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TimeLapse Technical Notes

Page history last edited by PBworks 16 years, 6 months ago

Chuck's Technical Notes

 


 

This is definitely a work in progress, but here are some tools and techniques that I use for creating Time Lapse videos.

 

Gathering Images

CHDK http://chdk.wikia.com/wiki/CHDK

I have 2 CHDK capable Canon PowerShot Cameras, a S3 IS, and an A560. I typically use CHDK uBasic intervalometer scripts that will just click the shutter forever at some given interval (5-30 seconds, usually).  For the astronomy images, I add a command that adjusts the shutter speed to 65 seconds for each shot.

 

Linux + a Camera

I have a few linux boxes, my current favorite flavor is Ubuntu (7.10)

Digital Camera control using gphoto2 http://gphoto.org

Gphoto/libgphoto is a great linux tool which allows communication and control of a pretty good variety of digital cameras.

Here's information about cameras that gphoto2 can control to do remote image capturing http://www.gphoto.org/doc/remote/

 

Webcam monitoring using motion : http://www.lavrsen.dk/twiki/bin/view/Motion/WebHome

'Motion' can do time lapse and motion detection using any video4linux capable device. This includes many types of webcams or video capture cards. Most of the beavercam images were taken using a video capture card and a security cam. Although before I got the security cam, I just used an old video camera connected to the capture card. I 'weather proofed' it by mounting it on a little platform, and placing a small aquarium on top of it. High tech, I know... There's a pic at the top of the BeaverCam page.

 

Image Processing

Windows based:
IrFanView - a good image viewing/processing program. Pretty good batch mode processing.
A lot can be done on the fly in VirtualDub using filters.
Command-line tools
ImageMagick - Pretty much does everything.

 

 

Video Compilation

    VirtualDub

    Command-Line Processing

       I mostly use perl and imagemagick for processing images...

 

Video Processing/Conversion

    Flash video generation with ffmpeg

   The quality of the flash videos that gets generated automatically by archive.org is good for low bandwidth quick viewing...but not really up to my high standards (haha!).. well, true, I guess... you couldn't really see the hands of the Met Life clock moving in the default version.

Archive.org uses ffmpeg for thier video processing, but the settings they use are tuned for low quality/bandwidth.

Searching around for flv ffmpeg quality settings, this is what I use:

ffmpeg -i InputVideo.avi -f flv -qmax 12 -qmin 12 -s 640x480 -r 29.97 OutputVideo.flv

That gives pretty good results, I guess setting qmax and qmin to the same value allows it to use variable bit-rates, which gives good quality whether there is a lot of motion, or not so much. Setting qmin/qmax to lower values increases quality (and file size) ... 8 seems like a good high quality value...

 

Archive.org also generates the flv at 320x240, so I also increased the size for larger viewing...

 

Once you've regenerated a new flash, I upload that to archive.org using check-out and ftp. You can either replace the original flash video (be careful not to 're-derive' the files, otherwise it will recreate the old version)  OR, you can just save it to a different file name, and point to that when you embed thier little flash player..

 

Hosting Issues

    Archive.org

 

 

 

 

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