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Sony ENG / EFP Shoulder Mounts
Sony PDW-F800, PDW-700, PDW-850, PXW-X500 (XDCAM HD) and PMW-400, PMW-320 (XDCAM EX).

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Old April 2nd, 2010, 07:25 AM   #1
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More progressive questions

Per recent threads, I've been trying to burn the 30P test footage I shot to Blu-Ray. The problem is, that none of the pull-down menus in either FCP, Vegas, or DVD Architect pro have "30P" as an option It's either 24P or 60i (or the PAL settings).

I've tried to burn BD-R's anyway, but I end up getting stuttering motion. This is new footage I shot in 30P of cars on the street. Not the motion blur issue, but cars that jerk from one frame to the next. I've made sure that all settings are "progressive", but no luck.

Any thoughts on how to proceed? I have not tried shooting in 24P, I am assuming that would be the easiest way, as there are no frame conversion issues.

The next question involves mixing 60i footage into a 24 or 30 P project.

I'm leaving Monday for a shoot, and have decided to plunge into the "P" world, since my distributor demands it. I learned the differences between SD and HD interlace, so there is no reason I can't master progressive as well.

My question is, the first few programs I deliver to them will have to mix some existing interlace with the progressive I am shooting. Not just a few clips here and there, but many minutes.

I know this is a frightful thought, but any ideas on the best route for putting "I" footage into a "P" project? I normally use FCP to edit and DVD Architect Pro to master, but do have access to Vegas (but have barely used it).

Thanks again.
Les Jarrett is offline   Reply With Quote
Old April 2nd, 2010, 10:35 AM   #2
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Les,
You bring up so many issues that one has to conclude that at this point you just lack some experience here. That's not a criticism, for you don't know what you don't know. But here are a few pointers that hopefully add to the understanding.

I am assuming one of the problems you have shooting traffic is the line of traffic moving perpendicular to the lens across the frame rather than to and away, or at some angle.

1.) For 24p, and similarly for 30p the rule is something on the order of 10-20 seconds to pan the frame. Slower is okay, as is panning much (much) faster. What you don't want, is something like 6-15 discrete images of the same object moving across the frame. It should be way more, or way less. It's the window or range that has to be considered.

2.) Shutter speed should be 180-360 degrees usually for natural motion blur. Will probably require added ND in daylight to keep from using small, diffraction limited iris openings. Shooting with added ND and larger iris openings creates a shallower depth of field that also minimizes strobing effects.

3.) This point, often overlooked, an object moves across the frame 16 times faster if the lens is zoomed in 16x, or 16 times slower if zoomed at 1x. Use this to avoid the problem range of 6-15 discrete images of the same object moving across the frame. 3 would be better, as would 30.

As for 30p and Blu-ray, it is and is not a problem. It's true, Blu-ray does not directly support 30p but neither do HDTV television sets. But Blu-ray and many HDTV television sets do natively support 24p, which is helpful, but 24p is even harder than 30p to manage motion judder and strobing since it's 20% slower acquisition. That said, you can with Vegas for instance, encode your output 1080/60i with 30p progressive frames. The Blu ray player if strictly compliant like the PS3 will output this as progressive segmented frames carried within a 1080/60i stream. Many Blu-ray players less compliant, will upconvert the 1080/60i PSF into a 1080/60p progressive output. Either way, it's likely to look the same, differs only in where the upconversion to progressive display happens, either inside the Blu-ray player or inside the HDTV television. But the problem either way for 30p, is that within the conversion the frames are being reinterlaced into PSF for processing before being deinterlaced for display. That leads to the unfortunate effect of adding interlace artifacts into the progressive frames, and it's inescapable. 30p also assures a crappy transfer to PAL if worldwide distribution is being considered. 24p or 25p migrate between the NTSC and PAL systems with only a slight change in speed.

As for mixing interlace and progressive, although I can't speak to the others, with Vegas you start with 24p timeline properties, and drop the 60i onto the same timeline, and just render it out to 24p. The 60i footage will soften slightly, but it still looks reasonably good, and takes on the motion character of 24p. I've done this, and no one has complained.

My $0.02, is it's better to shoot 24p/25p/50i/60i, and avoid 30p. 30p can look good but you keep all your options open with the others.

Although I don't know exactly what the purpose of your footage is, traffic study or filmout, 1080/60i is likely to be the easiest and most versatile format allowing you to capture the most situations with the least amount of complication. Since it's hard to imagine a project that was entirely just shots of street traffic, I might consider 24p for a film look, interviews, dialog or whatever, and shooting the street scenes in 60i and just converting them to 24p on the timeline as described above. Or shoot the whole project in 1080/60i.
Tom Roper is offline   Reply With Quote
Old April 2nd, 2010, 11:41 AM   #3
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Tom,

Thanks so much for your very thoughtful and detailed response. We shoot transportation subjects with the primary focus being trains, but occasionally things such as trucks or aircraft.

I've shot interlace for 30 some years now, and been shooting in 1080i/60 for three and have been very happy with the results. This was all brought on by a distributor who wants progressive.

Some of our scenes will have scenic shots of trains in the distance, but some we'll have a tripod fixed right next to the track when the train goes by. And the steam locomotives with all of their machinery moving. Blur is fine at 60mph, but I did one test shot in progressive three years ago when I got the camera, and the wheels were blurring at 10mph as I was so close to the train.

All the traffic testing is merely the fact that I can take a quick break from the office and running a business and run outside and do some testing.

What I've come up with is that in progressive the motion blur starts to happen just after the center of the screen, and that in interlace it happens a little later in the scene, which for what we are doing is the look I am looking for.

Sorry I've sounded like such a newbie, but I really have been quite happy shooting 60i. Our customers rave about how good the stuff looks. Even the distributors people have raved about it, but somewhere in there they have decided it would look better in progressive.

Again, thanks for the nice response. I think that I'll shoot my steam locomotive on Tuesday in interlace!
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