Windows: Ever download a movie from — oh, I don't know — some far-reaching nether-region of the internet, and when your download finishes, realise the video is split into multiple parts? AVI Joiner quickly combines those split videos in just a few clicks.
Using it could not be easier. Just run the app (AVI Joiner.exe), drag and drop the files you want to join into the Files to be joined pane, make sure they're in the correct order, and click the Run AVI Joiner button. The app will ask you where you want to save the joined video (name it and make sure to add the .avi extension to the end), then sit back as it fires up a command line and starts the joining process. I joined a couple of 700MB files into a 1.4GB video in roughly a minute.
This awesome little app was built courtesy of the Lifehacker Coders group over at the Productive Geek forums. You can currently grab the download hosted over at drop.io here. (For a portable version, grab the AVI_Joiner.zip file; if you want an installer, grab the setup.exe and install.nsi files. Make sure you grab the newest versions, and if we happen to hit a bandwidth cap at drop.io, be sure to let me know.)
AVI Joiner is a free, open-source application for Windows only.
Let's do a simple AHK project together: AVI joiner [Productive Geek]