720/50p vs 720/25p (60p/30p resp.)

alpi69

alpi69

Veteran
Theory lesson needed!

I am in PAL so use 50p and 25p but it is the same for 60p/30p.

My question is this: What is the difference really between 720/50p and 720/25p?
In 1080 there is only 50i or 25p like it was in PAL, right? But in the 720 resolution there are two standards. And I read somewhere the broadcast will eventually be in 720/50p. I understand the 50p is in 50 frames per second and 25p is 25 fps, but why make these two standards if the whole system so far was based on 25 frames. Why do they introduce a 50p standard? It will only cause headaches for all footage in 25p/50i.

So this leads me to a dilemma. Right now I ask why should I at all use anything else than 25pN. It saves storage on the P2 and it allows me to quickly use variable framerates. Why use 720/25p or 720/50p. That will use more bandwidth/space.
But if the broadcast would be in 720/50p my footage would be wrong speeds.
I am totally lost here. I make 25p timelines and drag 25pN footage in and all is as it should be. But what if I get asked to deliver a 50p timeline. What happens to my footage in the end? Am I paranoid or is there really something to take care about?

I found this thread: http://www.dvxuser.com/V6/showthread.php?t=72210&highlight=720/50p
but I am still not sure what this means for the Broadcasting and Outputting to some sort of DVD. Ok, 720/50p makes 50 frames a second and in a timeline in that format would be normal speed because it is replayed at 50 frames per second. Now that sucks once I want to add slomos, because suddenly my HVX can only play normal or undercranked. When Barry says "it looks great shot in 50 fps and played back in 50fps i understand that, but how does CBS broadcast the NFL games then? How do they get slomos in? Do they have cams that shoot 100 fps suddenly?

I found this article and it is a MUST READ for all of us!! http://www.ebu.ch/en/technical/trev/trev_299-ive.pdf
Still I would like to know how you guys PRACTICALLy solve this when planning for a broadcast: shoot 1080/50p and then use 720/50p for over-undercrank and then use post to actually get these cranks done?
 
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As far as I know:

YES, 50p will be the european standard for many TV-stations - so it will be for Switzerland for example.

Now - modern TV-sets display progressive, so this is why the standard aims to broadcast progressively too....

But... 25p is stuttering.... so the TV-stations are going to double the frames for TV-shows, documentaries etc. to obtain (false) 50p footage.

Our advantage will be, that we can deliver 50p footage to european TV-stations with 50p standard.... (in future...).

Probably movies will be broadcast in 25p (so are they also on Blu-ray Discs). This will result in a cinematic stuttering that will be accepted by the audience.

This is the Link to the EBU format comparision (made at IBC Sept. 2006) that leads to the new standard: Future HD-format in Europe

The responsible institutions in Europe for HD-standard setting are EBU and ITU. If you google them, you'll find all informations needed about the coming standard.

further Link (in German, valid for Europe...):

General HD-Standard Info
 
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That report from IBC is very interesting. Especially this:
"The 720p/50 format showed better image quality than the 1080i/25 format for all sequences and for all bitrates;"
If you read how careful they tried to get this as a fair comparison of the formats it is amazing that the screen showed 720/50 better than 1080/25.

And this line hits the nail:
"We can clearly recommend the use of 720p/50 as a television production format today."
 
alpi69 said:
And this line hits the nail:
"We can clearly recommend the use of 720p/50 as a television production format today."
Click to expand...

And this is what the HVX offers natively! - Lucky us!! - :)
 
There is a huge gap in the EBU argument as linked to above, namely 1080p/25 (1080p/24 in 60Hz countries). Is it a huge gap? Since most non-sport HD broadcast production - drama etc - is currently produced in such a way, and intended to be transmitted 1080psf/25, then the answer must be yes. And with blue laser disc Hollywood films also seeming to standardise on 1080p/24, the EBU not mentioning such seems rather odd.
alpi69 said:
Theory lesson needed!.......
My question is this: What is the difference really between 720/50p and 720/25p?
Click to expand...
In two words: motion rendition.

50p gives smooth motion, and is generally seen as better for sport, live action etc, whilst 25p gives the "jerkiness" which often helps characterise "film look".

And that's the problem with the EBU argument. They assume that HD=smooth motion, and must therefore be either 50p or 25i. They completely ignore the mass of drama production, and all feature films, which are 24 or 25p, often by preference!

IF their assumption (nothing but 50Hz motion) was valid, their argument makes a lot of sense, the only counter may be that an eventual move to 1080p/50 may then be less likely as an end game. But since for most channels, 24(25)Hz motion content is likely to be extremely important, then that must mean 720p/25 in their eyes. With "FullHD" panels starting to now become commonplace, that means that broadcast material will look soft in comparison to blue laser discs.

The contest is not simply 720p/50 v 1080i/25 as they claim, but 720p/50(p/25) v 1080i/25(psf/25).
 
by the way: IMHO the two last EBU papers (Links) that date both from 2004 are much too old. That time, the european HD-station was called "Euro1080" and was about to set a new standard for broadcast for itself... Today, the name changed into HD1- HD5 and its broadcast is about to change the (at least) third time. So actuality seems to be very important in the definition of "broadcast standard".

Just my 32 cents (VAT excl.)
 
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