16 Topic by Chas Tennis

(7 replies, posted in General)

Kinovea Analyses on Vimeo

We often may want to communicate the Kinovea analyses videos using Youtube, Vimeo or other video web hosts.

This issue probably involves Vimeo website processing and I have not asked them yet.   I believe that Vimeo added single frame advance capability about 3 years ago. 

I cannot now recall some details so I'm not asking for a fix. Asking generally, how can I document problems with Vimeo processed Kinovea analysis videos in the future? 

I have uploaded some videos on Vimeo.   The Kinovea analysis videos worked well on my computer. They were side-by-side videos, each video recorded at different frame rates, 240 & 30 fps often,  with magnification boxes and millisecond countdown time displays.  Very informative displays.

1) sometimes the magnification boxes appeared on Vimeo in different screen locations than in my computer video.  In the wrong place, they blocked video and often obscured the labels, arrows etc that were on the screen.

I discarded the videos where the magnification box obscured something and am not now sure what might have been happening. It seems to work better lately but I worry about it. 

Why would everything be in place but the magnification box? 

Also, once a magnification box is introduced it stays throughout the video, start to finish. It would be a plus if they could be put in and removed for any ranges of frames.

2) often the Vimeo processed video would do single frame so that the faster video (say 240 fps) would advance 2 frames using the Vimeo process for single frame advance.

Vimeo single frame process - Hold down SHIFT KEY & use ARROW KEYS

This side-by-side video works well, magnification box is good, but the high speed video on the right advances 2 frame times each time the arrow is pressed. (8.4 milliseconds per Vimeo arrow press instead of 4.2 ms.) This video has very brief messages and is intended to stop on specific single frames when messages appear. Not a useful video for 30 fps playback.
[video]https://vimeo.com/203003367[/video]

I am so pleased with the great job that Kinovea does on these videos.  That Vimeo video is so near perfect except it advances 2 frames on Vimeo for every one frame advance key press.

I believe that I had set the video speed properly to 240 fps when making the Kinovea analysis video.

Might it work better if I put the 240 fps video to the left?  Probably a Vimeo processing or playback issue?

FYI - After years of suffering to advance one frame on Youtube, I just learned that Youtube single frame exists - you simply use the "." and ","  keys!!  Oh, that hurts!

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17 Topic by Chas Tennis

(2 replies, posted in Bug reports)

I wanted to compare, side-by-side, a tennis server that is left handed with another that is right handed. To make the rightie look like a leftie, I used the "Mirror" function and it worked very well.  Saved the video as an mkv file and it worked well.  (The 'mirrored' video is on the right and is as it should be.)

mkv- Worked well.
https://vimeo.com/197541582

When I tried to use the "Mirror" with just one video it looked fine on Kinovea.  But when I saved it as an mp4 file it had reverted back to its original right-left orientation.  The magnification boxes  in the saved video seem to be in the original positions seen in Kinovea.  But after the video is saved the magnifier selection box has not moved and is blank but the display box has the correct video of the player's elbow as when viewing in Kinovea.  Videos that worked well in Kinovea now lost the effect of 'Mirror' after saving as a video file.   Kinovea reversed the right-left with 'Mirror' but after saving the original right-left reappeared. 

mp4 Failed.
https://vimeo.com/197566232

mkv Failed
https://vimeo.com/197600108

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18 Reply by Chas Tennis

(44 replies, posted in General)

First time using 8.25 - this question involves the use of the stopwatch "countdown mode" for displaying time or frame.

For side-by-side tennis strokes I would like to display "0" time for racket-ball impact with negative values of time before impact and positive after.  I would like these to appear in a video for Vimeo or Youtube and not just on the Kinovea analysis screen.

First pair of videos were: 1) 29.97 fps recording & 29.97 playback and 2) a high frame rate recording described as "240" fps and processed in the Casio camera to 29.97 fps playback video.  The 29.97 fps rates appeared automatically for one video. I entered the 240 fps recording rate for the high speed recording video. 

Positive Time works well. I used the millisecond time scale for each video, coordinated the impact frames between the two videos and each video has a time indicator displaying positive time after impact.   On the Kinovea analysis screen, one video advanced 33.33 milliseconds each time the combined control single frame advanced and the other 4.2 milliseconds. 

Negatve Time before impact. I am having no luck adding the stopwatch "countdown mode" to the display.  If I select "stop stopwatch" and "countdown mode" only one frame displays "0" at impact - no countdown to "0".  Search under Help did not have information for "countdown mode."

On the Kinovea analysis screen, next to the speed bar, I see "Position" and it lists the negative millisecond values that I am trying to display in the video.

Unfortunately also, when I uploaded this Kinovea side-by-side, 30 & 240 fps video to Vimeo, the Vimeo processing seems to have kept only one frame in four from the original 240 fps video.   
[video]https://vimeo.com/193082298[/video]

To do stop action single frame on Vimeo, click Vimeo then full screen, hold down the SHIFT KEY and use the ARROW KEYS.

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19 Reply by Chas Tennis

(2 replies, posted in General)

I am interested in having 8.15 and 8.25 both on my computer also.

There were two posts that mentioned having both versions on the same computer but the terms used were not familiar to me.

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20 Topic by Chas Tennis

(1 replies, posted in General)

One application that I am interested in is comparing tennis strokes on side-by-side screens.  I often have video clips of a tennis server and want to compare them to high level severs side-by-side.   

Sometimes the videos have been downloaded from Youtube, Vimeo or other sources.  Sometimes the recording rates stated by the originator of the video are questionable. So I want to better understand how Kinovea handles timing for side-by-side videos.

I'm using Kinovea version 8.15. If a later version has improvements for coordinating time scales on side-by-side videos, please mention.

In tennis, some researchers use a time scale with ball-racket impact as time zero.  Time or frame count values before impact are negative and those after impact are positive. I want to display positive and negative frames & times in this way but have not found a way to display negative frame rates or times. I have counted back from impact many frames, 130 frames, and placed the zero frame there but would prefer using negative values before impact.

Example of a very informative time scale, displaying joint motions for a tennis serve using impact at time zero.  Impact at zero seems appropriate for all striking sports so negative frames and times would be an informative number for Kinovea to display. 
http://g4.img-dpreview.com/70E9CDAB577B4335859535EAF3EF5940.jpg

Just starting these side-by-side comparisons. I recently analyzed an iPad Air 2 video 'recorded at 120 fps' and another video recorded at 240 fps. When I enter 120 fps for the iPad camera and 240 fps for the other, the ball seems to reach the same positions after impact frame for frame.  That's confusing. ? Was the one serve twice as fast as the other?  I guess that Kinovea simply assumes that all frames originally recorded are present in the video being analyzed. ? 

Can the entered recording frame rate be changed at any time during analyzing the video? Or does it become locked at some point, say, after the first key image has been saved?   

----------------------------------------------------------------
Information in Kinovea 8.15 "Help".

http://www.kinovea.org/help/en/115.html

"Configuring for high-speed cameras

High-speed capture - Slow motion playback

High-speed camera record videos at a very high frame rate and store them in a video file with a normal frame rate.
For example, a high-speed camera may record images at 1000 frames per seconds and create a video specifying that it should be displayed at 30 frames per seconds.
When played back, the video will appear in slow motion.

By default, the times displayed in Kinovea are based on the playback frame rate, since it is the only information encoded in the video.
Hence, when playing back a video captured with a high-speed camera, the times displayed will not match the captured event time.

You can specify the capture frame rate of the high-speed camera by right clicking the image to bring the main contextual menu and then use Set Original Speed…


Configuring the high-speed camera recording frame rate.

All time-related informations displayed in Kinovea will use this information (i.e: current position, working zone duration, stopwatches, etc.)."

Motion - high speed video -
http://www.kinovea.org/help/en/115-highspeedcameras.png

---------------------------------------------------

I've noticed that the frame counts can be off between the two windows if I start and stop the video rapidly.  I assume that is a computer processing time issue. ?  If I slowly press the pause control to advance single frame, the frame counts compare in a more well behaved way.  Suggestions to users when frame rates do not agree when advanced rapidly?


[Someone mentioned a way to roughly measure video frame rates.  Was the frame rate 25 fps, 30 fps, 200 fps, 240 fps, etc.?  I believe that if a ball is bounced and the peak of the bounce is videoed for a particular type ball, it will always drop a certain number of diameters in a given time.  For example, a  tennis ball or soccer ball, etc. could be used as a time reference and may even appear incidentally in a video. This time reference might be useful for double checking video frame rates.  For example, videos could be made showing the peak of a tennis ball bounce for different video frame rates.

Some smartphones are said to change frame rates in low light, to use slower frame rates to collect more light.]

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21 Reply by Chas Tennis

(51 replies, posted in Cameras and hardware)

I find this information especially useful for examining Youtube and Vimeo videos and estimating the light levels that the videos were shot in.  This approach especially helps estimate the unknown fastest shutter speeds in direct sunlight for video cameras with automatic exposure control.  The motion blur is an indication of the shutter speed.

You can see some things from the shadows in pictures.

1) the shadow of the drink.
2) the shadow of the golfer.
3) the tree line illumination.

In post #49, the sun is behind the golfer.  The drinking cup shadow gives a more accurate indication of where the sun is.  The sun also does not shine on the tree line. 

But the club itself goes in and out of the golfer's leg shadows so various illuminations from direct sunlight to indirect occur. (I believe that illumination in most shadows is called 'skylight' and there's always some other miscellaneous reflected illumination.)  The golf club can be seen in the leg shadows.

Sunlight vs Skylight. See section 2.1
http://web.stanford.edu/group/narrative … design.pdf

The edges of the shadows are sharp. I interpret sharp edges to mean that the sun light is not diffused by overcast skies.

The golf club is painted black and has a smooth surface.  At parts of the swing, I believe you can even see a specular reflection of the sun from the smooth cylindrical surface on the top of the club and black on the bottom of the club. 

Regarding low light capabilities, for my Casio FH100, the camera can expose at 1/40,000 sec on a sunny day and still get an adequate exposure in the shadows (from skylight and other reflections). 
https://vimeo.com/26480215

Overcast skies provide less light but often still enough for very fast shutter speeds, 1/5000 sec?,  with the Casio Ex FH100 and maybe the Casio Ex 100f also. ?

Indoor lighting of tennis courts has a light level only about 1% of direct sunlight.  Those light levels are from published data and are discussed in a post earlier.  Shutter speeds of 1/1000 sec may not have enough exposure.
http://www.kinovea.org/en/forum/viewtop … 2033#p2033

I examined the 100f video file on my computer and it looks better than the Youtube version.  That is usually the case also with my low resolution Casio FH100 videos on Vimeo.  I don't know if the small loss in quality is the Youtube or Vimeo compression or pixel count changes in the format's number of pixels.  I like Vimeo because it advances single frame on Vimeo without downloading. 

Use direct sunlight if you can!

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22 Reply by Chas Tennis

(51 replies, posted in Cameras and hardware)

Casio Ex 100f - the user's manual indicates that the camera has manual exposure control and a 1/10,000 sec shutter speed. 

I have no experience with this camera.  I have not found Ex 100f user's high speed videos on Youtube to evaluate the shutter speed and motion blur.   

I first heard about the Ex f100 in a dpreview thread. I missed the first announcements in Aug 2015, as a model available in Japan.  See subsequent posts following this post.
http://www.dpreview.com/forums/post/57666381

An Ex 100f user's manual is available from Casio Support:
http://support.casio.com/storage/en/man … 116_EN.pdf

For high speed video and manual shutter settings, the user's manual has this -

Quote -
"Using BEST SHOT Use the procedure below to shoot a High Speed Movie with manually configured aperture and shutter speed settings. The ability to manually adjust shutter speed helps to reduce image blur due to subject movement.

1.In the BEST SHOT Mode, select “Manual Exposure Movie” (page 93).

2.Press [SET].

3.Use [8] and [2] to select (Aperture) and then press [SET].

4.Use [8] and [2] to select an aperture setting and then press [4].

5.Use [8] and [2] to select (Shutter Speed) and then press [SET].

6.Use [8] and [2] to select a shutter speed and then press [SET].

7.Press [0] (Movie) to start recording.

8.Press [0] (Movie) again to stop recording.

The maximum file size allowed for a single movie file is 4GB. Movie recording stops automatically when the file size becomes 4GB.

NOTE• The settings below can be configured while shooting with this function.

Movie Quality: HS120, HS240, HS480, HS1000

Shutter Speed: Auto, 1/125 to 1/10000 seconds(The actual available setting range depends on the movie quality setting.)

ISO Sensitivity: Auto, ISO80 to ISO3200(The actual available setting range depends on the shutter speed and aperture.)•

The functions below cannot be used with this functionAnti-shake Functions, Single SR Zoom, Face Detection, Make-up, Triple Se................."

"HS1000
(224x64)
(1000 frames/second)
13 minutes 10 seconds

HS480
(224x160)
(480 frames/second)
13 minutes

HS240
(512x384)
(240 frames/second)
12 minutes  58 seconds

HS120
(640x480)
(120 frames/second)
12 minutes 55 seconds"

Information on this camera is not easy to find. Using "100f" helped my search.  If you find some Ex 100f Youtubes that display high speed video modes and motion blur (no splashing water videos please) please post.  If you have an f100 please test it in high speed video mode with fast shutter speeds and post some of your videos.   Motion blur info please....

Also, the Jello Effect distortions of this camera need to be evaluated.

(The Ex 100f camera may be related to another Casio model, the Ex 100pro discussed in an earlier post, #44. Apparently a false alarm as first there were announcements in Dec 2014 and then nothing. ? I have not found farther information, on shutter speed, etc. of the high speed video modes of the Ex 100pro camera. (Only Casio-produced high speed videos were shown, no user's high speed videos seem available.)   

The Casio Ex 100f camera is offered on Amzn.

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23 Reply by Chas Tennis

(2 replies, posted in Ideas and feature requests)

Rolling Shutter and Jello Effect Distortion

Most video cameras now sold are CMOS based.  They use an electronic readout called a "rolling shutter' to read the light signals from the sensor array.  They read one sensor line of elemental detectors at a time.  This results in a time delay from the first sensor line read to the later lines read.  The resulting image distortion is called "Jello Effect', it occurs for video frames and stills.

This issue should be evaluated as dogs imaged in one part of the frame may be seen behind those recorded in another part of the frame. For example, if you look along the finish line the dogs at the top of the frame may be imaged at an earlier time than those at the bottom of the frame. 

CCD based cameras with Global Shutters do not usually have this delay.

I measured some of these Jello Effect distortions for three CMOS video cameras, a Casio FH100 (240 fps), an Aiptek Action HD camera, 60 fps and a Canon Powershot 110 HS (30 fps).  See descriptions on Vimeo.

Casio Ex FH100 (240 fps), Jello Effect.  White line is straight.
https://vimeo.com/25242212

Aiptek Action HD (60 fps), Jello Effect. The black line is straight and parallel to the sides of the cylinder.
https://vimeo.com/30281692

Canon Powershot 110 HS (30 fps), Jello Effect. Black line is straight.
https://vimeo.com/72531589

Still picture with Jello Effect distortion. All blades of this fan are straight but two appear bent. The top blade was read out first - at an earlier time. It and the bottom blade are falsely bent.  For the horizontal blades one is widened and one has been made narrower. The one widened is moving in the direction of the rolling shutter scan and the one made narrower is moving against the scan direction. 
http://g1.img-dpreview.com/306AD1587A954231A81D344CCDC06012.jpg

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24 Reply by Chas Tennis

(51 replies, posted in Cameras and hardware)

Recent website that specializes in high speed video cameras. 
http://hispeedcams.com/

It is always easy to find the frame rates and resolutions for high speed video.

It is usually more difficult to find information on:
1) whether automatic exposure control or manual exposure control
2) shutter speeds and resulting motion blur
3) total recording time - some cameras record for just a few seconds
4) Jello Effect distortion
5) other specifications and features that may be important for some applications

I just started reading some of the camera reviews. The reviews seem to have more information on the above subjects.
--------------------------------------------------------------------
UPDATE - 2016-Jun 10. After a year, I've been a little disappointed in the information presented for these reasons:
1) A considerable percent of the camera reviews relate to rumors or claims concerning capabilities that a camera may have in the future instead of to cameras now available with those capabilities.
2) I suggested review of the Casio Ex f100 with manual exposure control but learned that it does not have high enough resolution in high speed video mode to qualify for a review.  Certain very capable high speed video cameras may not be reviewed because of resolution.
3) For video analysis the issue of motion blur is very important, but I'm still not able to find shutter speed information.  Typically, review videos are not presented that display motion blur very well. 

The site is still outstanding for showing many new cameras with higher resolution in high speed video modes.   

But for analysis some very capable cameras with manual exposure control or automatic exposure control for very fast shutters and zoom lenses may not be reviewed because of hispeedcams's resolution cutoff policy.

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25 Reply by Chas Tennis

(3 replies, posted in Ideas and feature requests)

In tennis it is often said that a very effective drill for serving is throwing.  I wanted to find the basis of this and would look for the reason why.  I knew the basis is that the drill should include internal shoulder rotation, a rotation of the upper arm.  I was watching an instructional video on the throw as a drill for the serve and decided to do stop frame on the thrower and server.

http://images2.snapfish.com/232323232%7Ffp83232%3Euqcshlukaxroqdfv%3B%3C%3B6%3Dot%3E83%3A6%3D44%3A%3D348%3DXROQDF%3E2823%3A%3A48%3B%3B257ot1lsi

By luck, this frame appears to be from interlaced video. The double images (one from each video field) are 16 milliseconds apart.  The upper arm is rotating the forearm to get hand speed. It worked especially well because the upper arm is rotating the forearm faster than other body parts are moving.

For the serve, the upper arm is rotating the racket at an angle to the forehand for racket head speed.
http://images2.snapfish.com/232323232%7Ffp83232%3Euqcshlukaxroqdfv6%3B%3A7%3Dot%3E83%3A6%3D44%3A%3D348%3DXROQDF%3E2854%3A32643257ot1lsi

I was impressed at how informative a double image could be. 

I'd like to try looking at videos where, say, a before, the current and an after frame appeared together.

For the moving camera issue, if the camera is hand held and pointing at slightly different directions if something in the background can be identified it might be used to index frames together.   That approach depends on a small pointing angle variation not what you would get walking along holding a camera.

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26 Reply by Chas Tennis

(3 replies, posted in Cameras and hardware)

* Fast Shutter Speed for Small Motion Blur. (Estimated Motion Blur = V x T, where V is object velocity across the frame and T is the shutter speed.)

* 3D Multi-Camera Motion Capture Systems can measure in 3 dimensions, but at very high cost.  I believe that in some applications, 2 cameras might be applied to produce 3D measurements but with limitations under some circumstances.  For example, a golf swing might be a suitable subject for 3D measurements with 2 cameras where a tennis serve, more 3D, might not be because markers become obscured (require multicamera systems). I don't know the limitations, maybe 2 cameras would be feasible for many applications?     

* Cameras that produce orthogonal views are very useful for qualitative 3D analysis.  I'd always like to see the same tennis stroke in orthogonal XY plane and XZ planes, even if I could not measure it. 

UPDATE - NOTE THE SCANT INFORMATION I'VE SEEN ON THIS NEW CAMERA'S HIGH SPEED VIDEO IS NOT CLEAR -
The new Casio Ex 100Pro camera, reported to have manual shutter control, has a capability to operate 7 cameras from a WiFi trigger and have the high speed frames coordinated to within 1/2 millisecond.   That is according to preliminary information before its Jan 15th 2015 release in Japan.  I have been looking for Youtubes to evaluate the motion blur but have not seen any except the early Casio 100Pro Youtubes.

* I believe that multi-images -  in some form - can provide much better comparisons for rapid athletic motions than viewing in slow motion or stepping through single frames and trying to remember what you have seen. http://www.kinovea.org/en/forum/viewtopic.php?id=760

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27 Topic by Chas Tennis

(3 replies, posted in Ideas and feature requests)

I have found that pictures such as the following are very informative for athletic motions, especially to show arms, balls, rackets, etc.   However, these pictures are produced by manually selecting portions of high speed video frames and using Photoshop layering to assemble the composite.  I don't do them myself so I can't say how much time is involved to produce a composite picture from a series of frames from a high speed video.

Chas Tennis wrote:

These composite pictures of selected video frames are being posted lately in the Tennis Talk Forum by Anatoly Antipin ("Toly"). 

In a Tennis Talk forum reply he says that he uses Kinovea to select single frames, convert and save as .jpeg. He then uses Photoshop and Powerpoint.  He uses the Photoshop multiple layers technique.  I don't produce these myself so I can't provide much more information on the process.

These pictures are one of the best ways that I've seen for showing athletic motions. I'm noticing things that I never noticed before. Especially, the rare Fuzzy Yellow Balls videos of the server taken from above show some very interesting details.   Also, where shown, the ball on its trajectory and the camera frame rate can provide timing. See the ball's trajectory and ball spacing in the tennis serve. 

If anyone has samples of similar display methods, please post along with some of your techniques.


http://i1.ytimg.com/vi/QUwxiqFUi58/hqdefault.jpg

Youtube from Anatoly Anitipin showing composite of selected video frames as part of the video. 
http://www.youtube.com/watch?v=QUwxiqFUi58
Videos
http://www.youtube.com/channel/UCVtnV90bBCB50nkd8EQDFOQ


Some other composite pictures of video frames. 

http://i43.tinypic.com/2w3qibr.jpg
Stosur toss and impact location.


http://i46.tinypic.com/s3kmxx.jpg
Rare serves from above showing racket and hand movement.  See FYB Youtube videos. http://www.youtube.com/watch?v=2FpeYGG9XAg    and others from above.


http://i47.tinypic.com/x5y53s.jpg
Serve showing when racket goes from edge-on to the ball to impact, lasts ~ 0.02 second, and some of the follow through.  This is the internal shoulder rotation that contributes the most to racket head speed at impact.


http://i44.tinypic.com/jsdsgj.jpg
Composite picture of Roger Federer forehand.

I discussed the issue with someone who mentioned a video processing technique that saves, for example, the brightest pixel occurring in a series of video frames.  For example, suppose a tennis ball travels with a tennis court as the dark background.   The processing would see the tennis ball as the brightest pixels at a different location for each frame, save for each frame and display all ball images in a later composite video or still.  If the frames were made into a composite picture the trajectory of the ball is shown and the distance between the ball images gives an indication of time or velocity.  Tracking does not do that.  This result, in theory, could produce results similar to the above composite pictures, but the result would be produced by the computer and not manually.

The technique might also work for saving the lowest brightness pixels from a series of frames.  Dark objects on light backgrounds would be the best candidates.   

This technique has been applied especially to some soccer where the ball's trajectory appears.   

https://www.youtube.com/watch?v=l7l5YKssHPg

[video]https://www.youtube.com/watch?v=l7l5YKssHPg[/video]
http://fcl.uncc.edu/nhnguye1/balltracking.html

Also, since in athletics most objects move in one direction, saving or processing the forward edge of most objects might be informative and allow more frames to be displayed.  This has been done in the composite frames above by manually layering using Photoshop.  Transparency and colors might be useful capabilities.

Often a video frame or still that shows just 3 frames - the current frame along with object positions of the frame before and after (color coded? transparent?) can be very informative. If objects from the frame before and after were always also displayed, it would make important observations more apparent. When stop action single frame is normally used you have to remember the positions instead of seeing them.   

If anyone has related links or experience in this topic, please post.

The main idea would be to produce informative video or still composite displays like those above but without the time required by the manual processing.

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28 Reply by Chas Tennis

(51 replies, posted in Cameras and hardware)

UPDATE - As of 3/3/2015 I have not been able to find information on the high speed video capabilities of this camera.  I do not know if the coordination of several cameras with WiFi applies to high speed video mode.

UPDATE - As of 6/24/2015 - I have not found whether this camera has manual exposure control or the shutter speeds. ?? From viewing videos of a wine glass breaking and others, I do now believe that the multi-camera high speed video operation applies to up to 7 cameras.

If you learn anything please provide some links. 


Casio Ex 100Pro

Just heard today about a new camera - researching it now especially the mention that it might have manual exposure control and a very fast shutter.

http://www.dpreview.com/forums/post/54968131

http://petapixel.com/2014/12/18/casio-s … d-capture/

Youtube, coordination of several cameras -
https://www.youtube.com/watch?v=wrhJjkpgBDM

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29 Reply by Chas Tennis

(2 replies, posted in General)

joan wrote:

Link to website : http://slowmovideo.granjow.net/

.......................................You can basically map the input time (vertical axis) to the output time (horizontal axis) in any way you want, to create slow, static, fast, reverse motion.
........................................................
I don't know if it would be useful to have this type of slow motion at analysis time since the frames are built from scratch and will not give you any information you are missing. For qualitative analysis it may be more pleasing to watch and help feeling the movement better. ......................................

For analysis - I vote against any analysis of post processed videos with frames containing created object positions.

I look at tennis serve videos.  Recently, I believe that Youtube has a slow motion option for some videos.  Analyzing a 30 fps (or 25 fps) recorded video that has somehow been processed to create additional false frames for 30 fps playback is counterproductive for analysis and might lead to false conclusions. 

Videos with post-processed-created false object positions should be identified.  When asked what the post processing might have been, most posters don't know or respond. 

For entertainment, especially where the video will be played back at 30 fps and no one will do stop-action single-frame for analysis, the post processed videos can display fast actions in a more viewable way. 

To keep things clear it helps, for example, to specify a video recoded at 240 fps for video playback at 30 fps.  The video recording rate determines all the information that you have for analysis.   But if additional frames are created by post processing there is a disconnect, which frames are false?

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30 Reply by Chas Tennis

(27 replies, posted in Cameras and hardware)

The subjects look well framed and attractive.  For 30 fps video playback the videos probably will work well.

However, to examine the frames stop-action single-frame, the limitations on the camera that cause motion blur should be improved. 

Action frame
http://images2.snapfish.com/232323232%7Ffp83232%3Euqcshlukaxroqdfv3%3A68%3Dot%3E83%3A6%3D44%3A%3D348%3DXROQDF%3E285777757%3C257ot1lsi

This frame has excessive motion blur.   The video was taken in overcast lighting conditions as no sharp shadows are showing. [In direct sunlight you will see sharp shadows.]  In direct sunlight, with several times more light, the camera's automatic exposure control may choose a faster shutter and reduce the motion blur.  (I have assumed that your camera does not have a way to manually set the shutter speed.)

The thread Basic Camera Considerations and Cameras has discussion of frame rate, shutter speed and motion blur.   
http://www.kinovea.org/en/forum/viewtopic.php?id=435

How important is stop-action single-frame for your application relative to 30 fps playback?

There are many cameras now that record at 60 fps and have fast shutters, certainly in direct sunlight, either automatic exposure control or manual exposure control.  Especially some recent DSLR camera models will allow manual shutter speed setting.

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