NTSC DVD doesn't support 30p. But that's OK, because converting it to 60i is easy as weezy. It'll look just like 30p when played.

Yeah but will it uprez on an upconverting DVD player or HDTV with an upconvertor or one of the new Toshiba HD-DVD players or the current Samsung BlueRay player?

I don't see why not, depending on the specifics of the player.

The reason it wouldn't would be because it would think the 30p was 60i and apply a blend fields or interpolate deinterlace, reducing the resolution, and not even try to uprez. It certainly is possible to uprez 30p, but it is an uncommon format and I suspect that manufactures don't have to demand to accomodate it. I don't know for sure though. Somebody must. Usually there are all kinds of experts around here.

OK, the closest thing I can find to an answer about how different DVD players handle 30p video is here:

http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html

Going down a ways, there is specific discussion of 30p and 2-2 pulldown. Going further into the article gives more information including how specific players hand deinterlacing with both 3-2 and 2-2 pulldown. It seems that some players handle 30p quite well while others fail miserably. Anyway, after quite a bit of searching, that link has the best information I've found so far.

On this page, you can look up how well a given DVD player handles different types of material, including 2-2 pulldown removal. There is reference there to 2-2 pulldown flags. Is it possible to set a 2-2 pulldown flag with Vegas and DVD Architect? Does taking the default 60i Widescreen DVD Architect template and changing the video mode tab from interlaced to progressive set the 2-2 pulldown flag that some DVD players will recognize?

http://www.hometheaterhifi.com/cgi-bin/shootout.cgi

Well I've started running tests and have answered at least one of my questions:

No I cannont set a 30p 2-2 pulldown flag with Vegas and burn it to DVD with DVD Architect. If I try DVD Architect wants to re-render the 30p mpeg as 60i. Is there another DVD authoring program that will let me do this?

Also, I suspect that Vegas 7 / DVD Architect 4 is just around the corner. This would be a welcomed fix: being able to set a 30p 2-2 pulldown flag with appropriate templates to take out the guesswork.

OK a little more research and I found the following: that some DVD players (usually high end ones with line doublers) get confused by 30p DVDs with the progressive flag set. What happens is that when these DVD players see a progessive scan flag, they automatically assume that the footage is 24p and start using a 3-2 pulldown removal which of course looks terrible on 30p 2-2 pulldown footage. As a result, it is extremely likely that DVD Architect will not allow 30p with a progressive scan flag because it is better to avoid this situation entirely by just letting the DVD player think the footage is interlaced.

If the DVD player blended fields, it would put together two fields which comprise a whole 30p frame. There would be no resolution loss. At least there would be no FURTHER resolution loss; when you've converted 60i to 30p, you've already lost resolution (leaving aside the downrez to DVD from HD).

But you're talking about something other than uprezzing to HD here:


"OK a little more research and I found the following: that some DVD players (usually high end ones with line doublers) get confused by 30p DVDs with the progressive flag set. What happens is that when these DVD players see a progessive scan flag, they automatically assume that the footage is 24p and start using a 3-2 pulldown removal which of course looks terrible on 30p 2-2 pulldown footage. As a result, it is extremely likely that DVD Architect will not allow 30p with a progressive scan flag because it is better to avoid this situation entirely by just letting the DVD player think the footage is interlaced."

That's what I said before -- DVD does not support 30p. Only 24p and 60i. And watching 30p in a 60i stream will still look like 30p, just like watching 24p with pulldown still looks like 24p.

In any case, you can't set DVD Architect with "progressive flags" with 60i or 30p material. You can make a 24p DVD, which will require a 24p file (either rendered from Vegas, or DVDA will do it when it authors), or you can make a 60i DVD.

If you were to drop a 30p file in a 24p DVDA project, and DVDA converted the file to 24p, it would look terrible, because 30p does not convert to 24p well at all. But that doesn't have anything to do with "progressive flags"; it has everything to do with there not being enough temporal imformation in 30p footage to make a good conversion to 24p.

Well the deinterlace step happens before the uprez step. If you lose resolution on the deinterlace, that negatively effects the uprez. If you have a 30p piece that is flagged as 60i and the DVD player doesn't uprez 60i, that is going to effect whether or not an attempt at uprezzing is even made.

If you're creating a 30p file, then you have to deinterlace before you go to DVD, so you've lost resolution before you ever get out of Vegas. Then, on DVD, it will be encoded as 60i, splitting each 30p frame into two 60i fields. There's no way around this; there are no "flags"; it's just a 60i file.

When (if) the DVD player deinterlaces, if it blends fields, it will put the 30p frames back together.

But like I said, it depends on the specifics of what the player does to uprez. If it does uprez 60i, then you're fine. If it doesn't, then you're not. But in either case, it doesn't matter if you converted your 60i footage to 30p or not; you're still bound by the rules of 60i in terms of how the player handles it.

Well if you start from a1080i video, you have plenty of resolution to give you full 720x480 at 60i, 30p or 24p. I can go to any of these formats at SD resolution without compromising resolution at all. That is the point of doing it this way instead of just letting the player handle it.

I've been running all kinds of tests and have found the following:

1/ If I render a 30p DVD and play it from WinDVD or PowerDVD, I get an image that has noticably better vertical resolution. Diagonal lines like roof edges don't noticably staircase like they do at 60i.

2/ This is not the case on my CRT TV (which has a compress mode for true widescreen). On that TV, both versions look equally sharp, but the 60i version is smoother.

3/ 24p is something I'm going to give up on until I want to make a commitment into dolly tracks, solid tripods with fluid heads, and some sort of a steadycam. Otherwise the lack of temporal fluidity just drives me nuts.

This leads me to believe that 60i looks better on TVs that can handle 60i, but that 30p would be noticably sharper on any playback device doing 30p like computers or the current crop of 1280x720 LCD and lower budget plasma TVs.