1080i25? is it 25i or 50i or 25p

[Michael Gissing]

My understanding is that HDCam shoots 50i. When shooting a progressive image it shoots in 25psf, which means progressive segmented frame and that signal is 50i.

All the HDcam work that I have done has been captured and edited in a 50i sequence, regardless of whether it was shot 50i or 25psf. That said, I only deliver to broadcasters who spec 1080 50i. If you are scanning back to film then progressive sequences may be needed. Never heard of 25i. I suspect it is actually 50i.

[Carsten Orlt]

Its annoying, isn’t it!!

The same thing called different names.

There is no 1080p for broadcast! All 1080 broadcast footage is interlaced = i

On tape it is always 1080i50 for PAL.

What Aja calls 1080i25 should be better called 1080psf25. (progressive segmented frame)

What you did before you got confused was the right thing for progressive shot footage.

Carsten

[Gary Adcock]

[Carsten Orlt] “There is no 1080p for broadcast! All 1080 broadcast footage is interlaced = i “

Very True – but not all content is captured for broadcast – Maybe it would be better to ban the hype and call it what it is- but remember that there is a difference between 25i (every field has a dupe) and 50i (where every field is different)

25 is no different than 29.97 – it tells the number of frames not the number of fields.

“On tape it is always 1080i50 for PAL. “

That is really not possible since PAL is only a standard def format – it is not an existing HD format sorry. Not to mention that the BBC also lists specs for 25psf deliverables not just 108050i and the EU does support the 720p50 format also.

In HD the only thing different is the frame rate – there is no longer any difference in the color space between the 25/50 worlds and the NTSC of the US and Japan.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD

[Tulio Campregher]

BBC calls it 1080i25, as it is 25 frames per second, no-one calls NTSC as 60i or PAL 50i, and some cameras can actually shoot at 50p, what would they call it?. so it makes sense.

Tulio

[Tom Wolsky]

They call it 1080p50 or 1080p60.

All the best,

Tom

Class on Demand DVDs “Complete Training for FCP6,” “Basic Training for FCS2” and “Final Cut Express Made Easy”
Author: “Final Cut Pro 5 Editing Essentials” and “Final Cut Express 3.5 HD Editing Workshop”

[Gary Adcock]

[Tom Wolsky] “They call it 1080p50 or 1080p60.”

they call it 1080i25 for capture and 1080 50i for playback.

Sony calls it ‘P’ (erroneously) – Sony’s format is PsF-it is captured as progressive – however plays back as interlace to be more compatible with existing systems.

Since only 3 sony camera models can actually record at 1080 50p or 60p (and notice that is a “p” and not “PsF” ) which are actually being used for Slo-Mo like the varicam does – just in the larger 1080 frame geometry, however 50p /60p work in 1080 requires a Dual Link capture setup and an array fast enough to sustain the over 400 MBps needed to capture.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD

[Luke Hardiman]

So just to get back to basics for a second,

if the cameraman shot at 1080 25p, but FCP imports it off P2 as 1080 50i, I just need to set the field preference to “none”, and I will be working at and delivering 1080 25p

Thanks

Luke

[Jay Moffat]

I have been asked recently, but could not give a definitive answer: Is there a quality loss rendering 50i footage out from FCP as 25p, and is that actually what should be supplied as a digital master?

I’ve tried a couple of tests but not been able to see a discernible difference, if any…The footage I was working with was shot progressive but presumably enclosed in a 50i wrapper..

J

[Rafael Amador]

Hi Jay,
If the footage have been shot progressive, should be checked a NONE in FC, even if have been captured as Interlaced (Psf). Then can be edited in any Progressive or Interlaced sequence without problem.
If the footage is Interlaced, the only way to make it work in a progressive sequence is de-interlacing it.
If you are not sure if the footage is Progressive or Interlaced, you can use AE. Step field by field; if you see no difference every two field, then is Progressive.
rafael

http://www.nagavideo.com

[Jay Moffat]

Hi, it’s not whether it’s interlaced or not, I was wondering if there is a quality loss of what we call progressive shooting, where there are two identical frames in 50i, then rendered out to 25p..?

J