Software & Apps File Types What Is an AC3 File? How to open, edit, & convert AC3 files by Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated on June 24, 2020 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email A file with the AC3 file extension is an Audio Codec 3 file. Much like the MP3 format, this one uses lossy compression to reduce the overall size of the file. It was created by Dolby Laboratories and is often the sound format used in movie theaters, video games, and DVDs. AC3 audio files are designed to support surround sound. They have separate tracks for each of the six speakers in a surround sound setup. Five of the speakers are dedicated to a normal range and one speaker is dedicated to low-frequency subwoofer output. This corresponds to the configuration of 5:1 surround sound setups. How to Open an AC3 File AC3 files can be opened with VLC, QuickTime, Windows Media Player, MPlayer, and other multi-format media players, such as CyberLink PowerDVD. If you find that an application on your PC tries to open the file but it's the wrong application, or you'd rather have another installed program open it, you can designate a different default program for AC3 files. How to Convert an AC3 File Several free audio converters support converting AC3 files to other audio formats such as MP3, AAC, WAV, M4A, and M4R. Zamzar and FileZigZag work in your web browser to convert the file. Just upload it to one of the websites, choose an output format, and then save the converted file to your computer. Still Can't Open the File? If you've tried opening it with the programs mentioned above but it's still not working, re-read the file extension. It's easy to confuse another file for this one if the file extensions are similar, which is pretty common. For example, A3D files might look related to this format but those are actually Alternativa Player 3D Export files that don't contain any audio data. AC (Autoconf Script) is another. Although it's missing just the number at the end, the format itself is completely unrelated and has nothing to do with AC3 files. Some other files you might misread as this one include AAC and ACO.