Slow Motion Play Back

[richardholt]

Hi,

I am new to making videos - so please excuse my questions if they are not bright.

I am an athletics coach and wish to video my athletes and then play back the video to them in slow motion, hopefully pretty quickly afterwards.

I have been told that it would be best to get a DVD camcorder (so I just move the disk across) and laptop, but I have some DVD footage (am I right in saying this is mpeg4) shot by a friend previously and it doesn't seem to play back in slow motion on my PC (bought DVDs and .wmv files do in Windows Media Player). (Also some mpeg2 video is there which doesn't do slow motion either).

What is going to be the best way for me to do this?

Is there a viewer I can get, which I can play the video on from the disk and just run it in slow motion - I don't mind paying for this if there is (it doesn't need to be freeware etc)

I guess it is possible that I should be looking for a different way of taking the video (I haven't yet bought a camcorder) which will play back in windows media player in slow motion.

Thanks in advance for any help.

[guns1inger]

A simple avisynth script will probably do what you need.

For a simple DV-avi, all you would need is

AVISource("pathtovideo\video.avi").AssumeFPS(n)

Where you fill in the path and file name, and set n to be the speed you want to play back at. 10 fps is pretty good, 5 is very slow. Use Media Player Calssic to playback the script.

I would not get a DVD camcorder, as they tend to not give the clearest pictures when filming motion, so you don't get the detail when you slow it down.

[daamon]

Hi ,

Welcome to the forums.

Slow motion from a DV camera is discussed in detail in this thread:

https://forum.videohelp.com/viewtopic.php?t=303037

I agree with guns1inger about not getting a DVD camcorder for the reason he gives. Also, if you ever get interested in doing more with the camera later, you'd wish you'd got one that records to DV (or maybe even High Definition DV - though they're pricey right now).

A tip: If practical, use a tripod wherever possible - it'll really make a difference to the clarity of the image. Get some good practice before you need to use it on something important - it can take a while to get used to how fast to move it etc.

I hope that helps, and good luck!

[richardholt]

Thanks for the information - it is really helpful.

If I get a DV camera, will it be simple to download the footage to a PC, to be able to show it quickly? Would a USB port be quick enough (I don't have a firewire connection on my Desktop, but could get it on the laptop I am going to buy)

I have tried a previous piece of film from my friends camera in media player classic and that is great - the slow motion is just what I wanted (which I got from the buttons in the player). You are right, however, that the picture isn't all that clear. I will look into the avisynth (which appears to be a programming language to put around videos - is this right - would this be simple and swift to do in a couple of minutes to view?

I was told by a friend that the clarity was down to the shutter speed (which can be adjusted on most cameras?) - is this not the case? I am happy to get any camcorder, provided the download can be down pretty swiftly.

I really appreciate your help - thanks for everything.

P.S. I have a tripod and have used it in the past with my stills camera for mpeg-2 video clips - am wanting the new stuff as the clarity was poor - but at least I can use the tripod!!

[daamon]

If I get a DV camera, will it be simple to download the footage to a PC, to be able to show it quickly?

Yes. Use WinDV - there are others, but this is a good choice.

Would a USB port be quick enough (I don't have a firewire connection on my Desktop, but could get it on the laptop I am going to buy)

No. Use firewire for DV - nothing else.

I will look into the avisynth (which appears to be a programming language to put around videos - is this right - would this be simple and swift to do in a couple of minutes to view?

I've never used Avisynth, but I guess if you got a routine down pat then you'd be able to replay in slow mo quite quickly. Others can comment better...

I was told by a friend that the clarity was down to the shutter speed (which can be adjusted on most cameras?) - is this not the case? I am happy to get any camcorder, provided the download can be down pretty swiftly.

The shutter speed is only one aspect - the fps (or frames per second) is the major one. Think about it - frames per second. The more frames there are per second of video then the better it is to slow it down. Professional film-makers use cameras that can shoot something crazy like 1000's fps for awesoem slow-mo shots.

[guns1inger]

Some newer DV cameras do transfer DV via USB 2, however older cameras have USB 1.1 ports and only transfer low resolution, low quality video. A DV (firewire) card will only cost you $20, and is a worthwhile investment. You can then preview live at speed, or transfer in real time to view in slow motion.

Many DV cameras will have a sports mode, which does give you higher shutter speeds, although there is usually a trade off somewhere else, either in consistency of lighting or smoothness of motion. Your best bet is to audition a couple of cameras before you purchase.

Transfer from DV is in real time - the trade off for quality against the speed of just putting a DVD into a drive. That said, you would still have to copy the files off the DVD to get smooth playback once you start to play with the image.

Avisynth is a frameserver that uses scripts as a front end. It is capable of very powerfully filtering if necessary, but to do what I proposed earlier, for simple real time slow motion playback, all you need is a single line in the script. It is then a matter of simple altering the path and file name in notepad and saving it.

If you want to slow the motion down for distribution, then you will need to use the more advanced plugins and scripts that Daamon linked to, and then encode the results as a new video. This will take substantially longer, as the motion analysis required using that technique is pretty intense and much slower than real time. Each has a place. What I proposed works for immediate viewing and playback, while the other approach is much better for preparing video for distribution or extended study (although my simple script could also be encoded and used as well). You need to look at the output of each approach and go from there.

You will also find that mot editing programs have some form of simple slow motion filter as well. Again, not ideal for immediate playback, but might be OK for encoding.

My strong advice - don't rush in. Check out a couple of different cameras and test them to make sure you get the image quality you want, then spend some time playing to make sure you have a viable solution on your machine when the time comes.

[richardholt]

Thanks for everything - if it won't bore you - I'll let you know how I get on.

[dphirschler]

There are also camcorders that store direct to internal harddrives. Transferring the video to your PC should be faster than realtime on these cameras.


Darryl

[guns1inger]

The problem with these cameras is that like DVD based cameras, they record in mpeg2, and often at lowish bitrates, so the motion images are not as clear as mini-DV. Also, the format they use is not as easy to edit or work with on a PC, and because it is mpeg2 based, it doesn't like being re-encoded as much as DV. DV is still the best non-HD option for home movie recording, by far.

[dphirschler]

Oh! I was not aware of that! Thanks for the scoop, gunslinger. Man, that sucks! Looks like DV is the way to go.


Darryl