25p footage: what project setting should I use? Help Sony?

PDB wrote on 9/28/2004, 12:51 AM
Hi everyone,

I'm enjoying the wonderful 25p footage from a Pana AGDVX100 (Pal of course...) and the question is should I set the project settings in Vegas to Progressive or leave it as interlaced given that the final format will be a DVD to be viewed on a standard TV. Does it make any difference (in choosing the project settings) if progressive is mixed with interlaced? How will these settings affect render times? (if at all...)

I take it that once done, the render to Mpeg 2 for DVDA is the same irrespective of whether the source is progressive or interlaced, or have I missed an option here aswell?

Just tryin to work out how to get the best out of the progressive footage (which is apllicable to stills aswell...)

Thanks in advance!

Paul.

Comments

farss wrote on 9/28/2004, 2:45 AM
I'm not 100% certain of this so please bear with me.

What you'll have on your tape is 50i, there's still two fields per frame, it just so happens that they were both taken at the same time. Reason for this is there's no other way for the camera to record it to tape.

If you set the project properties to Field Order None (progressive) then all FXs etc will be applied as 25p. You could also leave it as interlaced, your footage will not magically become interlaced, the temporal resolution to do that isn't there. However this may give a slightly different feel to the FXs etc.

Now the comes the bit I'm a bit uncertain of. The DVD spec doesn't support 25p as far as I know and I doubt there's any DVD players / TVs that do either. You can easily convert from 25p to 24p (One of the Sony white papers covers this). However as I understand it 24p is only supported at NTSC frame size which means (I think) you're going to loose out there.

I'm hoping one of the Sony guys can clear this up, I've never fully understood this. I do know that 24p DVDs will play in both PAL and NTSC systems which makes them mighty handy.

Bob.
PDB wrote on 9/28/2004, 3:02 AM
Bob,

Thanks for those first pointers...You are right of course that the camera lays the video on tape as 50i...I wonder if the settings do however affect how the actual frame is treated on the timeline: ie having a complete frame 25x per second as opposed to having the frame made up of two fields (if that makes a difference at all....I'm not sure I understand the differences enough to be able to make a educated decision as to what's best...) I'm also curious as to what difference it will make when applying effects (in my case its usually curves and/or colour correction...)

I follow you on the dvd specs thingy aswell...I read the paper on 24p and soaked a whole load of info from different boards...I wish there was a very simple explanation about 25p somewhere: I mean, just a couple of pointers as to the best settings for timelines and dvd to get the most of the progressive footage, even if it is a "dont worry, just use the PAL interlaced template and normal dvd settings and you will get the most out of it anyway"...
And these issues are true for Photo montages, given that all source material is progressive (including any media generators/text from Vegas)...

Anyway, I might actually invest a bit of time and try different options to see if there is a discernible difference.

Thanks again!

Paul.

PS edit: just thinking about the 24p dvd idea...I see what you mean that if it is NTSC resolution, we lose coming from Pal. But what would happen if we make that a 24p 16:9 dvd coming from a Pal 4:3 footage and letterboxing? Am I right to assume we do have much greater flexibility in terms of framing(panning)/zooming since there is higher resolution than what is seen on screen? Would that be a possible advantage? Just trying to see the possible positive factors which could play to our advantage in PAL land...

Thanks again!
farss wrote on 9/28/2004, 5:34 AM
Paul.
The difference that the project settings will make should only affect temporal transistions i.e. page curls. I cannot see how it would make a visual difference to CC, don't know about a dissolve though, interesting thought.
The only reason I know about this is it did come up in discussion about how a lot of US shows are shot. Shot on 35mm but edited as video in 60i I'm told this gives a kind of unique feel that's different to editing at 24p and then applying pulldown to give 60i

Where you'd most likely see the difference is using panning on generated media. Shooting at 25p you should get quite a bit of motion blur but if the project is 50i then the generated media will have less motion blur so to get it to match you'd need to apply MB or even use Supersampling to simulate the effect of a possibly slow shutter speed in the camera.

Cropping the PAL frame to fit the NTSC frame does ltlle for real resolution. The bit that I don't get (HELLO SONY!) is this:

OK, my DVD player can play out 24p to my PAL TV. But I assume my PALTV gets fed 625 lines but the NSTC frame is only 525 lines? What happens? Am I forced to downres my PAL footage to 525 lines so I can render a 24 p mpeg-2 stream for the DVD only to have the play up the res back to 625? Wish I knew more about this.

Bob.
PDB wrote on 9/28/2004, 6:59 AM
Yes I see what you mean now about the 24p on a Pal system...I would assume in terms of framerate compliance the dvd player would just increase the playback rate and interlace to match the PAL specs...(may well be wrong of course). No clue as to what happens in terms of resolution...
I guess the question really in my case is whether there is any point in doing the 24p conversion (I think not) and again what is the recomended process and caveats for 25p depending on source media and final delivery etc...perhaps a 25p white"paper", or say just a litlle paragraph? Actually on second thoughts, the 25p question is applicable to footage taken at 30p (30p timeline or 60i). So what do people do with 30p footage? Or am i just being really dense...??

In effect, so far I have stuck to a standard PAL Dv template (lower field first) to work on this footage and it does work. I will give the progressive template a go and see what happens, especially with things like dissolves (which I do use frequently).

Thanks again Bob,

Paul.

Ps I added a plea of help to Sony in the hope we can grab their attention....
SonyEPM wrote on 9/28/2004, 7:27 AM
Assuming you are authoring PAL DVDs and your source material is 25p:

For PAL DVD content creation, you should use the Vegas PAL DV project preset with one change: the field order should be set to progressive. Save as new preset "PAL DV Progressive" for easy recall.

Rendering MPEG-2: Use the PAL DVD presest, again changing field order to progressive. Save as new preset "PAL DVD Progressive" for easy recall.

In DVDA: Use the PAL preset, no changes. Your PAL DVD Progressive MPEG-2 files generated in Vegas will not have the video recompressed (which is what you want).

If your footage is 16:9 change to "widescreen" in all 3 steps above.


PDB wrote on 9/28/2004, 10:53 AM
Well that's very interesting! I take it dvd players do play back 25p mepgs?

Must give this a go...hopefully tonight!

Thanks again SonyEPM....

Paul.
SonyEPM wrote on 9/28/2004, 11:32 AM
Are you authoring PAL DVDs for PAL DVD players?
PDB wrote on 9/28/2004, 12:37 PM
Yes SonyEPM...The final medium will be PAL DVD to be played back on regular set-top Pal dvd players ...
farss wrote on 9/28/2004, 3:19 PM
I'm guessing this should work, from my little knowledge the mpeg-2 encoding works at the frame level anyway. The playout converts to interlaced for the TVs benefit.
Still curious to know about the 24p conversion though, is 24p only at NTSC res?

Bob.
fabio wrote on 1/7/2005, 5:15 AM
Does Movie Studio 4.0 handles 25p too????


Or the entry level program does not support it...


THanks

FAbio