Dolby Digital 5.1 Surround Sound (AC3)

5.1 Surround Sound for Home Theaters, TV Broadcasts, and Cinemas

Dolby® Digital (AC-3) is an industry-standard surround sound audio codec designed to deliver 5.1 channels of audio to many popular forms of entertainment including DVDs; Blu-ray Discs; cable, broadcast, and satellite TV programming; PCs; and even video games. An advanced encoding/decoding technology, Dolby Digital reproduces multichannel audio to deliver a cinematic audio experience.

See Dolby Digital Plus to learn about the latest surround sound audio codec.

As the established standard for home theater, broadcast, and cinema surround sound worldwide, Dolby Digital provides rich, enveloping sound that adds impact and realism both at the movies and in your home theater. In fact, every DVD as well as all HD broadcasts in the United States use Dolby Digital.

Dolby Digital Benefits

A worldwide standard in surround sound, compatible with millions of existing systems

Enables up to 5.1-channel surround sound for an enveloping audio experience

Compatible with devices featuring Dolby Digital Plus 

Next-generation devices and new entertainment mediums have resulted in the evolution of Dolby Digital technology to enable increased efficiencies and scalability. The result is Dolby Digital Plus, a refined and enhanced form of Dolby Digital.

Are you a Dolby licensee or looking for more technical details? Learn more about Dolby Digital.

Dolby Digital Plus

Dolby Digital Plus provides all of the core functionality of Dolby Digital while adding new features that are critical to today’s content delivery mediums such as HDTV and online streaming, as well as devices such as tablets and smartphones.

Dolby Digital Plus decoders are designed to be playback compatible with your existing Dolby Digital media.

How Dolby Digital Works

Audio is turned into digital information through a process called encoding. The specific form of digital audio coding that Dolby uses is referred to as “perceptual coding.” Using Dolby’s unique expertise in how humans actually perceive sound, our technologies are able to determine what parts of the audio track are important to keep and what parts audiences are less likely to hear.

Dolby Digital Multichannel Surround Sound

By retaining the important parts of the audio track and identifying redundant data, Dolby Digital can deliver great multichannel surround sound at lower data rates.

This very efficient form of high-quality data compression enables multichannel audio to be delivered by broadcast, distributed on DVD, or downloaded online at data rates considerably less than those of two-channel PCM audio.

Dolby Digital 5.1 Audio Playback

The data is then decoded for playback. Metadata created during programming production and carried in the Dolby Digital bitstream enables mixers and artists to offer additional features so you have more control over your playback experience. It also ensures you get a high-quality audio experience, whether you’re listening on a mono, stereo, or 5.1-channel system.

Dolby Digital Technical Features

Surround sound delivery at lower bit rates for broadcast networks and DVDs and higher bit rates for Blu-ray Discs. (See also Dolby Digital Plus.)

Metadata that describes content and in effect informs your system how the audio should play back in terms of loudness, dynamics, and number of channels. 

Sophisticated encoding and decoding technology for clear, multichannel sound.

Automatic stereo downmix for two-channel systems to ensure content is playback compatible with a wide variety of devices.

Products with Dolby Digital

Cinema
Computers
Digital televisions
DVD and Blu-ray Disc players 
Game consoles
Gaming headsets
Home theater systems
PC software
Set-top boxes (cable/DBS)

Featured Products

To help give you an idea of what's out there, we feature a number of select products from our partners. You’ll find Dolby Digital in many more products than we can show here.

(Our product listings aren’t meant as specific recommendations or ratings.)

Astro A40 gaming headset
JVC TH-BA3 wireless home theater system
The Witcher 2 game  
Oppo BDP-95 Blu-ray Disc player 
Xbox 360® Elite 

Dolby Digital 5.1 Content

DVDs
HDTV broadcasts
Blu-ray Discs 

Dolby Digital Specifications

Channels: 1.0 to 5.1, discrete

Data rate: 32–640 kbps, scalable

DVD data rate, 5.1-channel audio: 384 or 448 kbps

Blu-ray Disc data rate, 5.1-channel audio: 640 kbps

Supports Dolby metadata: Yes

Connections: S/PDIF, HDMI®, IEEE 1394

Mixing/streaming capabilities: Yes

Compare Dolby Digital Features

Dolby Digital is one of several Dolby technologies that deliver surround sound. Although we’ve engineered each for specific applications, all Dolby technologies are designed for optimum playback compatibility. Whatever Dolby technology is in your media or components, you still experience the best sounding audio possible for your system.

Feature	Dolby Digital	Dolby Digital Plus	Competing Technologies
7.1 channels		•
5.1 channels	•	•	•
Streaming/download support	•	•	•
Multichannel BonusView™ support for Blu-ray™		•	•
Dynamic range compression	•	•
Automatic stereo downmix	•	•	•
Support for mobile networks		•
Scalable for bandwidth-constrained applications		•
Lossy compression	•	•	•
Data rates supported: mono–multichannel	32–640 kbps	32 kbps– 6 Mbps	384–1060 kbps