1080PsF on HDDVD & Blu-Ray disk to playback 29.97fps

[Robert McGee]

According to this chart from wikipedia.com, only 24fps video on an HDDVD and Blu-Ray is the only video capable of being played back at Full HD 1080p

http://en.wikipedia.org/wiki/Compari...l_disc_formats

For 1080i if it is PsF formatted, how do you think the picture would look if played back on either a 1080p, 1080i, or 720p set?

http://en.wikipedia.org/wiki/Progres...egmented_Frame

[Michael Jouravlev]

My understanding is that PsF is strictly 24fps. Therefore it cannot be directly played by consumer equipment. So it will... er... not look at all :) It seems to me that 30p in the form of 2:2 60i video, as well as 25p in the form of 2:2 50i video, cannot be called PsF simply by definition of the PsF, which is supposed to be 24fps (see Charles Poynton's book "Digital Video and HDTV: Algorithms and Interfaces", p. 62)

[David Heath]

Originally Posted by Michael Jouravlev

My understanding is that PsF is strictly 24fps.

I don't believe that's true, and 1080psf/25 is what most HD broadcasts in Europe currently are - at least for drama etc. As for how it's displayed, I believe it depends on the display. Cheaper ones may just treat it as simple interlace (which is effectively what the underlying signal is) whilst more sophisticated receivers should recognise the difference between i and psf and deal with it accordingly, hopefully reconstituting the original true progressive signal.

Which is the beauty of psf - compatability with interlace systems, whilst maintaining a true progressive signal.

[Greg Boston]

Originally Posted by David Heath

Which is the beauty of psf - compatability with interlace systems, whilst maintaining a true progressive signal.

That is its purpose. To carry progressive images in the same signal chain used for interlace formats.

-gb-

[Michael Jouravlev]

Originally Posted by David Heath

I don't believe that's true, and 1080psf/25 is what most HD broadcasts in Europe currently are - at least for drama etc.

Yup, I know that 2:2 pulldown is the same thing as a segmented frame, I simply was not sure whether the term "segmented frame" assumed specific frame rate as well as specific usage. The section in Poynton's book is entitled: "Segmented Frame (24PsF)", but what does American engineer know about PAL? ;) Interestingly, he is not fond of this scheme: "Proponents of the scheme claim compatibility with interlaced processing and recording equipment, a dubious objective in my view." I don't think he objects using segmented frame for distribution purposes, but rather using it for acquisition and mastering. This just made me thinking that "PsF" is a term used for production, while "2:2 pulldown" is a term used for broadcast.

I agree that the display should either read the flags or detect the cadence, but without proper progressive/pulldown flags, the process of identifying 25p in 50i video seems to be a harder task than identifying 24p in 60i video.

[Robert McGee]

The question is really for more about HD video that is shot at 30 frames,

say like a sporting event like a football game, if the NFL wanted to distribute old games on HDDVD and Blu-Ray because when I look at them, I know that the game is being shot in HD but it also being semilcasted in SD for people who only have SD and EDtv's, the games in particular look like their being shot at 30 frames because HD cameras that could capture actual 24fps feature film standerd didn't come out until 2000 and the NFL has been shooting and broadcasting games in HD since 1998.

[Michael Jouravlev]

Sports is not shot at 24p. Either 60/50p or 60/50i.

[David Heath]

Originally Posted by Michael Jouravlev

Interestingly, he is not fond of this scheme: "Proponents of the scheme claim compatibility with interlaced processing and recording equipment, a dubious objective in my view." I don't think he objects using segmented frame for distribution purposes, but rather using it for acquisition and mastering.

In a purist sense, he may be right. In a pragmatic sense, psf enables existing (interlace) equipment to be used to view, record etc the signal whilst maintaining the ability to exactly reconstitute the original true progressive signal for editing, and that's true of 24, 25 and 30psf variants. (The former needing 3:2 pull down.)

I agree that the display should either read the flags or detect the cadence, but without proper progressive/pulldown flags, the process of identifying 25p in 50i video seems to be a harder task than identifying 24p in 60i video.

I would hope the stream carries a psf flag, in the same way current SD digital broadcasts carry a 4:3/16:9 flag. Whether the display can make use of it, or just treats everything as interlace, is another thing again.....