Avidemux is a free video editor and encoder that supports several file types, outputting video to AVI, MPEGs for authoring to DVD or VCD, MPEG-4, MKV and FLV (Flash Video). Converting multiple files in Avidemux (also known as batch processing) requires creating a ".bat" file in a text writing program and running the "Command Prompt" in Windows, which establishes a direct connection between you and your computer's operating system and bypasses the Microsoft Windows interface. Note that this process only works for converting a series of videos in the same format to a different format. You will not have all the capabilities of Avidemux's default graphical user interface (GUI).
Open a new Windows Explorer screen and create a new folder on your computer's main hard drive (usually your "C:" drive). Note the title of your folder.
Open a second Windows Explorer screen and locate the video files you want converted. (All files being converted need to be in the same format). Drag and drop their icons into your newly created folder. Leave this window open.
Visit the "Command Line Usage" page at Avidemux.com to check the list of "arguments" (or protocols) for the various commands you may want to use when converting your video. (For example, you may want to convert to MP4 with a specific frame size or audio or video codec).
Open a text or writing program on your Windows computer and copy the following text example to use a template for a basic conversion. Note this example is for converting .mp4 video to .avi (Xvid+MP3 encoding). set avidemux="C:\Program Files\Avidemux 2.5\avidemux2.exe" set videocodec=Xvid set audiocodec=MP3 for %%f in (*.mp4) do %avidemux% --video-codec %videocodec% --audio-codec %audiocodec% --force-alt-h264 --load "%%f" --save "%%f.avi" --quit (The last two lines should be in one line of text).
Change the "C:\Program Files\Avidemux 2.5\avidemux2.exe" line if Avidemux is located somewhere other than your "C:" drive or if you are using a different version than Avidemux 2.5. Change the "videocodec=Xvid" to "videocodec=" followed by the desired codec. Change the "audiocodec=MP3" to "audiocodec=" followed by the desired codec, if needed.
Change the "(*.mp4)" if the videos you want converted are in a different format. Change the ".avi" in the "--save "%%f.avi" line to reflect the desired file type you want converted to.
Save your text file as "something.bat," where the ".bat" is your file extension. (You can replace "something" with any word). If asked by Windows if you want to save your text file as a ".bat," click "Yes."
Locate your ".bat" file in Windows Explorer. Drag and drop its icon into the same folder as the videos you want converted. Double-click the ".bat" file to begin the batch conversion.
The "arguments" (or protocols) are "evaluated" from left to right and processed one at a time.
This article is for Windows users running the standard "Win32" operating system. Other operating systems have different command lines and file name limits; so this article will not work for you.