CLamCam Video

Timelapse Calculator App

TIMELAPSE CALCULATOR USAGE

The timelapse calculator allows one to quickly compute unknown parameters needed to collect video or sequences of still images to create timelapse videos.

There are four key parameters involved in timelapse activities:

  • Event Duration, the total time of the event for which you want to create a timelapse video,
  • Clip Length, the desired length of the video clip that portrays the Event,
  • Frames per Interval, the number of images collected at each frame interval, and
  • Frame Interval, the time period between the collection of frames during the Event.

Normally, one knows the first three and needs to determine the fourth. However, if one is using a video camera with "interval recording" then the Frame Interval will usually be a discrete, but changeable value so that it may be desired to get the exact Clip Length resulting from a given frame interval. Also, tape-based video cameras usually must take more than one frame per interval so that parameter is settable within Timelapse Calculator.

Another factor involved is the frame rate of the subsequent video playback. In the USA this is normally 30 frames per second (for normal video) or 24 frames per second for film-like playback. In Europe and many other countries of the world the video frame is 25 frames per second. All three of these values are selectable within Timelapse Calculator. Newer camcorders may now have a 60 (NTSC) or 50 (PAL) frame per second mode. Timelapse Calculator provides for these frames rates also.

DIFFERENCES BETWEEN VIDEO AND STILL CAMERA TIMELAPSE

STILL CAMERAS

Using a still camera for timelapse is relatively straightforward. Just set up the camera to take a picture at each Frame Interval and then integrate the series of still pictures into a video clip. Besides the camera, two things are needed: a device to trigger the camera at each frame interval (and "intervalometer") and a software program to create a video clip from the series of still images. A web search on "intervalometer" will turn up several candidates. Some still cameras have a built-in intervalometer. A similar search on "timelapse creation software" will reveal several candidates. Mac users can use QuickTime Pro to create video clips from sequences of still images.

An advantage of using a still camera to create the timelapse video clips is the inherently higher resolution than most video cameras.

VIDEO CAMERAS

Many current video cameras have an "interval recording" mode in which the camera automatically collects one or more frames at each Frame Interval. Once collected, the series of frames can be played back by the camera without any further processing. There is one proviso - if the camera creates more than one frame per Frame Interval then the resultant playback will be somewhat jerky. (See TIPS below)

In fact, all tape-based video cameras with an interval recording mode usually must take more than one frame per interval. The Timelapse Calculator allows one to set the number of frames collected per Frame Interval, up to 10. This assures one will know the exact length of the collected clip. The resulting clip length will be reduced if downsampling is performed as described in the previous paragraph.

TIPS

More than one Frame per Frame Interval can result is jerkiness in the final video. Thus, if the camcorder being used collects mulitple frames per Frame Interval one must post-process the video with video editing software to down-sample the video by factor equal to the number of frames collected per Frame Interval.

In general the factors that are selected first are Event Duration and Clip Length. Entering these two first permits calculation of the Frame Interval required.

DETERMINING FRAMES COLLECTED AND FLASH CARD CAPACITY

You can use the calculator below to determine the number of frames required to create a resultant video clip of a desired length and the frame capacity for a flash card given a frame size. Just enter the time of the clip you want and click on the button and the number of frames required for the three video playback rates will be displayed. Likewise, enter the size of the image frames you are collecting, click on the button and the number of those frames that can be recorded on the three different size flash cards shown will be calculated.

Enter Clip Length (secs): NUMBER OF FRAMES REQUIRED
(for these playback rates)
24 fps:
25 fps:
30 fps:
Enter Frame Size (MBs): FLASH CARD CAPACITY (frames)
(for this card size)
  8 GB:
16 GB:
32 GB:

RELATED LINKS

How timelapse photography works.

A timelapse photography tutorial.

Timescapes.org.

Vimeo timelapse forum.

More timelapse tutorials.

© 2008 CLamCam Video.
All Rights Reserved.