P1 Technology Helpdesk
with John Rivera
P1 Tech Help: Decoding the mystery of video codecs
There are plenty of different types of surveillance video cameras, and they produce different types of data files
You are called to a convenience store to take a report of a theft. The reporting person says they have video and gives you a CD copy of the surveillance video. You proudly take the CD to your department to write your report and view the video and find the CD only contains unassociated files and cannot view the video.
A file extension tells your computer (and you, if you are curious), what kind of file it is. For instance, when you view an MS Word document file it might look like “PoliceOnearticle.doc” with the extension “.doc” telling the computer that once the file is selected, it will open it with MS Word. This selection can be changed and I will explain in a later article.
An unassociated file means that your particular computer does not have the software and cannot open that file. It shows up as with a generic icon and once you select it, a pop up will open and notifies you with a comment that it cannot open the file without the particular software.
In patrol, we sometimes do not have the time to find the software to open the file and view the contents of the file. I’ve been fortunate enough to get a video CD, find a codec and view the file or video in Windows Media Player.
A “codec” is a program that can compress or decompress the video or audio file. A codec is usually needed to view videos or listen to music in programs like Windows Media Player. Windows Media Player has many codecs already within the program, but there are too many types of video programs available to have all possible codecs already contained in your media player.
There just too many different viewers used and we cannot assume that one establishment will use the same viewer software as the other. I will focus on Windows Media Player because most agencies write their reports on the Windows platform and the Windows Media Player is already embedded in that platform. If you find yourself in the situation I described above, update your Media Player.
Open Media Player with the CD still inside the player (this way the program will automatically look for the particular codec it needs), select “Help” and select check for updates. Hopefully the programs will automatically find the right codec and download it.
If that does not work, try to do a Google search for the extension. For instance, if the file extension shows “.leo” Google “extension .leo” and see what comes back. You may or may not find it. Most surveillance video software is proprietary and the software is not readily available.
Searching for the codecs and extensions can be a headache depending on the severity of the crime and the desire of promptly identifying the suspect or witness. One way to be sure you can view the video in the CD is to ensure the reporting person giving you the CD with the video downloads the viewer onto the CD as well.
As some of you may already know, many of the downloaded viewers have the capability of magnifying an area of the still and printing the still shot.
You may be asking yourself about “.flv” files that are so prevalent on the Internet. Well, “.flv” files are Flash Video files. These files are associated with Adobe software and need Adobe reader software to view online videos.
The easiest way to avoid the headache of trying to view unassociated video files is to double check the CD, do what I mentioned above, and ensure the surveillance video player is on the CD as well.
Good luck, and stay safe.