Shutter Speed of 125 = Sliced Off-Balanced Objects

jrazz wrote on 8/24/2007, 6:16 AM

I shot a dodgeball game at this frame rate and the result was less than desirable. I was trying to compensate for the fast movement of the camera following the ball from one side of the court to the other, but when following the ball, the stationary objects look like someone took a knife, chopped them up and then stacked them off-centered. Here is what I mean: If you were to stack a row of coins and the bottom one was a quarter of the way off center and the next one up was a quarter of the way off center to the right and the next a quarter to the left and so on. This was done with an HVR-A1u.

Any suggestions on how to make this look right? It does not appear this way on the cam's LCD, but after capturing the M2T files to Vegas it does (and after rendering out to mpg and wmv).

j razz

Comments

farss wrote on 8/24/2007, 6:38 AM

I think you're seeing an interlaced scaling problem in Vegas, almost certainly not in the actual footage. You see this 'dogsteeth' problem a lot, even in broadcast material, I always figure they must be using Vegas :)

What is your projects de-interlace method set to?
How are you viewing the footage?

This has probably been there all along, the faster shutter speed has reduced the amount of motion blur that's hidden the problem in the past.

Bob.

jrazz wrote on 8/24/2007, 7:33 AM

Bob, I'll need to check the project settings once I get back to the office. I believe the timeline footage to be upper field first as it is M2T files. I am viewing it on a LCD computer monitor. I have not taken it to the HDTV yet to view.

j razz

jrazz wrote on 8/24/2007, 4:33 PM

M2T File

http://www.jrazzcreations.com//Vegas/Errors/Seeing_Two.JPG

Standard Def Mpg File

http://www.jrazzcreations.com//Vegas/Errors/Stacked_mpg_SD.JPG

This is what I am getting. The M2T file is turning out okay motion-wise on the HDTV. The mpg file is doing what you see above on the HDTV and both are doing exactly what you see above on the PC LCD.

I do have another issue with the M2T file as it has a lot of artifacts. At first I thought it was the gain as it is noisy as I had to compensate for the higher shutter speed, but I noticed that the mpg file did not show this type of noise. Any ideas on that or the first issue posted above?

Edit: you can click on the links to actually read the project properties.
j razz

farss wrote on 8/24/2007, 4:57 PM

Pretty much what I expected to see.

The first two are simply showing you both fields merged. Perfectly normal.

The SD downscale artifacts are the classic 'dogs teeth' problem with Vegas.

Try changing the Deinterlace Method to Interpolate in the project properties. Nomally I use Merge but with that amount of motion I think Interpolate will work better.

Also suggest you get a copy of VLC. It lets you change between various de-interlace methods of the type used in HDTVs such as Weave and Bob. Give you more control than WMP when viewing.

Bob.

jrazz wrote on 8/24/2007, 5:00 PM

Thanks Bob, I will give it a go now.

j razz

jrazz wrote on 8/24/2007, 5:11 PM

That worked: Interpolating the fields. Thanks Bob.

j razz

farss wrote on 8/24/2007, 5:51 PM

Should have mentioned as well to render at Best if not already doing so.
Bob.

jrazz wrote on 8/24/2007, 6:03 PM

I always render to Best. I don't think I have ever used good even when it was default. You have any tips you want to share on fliming/editing something like this? I can always do with learning something new.

j razz

farss wrote on 8/24/2007, 6:37 PM

My best tip, and I did a training DVD of ball games last year.
I'd hired a good cameraman!
He got right IN the action, I was sitting on the sidelines praying his camera insurance was paid up but no sweat, he seems to shoot with both eyes open so he dodged every ball while keeping the camera in focus and the exposure right. Best spend of clients money I've ever made. Of course this guy came with a camera, two lenses and a tripod. That kit cost around $40K back when he bought it and although only SD DVCAM 16:9 it hold up very well today.

Of course you don't have that kind of money so the trick is to know what you're missing out on and do the best to adjust for it.

1) Cheap lenses loose light the longer the focal length. Zoom in to get a tight shot and you can loose 2 to 3 stops. To compensate the camera needs 18dB of gain, yikes, think of the noise!

Solution, get as close to the action as you can, shoot wide(r).

2) Avoid camera shakes and get kit that helps you get the shot by it working with you not distracting you. You haven't got a big shoulder mount broadcast camera and can't afford one. What you might be able to afford is a good tripod and LANC controller. Unlike a camera these things last decades, money well spent. A decent sized LCD monitor with a hood to sit on top of the camera is a big help too. You can watch the whole action / field of play and watch the shot at the same time.

3) We had a big advantage when we shot our ball game video, we were in charge and these were staged events.
Even so though if you're there to cover the event in any remotely official capacity make your needs known. Get the spot that you need for your camera(s), ask for as much light as can be had. Most gyms have wobbly seating, rig something or move your camera(s) so the tripods are on a stable footing. Remember that you being a bit of a pain in the butt will soon be forgotten, your video is for keeps.

4) Keep your cool. In these kinds of events it's very easy to loose the action. The LCD monitor helps but still it can happen. The action will not stop while you compose yourself, panic is bad, just go wide.

5) If using more than one camera don't cross the line. They all have to be on the same side of the court.

6) If you can, stage some shots. Keep a mental note of who scores and afterwards get them to re-enact the shot for some closeups. Even wild shots during practice sessions can come in handy. Might not apply to this kind of game but we did it with soccer like games, get the camera behind the net and get kids to kick the ball into goal. Doesn't even need to be the same player, make the shot short enough and no one will notice.

7) Get some good audio. A wireless mic on the ref is a good idea and some FXs to add a bit of punch. Don't need anything fancy, at a pinch just use your camera's existing mic.

Bob.

jrazz wrote on 8/24/2007, 7:07 PM

Thanks for the ideas Bob.

1) I know exactly what you speak of :)

2) I have been using a monopod as a stabilizer as it has a monfrotto head and arm that I attach a lanc to that I use for zoom only. I shoot with one eye on the LCD and one watching the game... okay, maybe not but I try to.

3) I have freedom to be anywhere on the court I would like. These dodgeball games are for charity and they are happy to have them on tape. The radio station has played several teams so far, but this is the first time I tried using a higher shutter speed. I used to use 2 or 3 cameras back in June but have since gone to just one as all I am making is highlights and with 4 games (20 matches) a week (2 double headers) it makes for some long nights.

4) Good info.

5) I have had 1 guy just doing closeup shots of 1 person to ensure that he would either get a good shot of the person throwing or getting hit so I could use for slow motion purposes. I have had another up on a platform filming at middle court filming the opposite team that I was and I would move around to where ever I felt I could get the best shot- most of the time right behind the person with the ball or about to catch the ball. This allowed for fluidity and we would use a 2 way headset to communicate so we would be filming opposite sides of the court. Of course now I am just using 1 camera and doing a lot of moving.

6) I have been getting some staged shots. I got one of a guy running towards the camera and throwing it. He is a pretty big guy and when I slowed it down... well, I think you can visualize it.

7) I mic'd a player for one game and got some good audio and for another they broadcasted the dodgeball game live and I mic'd the broadcaster. On another I mic'd the ref, but I haven't done any of that since back in June due to time. I am getting a lot of interviews with the players and that makes it interesting as the radio station staff usually talks a lot of smack and the other teams usually say some pretty funny things.

If you want to see some of the videos (13 as of right now) you can go here and view them: http://stage6.divx.com/user/jrazzcreations/videos/tag:dodgeball I don't know if you are familiar with Superstar Dundee, but he was a big wrestler a while back (wrestled with Jerry Lawler) and he was playing for the radio stations team.

j razz