Native 24P vs Post 24P

[James McCrory]

My understanding is that the V1 is capturing more image data when recording in interlaced mode; "over-sampling". And that progressive footage is carried in a 60i stream, and data discarded when pulldown is removed, wasting precious bandwidth. Since software in post can take it's time to render as opposed to having to process the image data instantaneously in-camera, (plus having a variety of software to choose from) could better 24P results be obtained by shooting interlaced and converting the footage in post?

I asked this question to Mike Curtis at 'HDforIndies' and he flatly said "no, shoot progressively or your motion will look all screwy." Rather than take his word as gospel, I would prefer to hear some opinions from people who have shot with the V1, or have used other non-progressive cameras and converted their footage in post.

Although I am the proud new owner of a V1U, I am not currently in a position to conduct all of the necessary tests to see for myself. I want to begin shooting for a new project. For the sake of keeping my options open, and having more control later, would it be perfectly reasonable to begin shooting interlaced? Or will I be sorry later?

[David Tamés]

The rule of thumb is, if you want a progressive video result, shoot real progressive to start with if you can. Going through conversion later will only be a pain and add delays to your post schedule. Mike Curtis is right. Listen to him. To ignore good advice is folly.

[Steve Mullen]

Originally Posted by David Tames

The rule of thumb is, if you want a progressive video result, shoot real progressive to start with if you can. Going through conversion later will only be a pain and add delays to your post schedule. Mike Curtis is right. Listen to him. To ignore good advice is folly.

He's only half right. Shoot progressive if you want it. But, unless edit with Vegas DO NOT shoot 24p! Shoot 25p or 30p. There is no wasted bandwidth.

Progressive at 24, 25, and 30 screws-up motion. If you care about smooth motion -- shoot 50i, 60i, and even better, 50p and 60p. I suspect he may have been talking about 50p and 60p. Else he 100% wrong.

PS: I have no idea where the "double sampled" idea came from.

[David Tamés]

Originally Posted by Steve Mullen

Progressive at 24, 25, and 30 screws-up motion [...]

I guess "screws-up" is a relative term. 100 years of 24 fps film capture (essentially progressive) has never been considered "screwed up" but just the way it is, the strobing that is observed with certain movements is part and parcel with the film look, and is easily mitigated (e.g. track with a moving object and the perception of strobing goes away). It's interesting that over the years filmmakers adapted to working in 24p in such a way that most of the time camera work would hide the strobing most of the time in the way the camera movement was chooses and how it followed objects, and at other times we've chosen to exaggerate it with increased shutter speeds and certain camera movements.

Originally Posted by Steve Mullen

[...] If you care about smooth motion -- shoot 50i, 60i, and even better, 50p and 60p. I suspect he may have been talking about 50p and 60p. [...]

No doubt that motion is smoother at 60i vs. 24p or 30p, but smoother motion in isolation is not necessarily the only thing you want to optimize for. The cost of smoother motion through the use of interlace is less actual resolution (compared to progressive) and interlace artifacts (i.e. jaggies on edges in motion). But yes, the price of progressive at lower frame rates is typically seen in the form strobing artifacts. And the higher image refresh rate (60 fields per second vs. 24 or 30 frames per second) makes the image look more real, rather than "filmic" (perceptually) which is not always a desirable thing. Sports looks better in 60i, but stories work better at 24p or 30p. It's not bad advice to shoot progressive if it's what you want in the end. 60p is a unique look in and of itself, feels more real than 24p or 30p. Too real in some cases, just right in others.

The complicated aspect of this question, is why one wants progressive in the first place? Is it for perceptual reasons? I do digress a bit but not really, the technical decisions we make have all sorts of aesthetic ramifications.

[James McCrory]

My understanding is that there are two rationales for shooting 24P. One is you need to have your project at 24fps if you want to go to film out. Which is something I'm not sure I really need to do. The other is an aesthetic preference for the motion of 24fps. To my eye however, the motion that the V1 produces when shooting 24P appears to strobe more than the motion we are used to from the cinema. And I don't want to create a project whose motion people find distracting and possibly irritating.

My thinking was it might be better to shoot in the format that captures the most image data and smoothest motion in order to keep my options more open and flexible in post. Because I know that it is possible to convert 60i footage to 24P if it should be necessary, but if I shoot everything in 24P my footage will all have that strobing motion and that will be that.

Since there are so many new venues for getting your content to the public these days, I wanted to do things in a way that would give me the most options later. So really my question was, is this a perfectly sound approach or are there other factors and things I need to consider?

[James McCrory]

After conducting some shooting tests last night I realize that the default (and often recommended) shutter speed setting of 1/48 was responsible for the motion that I found disagreeable when shooting in 24P mode. By changing it to 1/24 the motion becomes smoother, more natural looking. I am now reconsidering the possibility of shooting at 24P as has been recommended.

Should I decide to go that route, what would be a good workflow for a Mac user like myself. I have not yet upgraded my computer station so I am open to any editing software, codec, or capture device. I have no particular preferences. What ever will be the most practical workflow for maintaining image quality throughout, at a price that is not too expensive. Since I unfortunately most definitely fall into the starving artist category.

Thanking you in advance.
Sincerely,
James

[Heath McKnight]

I've had no problems shooting and editing V1u 24p with Final Cut Pro, and removing the pulldown. The thing is, if you go back to tape, even if it's not HDV, FCP will add a pulldown back. You can make a progressive-scan, 24p DVD if you'd like, as well.

heath

[James McCrory]

Okay. What about a capture card, intermediate codec, etc.

Mr. Mullen was recommending using only Vegas for 24P. Does anyone know the reason why?

[Heath McKnight]

You don't need just Vegas; I've been able to use either AIC to capture, edit and remove the pulldown in Final Cut Pro, or converting it to ProRes 422 or whichever non-HDV codec, and creating a QuickTime Movie to remove the pulldown in Cinema Tools.

I wrote about it at VASST (you'll need a free account to read it).

heath

[Kevin Shaw]

Originally Posted by David Tames

Sports looks better in 60i, but stories work better at 24p or 30p.

I know that's the prevailing wisdom, but there's no rational reason to think that makes sense other then it's what we're used to for film-based movies. A good story would work well at 15 fps or 1500 fps; a bad story won't work well at any frame rate.

[Heath McKnight]

The film look is based on 24p/24 fps, depth of field, lighting, costuming, set design and more. The Japanese use 60i for narratives, America, Canada and others use 24p.

Check out our section on Film Looks: http://www.dvinfo.net/conf/forumdisplay.php?f=34

heath

[James McCrory]

Do I need to get one of those expensive capture cards or is that only for capturing footage live uncompressed?

[Douglas Spotted Eagle]

You do not need to get an uncompressed card such as the AJA, Black Magic, or Bluefish product.
Mike Curtis is correct, you should shoot progressive if you want a progressive output. Shooting interlaced and then downconverting to SD and converting HD to SD looks very good, but deinterlacing HD footage looks quite soft. Some folks like this look. I don't happen to be one of them.
As far as sports in 24p or 30p for standard viewing? Try it. Low framerates cause headaches in high action, wide shot sports. It's been tried in several experiments. I was at one set up that Grass Valley (then Thomson) did for the (now) Infinity camcorder. it was terrible, and not one person in the test group could watch basketball in 24p or 30p for any length of time.
Try it for yourself.

[James McCrory]

To Mr. Douglas Spotted Eagle

Thank you Sir for taking the time to respond to my question. Your comments on how low frame rates handle subject matter with a lot of motion was precisely the reason for my initial concern. After conducting some shooting tests however I am now less reluctant to shoot footage progressively. I also wanted to hear if other experienced producers concurred with Mr. Curtis' statement. The answer appears to be yes.

On the issue of workflow: In your opinion is the method outlined by Mr. McKnight in his article, the best one for maintaining the highest quality output for a V1U/ Mac user? What is the difference between the AIC codec and the ProRes codec? Or the Cineform codec?

Are there any advantages or disadvantages to using Vegas over FCP?

Thanking you in advance.
Sincerely,
James

[Douglas Spotted Eagle]

Asking about FCP vs Vegas is a loaded question I'll avoid. I'm a user of both, I tend to use Vegas most of the time. If you're working with 24p and HDV, then there are significant advantages to Vegas over FCP and most other tools.

re; Pro-res, AIC, CineForm. My feeling is that Cineform at any number of levels is the better choice. Much easier to transport, super-high quality codec, format-flat (you can use on both Mac and PC) and it's tried/true. Plus they have tremendous tech support and industry knowledge.