Build ffplay and ffmpeg 2.6.2 on Mac OSX 10.10.2

Every few years we need ffmpeg and ffplay for some little job. The ffmpeg suite is my go-to swiss-army knife for whipping video into shape. Unfortunately, the compilation process is challenging. Here is a summary of the recipe I used to build these tools on OSX 10.10.2. It was not exactly straightforward. That’s why I wrote it down.

To jump to the end, the most difficult part was getting SDL-1 to build. (https://www.libsdl.org) I tried using SDL-2 with ffplay, but that combination did not compile correctly. ffplay requires SDL-1, and SDL-1 required some manual edits to get it installed.

Continue reading Build ffplay and ffmpeg 2.6.2 on Mac OSX 10.10.2

Video Summarization is the Biggest Problem with Internet Cameras

What happens when you record every frame emitted by an IP-camera? You end up with too much data to make sense of. I now have nearly unlimited data storage, but have little interest in reviewing everything stored. Watching recorded footage in real-time is too time-consuming to be enjoyable, or even reasonable. While playing it back at 2x or 4x speed might sound like a good idea, that’s still a lot of video to look at.

Please Summarize!

Most video editing software offers a “scrubbing” operation for rapidly finding a point in time. Scrubbing is the act of manually moving the transport control backwards and forwards through the images. If you’ve ever scrubbed looking for a single frame you remember seeing, you’ll have noticed that it’s sometimes hard to find the frame. Your monitor is displaying no more than 60 or 75 frames per second: if you scrub over a time period with a resulting rate faster than this, you are not seeing everything.

“Video summarization” is a field of study aimed at developing algorithms and methods to help abstract and identify interesting features in a segment of video to help direct viewer’s attention. Here is a great quote describing video summarization [ 1 ].

Video summarization methods attempt to abstract the main occurrences, scenes, or objects in a clip in order to provide an easily interpreted synopsis.

At Sensr.net, we consider video summarization to be an important part of our technology, recognizing that keeping a collection of all the frames your camera emits is just too much data to use. Our summarization techniques are straightfoward: we use motion-detection algorithms and save only those frames. We also offer a simple form of “hierarchical video-summarization.” When you look at a shot of all of the hours-of-the-day you are presented with the most important 24 frames of that day. Similarly, the days-of-the-month are summarized by the most important frame of each day.

Sensr.net has been hard at work laying the “pipes” for moving the frames emitted by internet cameras through our processors and into the cloud. You can expect to see more from us in the video summarization arena. Until then, take a look at this excellent slide presentation and think about what sorts of summarization you would like to see for your internet camera application.

[1] http://www.cs.utexas.edu/~grauman/courses/spring2008/slides/Video_Summarization.pdf

Benign Surveillance – a Friendly Eye

What if you could look at any public place, anywhere in the world, from your home.  What if there was a network of shared cameras, available for your use.  Would you look at a scenic vista over San Carlos?  Would you see who is arriving at Ritual Coffee in the Mission?  Would you look to see if the sun was shining out at Lands End?

What would you call the activity that you’re doing?

  • Is it surveillance?
  • Is it peeping?
  • It is watching?
  • Are you a voyeur?

None of these words describe very well the benign use of internet cameras to take a look at something somewhere else.  Sensr.net provides such a service and our tag line is simply “Watch your Stuff!”  I think this is a pretty good summary of what people are currently doing with Sensr.net.  They’re also doing things like sharing their camera views and posting clips to Twitter and Facebook.

Often, when I’m talking to people about Sensr.net and internet cameras, I receive a partially hostile response.  People associate cameras with centralized authority or control.  Even the word “surveillance” implies watching someone because they are suspect [http://dictionary.reference.com/browse/surveillance].  People worry about their privacy.  The meme that makes us worry about being watched seems pretty deeply ingrained in our society.  I’ve wondered where that comes from.

Watching has long been used as a form of control.  In the 18th century, a philosopher named Jeremy Bentham designed a type of prison called the Panopticon.  The word combines the roots for “observer” (-opticon) with “all” (pan-).  In this prison, an observer could see everyone no matter where they were.  The idea was that if no one knew when they were being watched or when they weren’t all prisoners would behave.  Closed-Circuit Television (CCTV) is sometimes considered a modern incarnation of the Panopticon.  But in at least some studies it’s been shown that all this watching doesn’t really cut crime rates [http://arstechnica.com/tech-policy/news/2008/05/problems-with-the-panopticon-uks-cctv-doesnt-cut-crime.ars].

So what happens when remote cameras simply become an adjunct to the other ways we perceive our environment?  Then internet cameras simply become tools for viewing.  One of my co-founders noted that perhaps the feeling of invasion stems from the fact that there are two different groups of people: the watchers and the watched.

With Sensr.net we have an opportunity of turning things around, contrary to traditional video surveillance.  With Sensr.net, the watchers and the watched can be part of the same social network. [YB 2010]

I really like this idea, but then I come back to the problem that generated this blog post: what is a good word to describe the service that Sensr.net is providing?  I don’t have one yet, so I might have to invent my own.  How about a word with Latin roots: “amicus-oculus” – a friendly eye!  Not very sexy, but not scary either.

If you’re reading this and you have a good suggestion for a word or phrase we can use to describe Sensr.net, please contribute it below as a comment.

Embed your DCS-920 in your Web-page or Blog

To the right of this article, you can see a streaming view of the DCS-920 from my house.  This capability is enable by a new service from Sensr.net.  The viewer is called a “widget” and can be plugged into any web-site or blog.

Viewer widgets can be created for any cameras that you own.  First, add your DCS-920 to Sensr.net (shown here http://www.tsheffler.com/blog/?p=187).  Then, select the “My Widgets” item from the pull-down menu.  This will show you the HTML embed codes for the widget.

Sensr Widgets

The rest is easy.  Copy the HTML and paste it into your blog like I did here.