AC3 – Definition

AC3 standing for Audio Coding 3, is a file extension for surround sound audio files. It is created by Dolby Laboratories in 1987 for use on DVDs, Blu-ray players, HDTV programming and home entertainment systems. AC3 format contains up to 6 discrete sound channels. The most frequently used 5 channels are dedicated for normal-range speakers (20 to 20,000Hz) and 1 channel for low frequency (20 to 120Hz) subwoofer effect. Specifically, they are left front, right front, center, left rear, right rear and 1 ultra-low track called 5.1 channel which is the standard surround sound audio most commonly used in commercial cinemas and home theaters.

Filename Extension: AC3

Category: Audio File

Popularity: Popular among home theater enthusiasts

Developer: Dolby Laboratories

Facts about AC3

  • AC3 can operate sound frequency under 20 to 20,000Hz which equivalants to human’s audible hearing frequency. This means AC3 can produce unique, detailed and diverse sound effect for people.
  • Most HDTV programming today takes AC3 as the standard audio format. Coupled with HD signal television broadcasting, it makes everything lifelike most especially the sound.
  • Formerly, it is not AC3 but Dolby Pro Logic 4.0 adopted as the company’s standard format. Dolby Pro Logic 4.0 can be found on many VHS tapes released on the 1980s.
  • The bitrate of AC3 audio on DVDs is up to 640kbps and sample rate up to 48kHz.

Pros: AC3 is accepted as the industry standard for DVD media and DTV. Nearly all DVD movie soundtracks take place in AC3 format. AC3 is highly compressed and it is small in file size, but the sound effect is faithfully preserved as the original DVD. AC3 can be converted to videos file types like AVI and MPEG, which can achieve 5.1 Dolby Digital Surround sound as well when we play them on media players.

Cons: AC3 is widely used on DVDs and very seldom used and appeared in other respects. Though AC3 supports 7.1 channels, when it comes to audio CDs, it only supports a maximum of 5.1 channels and limit to 448kbps.


AAC or Advanced Audio Coding is very much different from AC3. AAC is a type of lossy digital audio format which is promoted as the successor of MP3 because it generally achieves better sound quality within the same file size. AAC format is a more advanced lossy format than AC3 format. It will create better audio sound quality than AC3 with same bitrate, especially at low bitrate. Below is a more in-depth comparison between AC3 and AAC.


  • AC3 was developed by Dolby Laboratories and it was originally named Dolby Stereo Digital until 1994. This format has been taken as the international standard by Moving Picture Experts Group since 1997.
  • AAC was developed with the cooperation of AT&T Bell Laboratories, Dolby Laboratories, Sony Cooperation, Nokia and Fraunhofer IIS. In 1997, Moving Picture Experts Group declared AAC an international standard.


  • AC3 file format is a 6-channel surround sound which provides a total bitrate of 384 kilobits per second and it supports audio sample rates up to 48 kHz. You must use an amplified theater system that supports Dolby Digital to reproduce the full effect of AC3 track.
  • AAC can store a large amount of audio info using little space. It is a more advanced lossy audio format than AC3. Its sample frequency ranges from 8 to 96 kHz so the sound quality is better than AC3 when the audio file is encoded at low bitrates.


  • AC3 is widely used as the standard sound track of DVDs, Blu-ray, HDTV programming and game consoles.
  • Apple adopted AAC as the default format for its iTunes and iPod since 2003. A majority of devices and players support AAC format. Many in-dash car audio systems adopt AAC.

Programs that can play AC3 files

VLC Media Player – VLC media player is made by VideoLAN project. It is an all-around media player running on multiple platforms including Windows, Mac, Linux, Unix, iOS and Android that supports all audio and video formats.

KMPlayer – Full name is K-Multimedia Player. It is a media player available on Windows OS. It can play a large number file types including AC3 format. KMPlayer was auquired by Pandora TV (a Korean streaming video company) in August, 2007.

Nero Multimedia Suite – Nero AG developed this software suite for Microsoft Windows. This software suite includs Nero Burning ROM for disc authoring and copying, Nero Video for video editing and creating of video discs, Nero RescueAgent for data rescue and many other free applications.

Xine – Developed by the Xine Project, Xine is a multimedia playback engine for Unix-like OS. It features a great ability of manually correcting the sync of audio and video streams.

ALLPlayer – ALLPlayer is a Polish freeware media player famous for the ability to read the matching subtitles during the playback of movies. ALLPlayer also has an integrated Equalizer with many sound presets ( pop, rock, techno music, etc )which gives a cinema-like audio effect.

Complete-set of Solutions for AC3 file


Convert AAC to AC3 – AAC is a common audio format mainly used in MP4 and MKV format container. Many media players are able to play the MP4/MKV files which contain AAC audio track. If you wish to enjoy MP4 or MKV movies with cinema-like audio effects right at the comfort of your home, you’ll have to convert the audio file from AAC to AC3.


Convert DTS to AC3 – DTS(Digital Theater System) and AC3 (Dolby Digital) are two mainstream audio codecs used in cinema and home theater system for playback of multi-channel high-definition audio. In reality, DTS was adopted in DVD later than AC3 and not all players can play files in this format. AC3 is the standard audio format for DVDs. To make DTS audio accessible for all DVD players, we need to convert DTS to AC3.

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