You can edit video files using the software supplied with your camera or with your operating system or buy something or use free open source software. What free open source software is out there in regular use and working across popular operating systems?
Linux real time
When you edit sound and video in real time, Linux has significant internal delays that cause dropouts. Dropouts can occur any time you convert analogue sound or video to digital, including converting old video tapes to digital. Dropouts occur in most operating systems when used on slow hardware or with several applications running at the same time. Linux has a particularly bad problem in the standard Linux.
There is a real time version of Linux designed to work with real time audio and it might work with real time video on a fast computer. The best current version of Linux is Ubuntu and there is a real time version of Ubuntu named Ubuntu Studio at ubuntustudio.org. You install Ubuntu Studio instead of regular Ubuntu then install all your regular applications.
There are downloads to install most of Ubuntu Studio over an existing installation of Ubuntu but you may not get the critical real time version of Linux.
Free open source
Avidemux is available for Linux, Mac OS X, and Windows. Download Avidemux from http://avidemux.sourceforge.net. Avidemux uses a QT interface in Windows and either QT or GTK in Linux. Your version might look different from the screen shots at the Avidemux Web site.
Avidemux can create FLV files for use in Flash and could be used instead of the Articulate Video Encoder and similar programs. If you use Articulate and the Video Encoder is supplied free, you would probably use the supplied one because the user interface is the same. When you start editing videos for other uses, you want a video editor that will produce more formats and work across more computers without extra cost or complicated licensing. Avidemux works well for multipurpose editing.
Avidemux has simple editing features. A professional video editor making significant money from commercial videos would buy one or more of the commercial tools with additional features for use in specific situations.
Avidemux converts file to file and is not upset by the lack of real time support in standard Linux or any other operating system. You might have a problem if you use the bulk conversion facilities of Avidemux to convert from an analogue source.
Generally you copy from analogue to digital without any fancy conversion and without any other application active. No Web browsing. No email. No virus checking. No automated backups. After you produce the digital file, you can run any sort of format conversion including CPU intensive conversions, without dropouts.
Avidemux does not use Java, which reduces the processing overheads and makes editing practical on older computers and notebooks.
There are many input formats supported. There are fewer output formats because some of the input formats are proprietary. The output format list contains all the important formats.
Kino, from www.kinodv.org does some things you would not do in Avidemux but Kino works only in Linux. Kino is installed as part of Ubuntu Studio. If you only use Linux, use Kino.
The Kino Web site is painfully technical and is oriented to recording from cameras. If the video from the camera is analogue, you need the real time version of Linux which means you install Ubuntu Studio instead of just dropping Kino on top of standard Linux.
Modern cameras record digital to SD cards then you insert the SD card into your computer and edit digital to digital, which removes the need for real time and some of the special features of Kino.
Blender is used more for video enhancement than editing. Download Blender from www.blender.org.
Blender is supplied with Kino in Ubuntu Studio. Blender is available for Windows and can be used on files created by Avidemux.
I mention Blender because the combination of Blender with Kino gives you many more features than Kino alone and may be enough to cover everything provided by Cinelerra. Blender also provides 3D animation, something you might use for fancy titles.
Cinefx is a rewrite of an older project named Jahshaka. Download Cinefx from www.cinefx.org. They also have a video player named CinePlay and a video to Flash converter named CineCode. All the products run on Linux, OS X, and Windows.
Cinelerra, from heroinewarrior.com/cinelerra.php, is open source but proprietary. There is a free open source version community developed version at cinelerra.org. Think of Cinelerra as Kino with a thousand extra processing options.
I do not know how the current community edition compares to the current commercial version. They are developed in parallel and both editions may have new features not in the other edition. Neither edition is in Ubuntu Studio.
Lives, from lives.sourceforge.net, is for real time editing of video during live performances. You can split Lives into a video server and a separate client for remote control. You could set up a performance through a video server and sit at a little netbook making the occasional change.
VirtualDub, from www.virtualdub.org, is available only for Windows and I have not found anything in VirtualDub that is not in Avidemux. If you use both applications and know of an advantage of VirtualDub over the current Avidemux then add a comment to this page.
Supplied with Windows
Microsoft Movie Maker is a good start for people using a recent version of Windows, except Vista, and has just one real problem, you do not know what it does internally because nobody can read the code in Microsoft Movie Maker to check what happens inside. Microsoft Movie Maker is Unknown Inside™.
Start with Avidemux then experiment with Blender. If you are totally dedicated to Linux, install Ubuntu Studio and use Kino then Blender.