


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

Almost all existing HD production gear does both since the master clock rte is the same - by intention.

The ability to support 1080i production is not a reasonable justification for its's use.

So to help John with his decision making.

Use only progressive acquisition system and progressive production techniques.

Remember that oversampling is good. So cameras that have 1920 x 1080 sensors (or higher) are desirable. IF shooting high temporal rate material shoot 720P - you will still get the sensor oversampling benefit. If shooting 24P you can master at 1920 x 1080@24P.

In production use flexible tools like Final Cut Pro - the new version can mix any source on the timeline, regardless of the format. You can choose to output at 720@60P or 1080@24P depending on the project.

When producing animations and graphics use 1920 x 1080P - this will give you the benefit of oversampling AND compatibility across projects that are at either 720@60P or 1080@24P.

Output all projects at 720P when you are encoding for emission.

Don;t worry about 1080@60P. Over time you will get some gear that will support it. It will probably be easier to resample to 720@60P for production, although it WILL be possible to edit in 1080@60P then encode at 720P.

Regards
Craig


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