Download and install a program that can convert a movie file into an audio file. Many programs can convert files to multiple formats such as movie files in MP4, AVI, WMV, MOV, movies coming from a DVD, or audio files in WAV and MP3.
Popular freeware programs such as AoA Audio Extractor and DVD Audio Ripper are readily available for online download. Other conversion programs that you can buy include DVD To WMV Converter, AudioExtract and SWF to MP3 Converter.
Go to the "Add Files" menu in your conversion software. From the window that appears on screen, look for the movie file intended for conversion. Once it is located, select the file, then click "Open."
Choose the audio format you want for your destination file. For a program that can convert to multiple file formats, select the "Audio" option or go directly to the option for the specific audio format such as "MP3" or "WAV." The available button selections depend on the software used.
Some conversion programs can only convert to one specific audio format such as MP3 or WAV. In such cases, instead of selecting the "Audio" format, you may have to directly press the "Convert" button or any other button referring to the file conversion.
Configure where you want to save the output file, whether in the computer's internal hard drive or an external hard drive connected to the computer.
Press the "Convert" button or any other button that confirms the file conversion. The button name depends on the software used.