Time-Lapse Video

This page will explain my method for making the Time-Lapse Videos that can be seen on the Videos page.

I use a Fuji F10 compact digital camera for observing with the microscope. The camera has an AV output as do many digital cameras. This is connected to an Hauppage WinTV, TV capture card, S-Video/Composite input socket. I found the Hauppage card tricky to configure for this input and the capture software that came with the card played havoc with other hardware and software. I finally installed the card with drivers only and this worked.

I have the digital camera AV configured to NTSC (instead of PAL) as this gives the best match to the video capture setting of 640x480.

I use Virtualdub in Capture (File menu) mode for recording videos from the TV card. Once the device settings are correct Vdub should display the image output from the camera. On my setup I have to use Vdub's - Video/Preview setting to see the image.

Time-Lapse Method 1

The simplest method uses Vdub's Capture(menu) / Settings. Here the Frame Rate can be set. A value of:

0.1 will give 1 frame each 10 seconds (approx).
0.05 1 frame each 20 seconds
0.0166 1 frame each 60 seconds

The frame rate of recorded videos can be altered for playback using Vdub in edit mode -Video/FrameRate menu or a nice little programme called Frame Rate Adjust V.1.0 .

Time-Lapse Method 2

In some circumstances better results are achieved with very short clips recorded at intervals. Even just 0.5 seconds of video at 25fps can improve the visibility of tiny bacteria and convey a sense of its movement. To record such video a windows Macro or Hotkey programme is needed.

I have tried Hot Keyboard Pro ($30) which worked well but is a bit pricey for a simple job. I now use AutoHotKey which is free and has some very handy refinements, like being able to convert a script to an exe.

Set Vdub's Capture File where there is sufficient free disk space (File menu)
Set Vdub's Capture/Settings/Frame Rate set to 25fps (or whatever you choose - 25 matches my TV card)
Set Vdub's Capture/Stop Conditions/Capture time exceeds. (minumum 1 second)
Set Vdub's Capture/Stop Conditions/File Size exceeds: (minumum I found worked 3MB, this gives 13 frames or 0.5sec)

Use AutoHotKey to send F5 (Virtualdub/Capture AVI) at the desired intervals. The Vdub window must be active for the F5 to work.

Here is the script I use with AutoHotKey:

#Persistent
SetTimer,Capture,60000
return

Capture:
;IfWinNotActive, VirtualDub 1.6.15 - capture mode , , WinActivate, ;VirtualDub 1.6.15 - capture mode
Send, {F5}
Sleep, 1000
return

This is saved as an '.ahk' file type which will invoke AutoHotKey. The '60000' is the interval between sending F5 in milliseconds so it is 60 seconds. I disabled the window activate line as it is not required for my purpose.

With AutoHotKey running the duration between recorded clips can be varied by:

Right click the icon in the systray
Select 'Pause script'
Select 'Edit script'
Script opens in Wordpad
Change duration and save the script
Right click AutoHotKey systray icon and select 'Reload this script'

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