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adamsieminski
10-06-2007, 10:38 AM
Hi everyone,
Just wanted to make a post to let people know that I'm writing a series of articles on improving your tennis video skills, whether you are filming yourself, or filming someone else. It's going to be a multipart series, and my goal was to explain things in very plain english.

Part 1 is online now, and it focuses on understanding frame rates and interlacing, and how those two things affect your tennis video.

Hope people enjoy. I've also posted this note on the "getting the most from your tennis video" sticky.

Adam Sieminski

adamsieminski
10-06-2007, 10:39 AM
I suppose it would help if I included the link. =)http://www.fuzzyyellowballs.com/getting_the_most.php

StealthGnome
10-06-2007, 02:07 PM
Very informative.
Looking forward to the whole article.

Tennis_Monk
10-06-2007, 07:39 PM
Good Article. Looking forward for more..

lkdog
10-07-2007, 06:33 AM
Interesting. You guys have a creative team over there.

Mike Cottrill
10-07-2007, 07:37 AM
Nice intro Adam. Keep it comming.

WildVolley
10-08-2007, 10:55 AM
Very nice article. To try to summarize it, you've explained that the best we're going to be able to do is 30 frames a second with a normally priced video camera, or we may be able to capture 60 frames with only half the information (much lower quality per each frame)?

Someone needs to develop an inexpensive camera with a chip that will capture at least 60 frames or higher, that would be used just for sports. That would be great.

Mike Cottrill
10-08-2007, 05:00 PM
Very nice article. To try to summarize it, you've explained that the best we're going to be able to do is 30 frames a second with a normally priced video camera, or we may be able to capture 60 frames with only half the information (much lower quality per each frame)?

Someone needs to develop an inexpensive camera with a chip that will capture at least 60 frames or higher, that would be used just for sports. That would be great.

Wild,
The only camera that I know of that will record more than 30fps or 60 fields for less than 1K is some of the Sony cameras. Those will record 240fps for 3 seconds. For example the DVD508. The problem with Sony consumer camcorder is that they do not let you control the shutter speed. It appears the fastest shutter is around 1/500sec which give you blur. However, I still find it very usefull.

Mike

WildVolley
10-08-2007, 06:51 PM
Wild,
The only camera that I know of that will record more than 30fps or 60 fields for less than 1K is some of the Sony cameras. Those will record 240fps for 3 seconds. For example the DVD508. The problem with Sony consumer camcorder is that they do not let you control the shutter speed. It appears the fastest shutter is around 1/500sec which give you blur. However, I still find it very usefull.

Mike

3 seconds isn't very long, but it would be enough time to catch a serve or other hit in detail. Is it difficult for you to get those 3-seconds started just when you want (I mean, is there a lag with the start button)?

Too bad they don't allow the faster shutter speed. With faster shutter speed, you could catch really crisp images in direct sunlight.

I really know little about the technical requirements of making a DV-camera that would capture at a faster rate. Is Sony the only company that's producing inexpensive chips that can capture at 240fps? I guess most companies are not making cameras aimed at the sports market.

adamsieminski
10-08-2007, 07:53 PM
Thanks for the feedback so far guys. Part 2 should be up tomorrow.

Part of the limitation on making a cheap consumer camcorder that can record 200+ FPS is that the camcorder has to record the image video to some kind of media. In a DV tape camcorcer, there is a physical reel of tape that goes around. The tape only spins so fast, so there is a limit to the amount of data that can be recorded per second. The current uncompressed DV format writes so much data to the tape (DV writes 25 megabits per second for a standard definition signal... compare that to 9MBPS for some newer MPEG-4 High Definition formats) that it's very close to tape's maximum write ability.

So, you can write 200 FPS to tape, but those frames just can't contain nearly as much information as a normal DV frame would contain. ie, you have to reduce the resolution and color space to fit 200 frames into the same space as 30 normal DV frames.

Tape is cheap.

You can make a camera that records to solid state media, which can write a lot of information very fast. Think like recording to a Compact Flash (CF) or Secure Digital (SD) card. That kind of memory isnt cheap! And realistically, even with say, a 16GB CF card inside your camcorder, that might hold several minutes of high quality footage... Maybe 30 seconds seconds of high quality, high-speed footage.

But who would really buy a consumer-level camcorder that could only shoot 2 minutes worth of video? Thats why tape still sticks around. Its just so cheap, and the DV format produces a nice looking picture.

Hard drive camcorders probably hold the best future possibilty for cheap high-speed footage. The only problem left to overcome is this: When you go to make a camcorder, you have to spend money to pay for the programmers to program the camera to be capable of shooting in a 200fps mode. You have to pay for the special computer chips that can control the camera and direct it to shoot in a 200fps mode.

None of that stuff is off-the-shelf, and my guess is that the increased production costs don't really jive with any camcorder manufacturer's marginal profit curve charts.

I might cover all this in more detail in a later part in the series =)

Adam

wihamilton
10-08-2007, 09:09 PM
nerd.

that would have been the end of my msg but apparently a post has to be at least 10 characters long.

Mike Cottrill
10-08-2007, 09:11 PM
3 seconds isn't very long, but it would be enough time to catch a serve or other hit in detail. Is it difficult for you to get those 3-seconds started just when you want (I mean, is there a lag with the start button)?

No more lag than with normal mode. You can pre or post trigger. 3 seconds is enough time to capture a complete stroke of any kind, just no rallies. The issue is that once the capture is completed, it takes a significant amount of time to flush the buffer (~12 seconds) to the storage device and the camera can not capture more video until that is complete. To record yourself, it is easier to have someone man the camera.



Too bad they don't allow the faster shutter speed. With faster shutter speed, you could catch really crisp images in direct sunlight.

So true. Somthing Sony could do, but will not.


I really know little about the technical requirements of making a DV-camera that would capture at a faster rate. Is Sony the only company that's producing inexpensive chips that can capture at 240fps? I guess most companies are not making cameras aimed at the sports market.

As far as I know, Sony is the only camcorder in the consumer market with this feature.
From my understanding, media storage is not the bottle neck with capturing high speed video with the Sony CMOS camcorder, it is the EIP (Enhanced Imaging Processor) that process the data off the sensor.

I believe Sony has a more expensive model out now that can record up to 12 seconds at that frame rate.

Also, I forgot to mention that the resolution is reduced in this mode. The amateur movie makers complained about this when the camera came out. They wanted to use it for special effect, but slicing in the clip into the normal video does not turn out to well.

The cheapest dedicated high speed camera I have seen (max 500fps) is a professional camera and comes in at 4.9K with software.. Max resolution is 640X480. I think you can remotely control it with a laptop. As you surpass this handheld, more setup is required.

Time to get back to tennis.

odessa
10-09-2007, 01:52 PM
Hi everyone,
Just wanted to make a post to let people know that I'm writing a series of articles on improving your tennis video skills, whether you are filming yourself, or filming someone else. It's going to be a multipart series, and my goal was to explain things in very plain english.

Part 1 is online now, and it focuses on understanding frame rates and interlacing, and how those two things affect your tennis video.

Hope people enjoy. I've also posted this note on the "getting the most from your tennis video" sticky.

Adam Sieminski

In your article you write about the possibiilty to produce 60 fps video from a 60i video. But you say your on results with this method were not so good.
But how does someone get the picture quality from hi-techtennis,com ?
Jeffery is using a old and cheap canon camcorder and is producing great quality 60 fps video or is this video half resolution (if so it doesnt matter do me) ?
There are a couple of free samples on his website.
If you can give me your best guess how you can produce videos like this it would be great.
http://hitechtennis.com/

adamsieminski
10-10-2007, 07:43 AM
Odessa,
I can't really speculate on methods that a webmaster might use, it simply wouldn't be my place to do so. If Jeff would like to chime in, he is welcome to!

As for producing 60p video from a 60i camcorder, later in my series I will show you how to use some free software to achieve this. Then you can give it a shot yourself!

Adam

Mike Cottrill
10-10-2007, 05:23 PM
Odessa,
I can't really speculate on methods that a webmaster might use, it simply wouldn't be my place to do so. If Jeff would like to chime in, he is welcome to!

As for producing 60p video from a 60i camcorder, later in my series I will show you how to use some free software to achieve this. Then you can give it a shot yourself!

Adam

As a lead in to your next article, would this be VirtualDub and AviSynth?

wihamilton
10-11-2007, 07:16 AM
Part 2 is up.

adamsieminski
10-11-2007, 09:05 AM
As a lead in to your next article, would this be VirtualDub and AviSynth?

All in good time, Mike... all in good time =) There's a lot I'm going to cover before I get to this aspect.

Mike Cottrill
10-11-2007, 09:14 AM
Patiently waiting.,,

"Most consumer camcorders allow you to manually control the size of the lens aperture."

To bad Sony does not take note.