How can you trim repeating/consistent video from a video?

Question

A friend is working on a sleep study for their university. As part of the study, they place night-vision camcorders in children's rooms and have to monitor how often they wake up, call out for their caregiver, etc.

Right now, they are forced to watch 8-12 hours of video, most of which can be ignored since the child is sleeping most of the time. They'd like to have software do much of the menial work for them.

Does anyone know of any software that can strip out the "boring"/consistent parts where the child is sleeping and only mark pieces of video that are different than the rest of the video?

Answer 1

What they want is a video recorder that works with motion detection. Many security systems only record when there is movement in the video frame. There are also web cam applications that double as security systems that use motion detection to start recording.

WebCam Monitor is just one example of an application that does what you need.

Answer 2

This is a sleep study lab, but they don't have any automated tools? OK, let's say this is a low-budget operation for some good reason.

Identifying the location of key frames (where activity ramps up, or frame-to-frame dissimiliarity spikes) is a common feature of many kinds of video editing or visualization software.

Here are a few ideas for things you could strap up cheaply to get what you need for key frame detection or motion detection:

• Here's a course in Fundamentals of Multimedia Computing where students wrote a perl script to use a similarity measure to identify key frames in MPEG files. (Maybe you can get the authors to share.) Output seems to include key frames and timestamp graphs.
• You could write a time-domain filter to highlight pixel level changes (recolor darker pixels redder, lighter pixels greener); big movements will throw up easily-observable color fringes around whatever is moving; while you're doing that, output a graph of your frame-to-frame similarity measure.
• Get some surveillance software; here's a Windows example: digi-watcher; here's a Linux example: ZoneMinder.
• You could look for a non-linear video editor for which importing your video will give you some visualization that will help identify important moments in motion.