In today’s digital world, audio is stored and transmitted in digital format. Although digital audio can be transmitted without compression, uncompressed files are extremely large, requiring significant storage space and making transmission difficult. To make audio more convenient for streaming, broadcasting, and storage, developers have created audio codecs that significantly reduce file sizes while preserving the highest possible sound quality.
An audio codec uses a special compression algorithm to convert the original sound into a smaller digital file. During playback, the receiving device decodes the compressed data, reconstructing the audio signal so it can be heard through speakers or headphones. Over the years, many companies have developed their own audio codecs, each with its own balance of compression efficiency, sound quality, hardware requirements, and licensing model. As a result, several technologies have emerged as the most widely used. Among the most widely recognized audio codecs are Dolby, DTS, AAC, MP3, and WMA.
A codec’s popularity largely depends on its adoption by device manufacturers and content providers. The more widely it is supported on TVs, smartphones, computers, media players, streaming services, and other digital devices, the more it is used.
MP3 (MPEG Audio Layer III)
MP3 (MPEG Audio Layer III) is one of the most well-known lossy digital audio formats. Its development began in the late 1980s at the German research institute Fraunhofer IIS in collaboration with other participants in the MPEG project. The official standard was published in 1993 as part of the MPEG-1 specification and was later extended for MPEG-2.
The key feature of MP3 is its use of a psychoacoustic model, which removes sounds that are less perceptible to the human ear. This approach significantly reduces audio file size while maintaining acceptable sound quality.
By the late 1990s and early 2000s, MP3 had become the global standard for digital music storage. Today, it is supported by virtually all televisions, smartphones, car audio systems, media players, and computers.
WMA (Windows Media Audio)
WMA (Windows Media Audio) is a family of audio codecs developed by Microsoft. The format was introduced in 1999 as part of the Windows Media multimedia platform and was designed to compete with MP3.
Microsoft released several versions of the codec:
- WMA Standard — the primary lossy compression format.
- WMA Pro — an enhanced version with support for multichannel audio and higher sampling rates.
- WMA Lossless — a lossless audio format.
- WMA Voice — a version optimized for speech recording and voice communication.
In the early 2000s, WMA was widely used in Windows, portable media players, and several online music stores. However, with the growing adoption of AAC and the rise of music streaming services, WMA gradually declined in popularity. Despite this, many televisions, media players, and audio devices continue to support WMA playback to ensure compatibility with older audio collections.
AAC (Advanced audio coding)
AAC (Advanced Audio Coding) is a lossy digital audio codec developed in 1997 as the successor to MP3. It was created by an international group of companies and organizations that included Fraunhofer IIS, Dolby Laboratories, Sony, AT&T Bell Laboratories, and Nokia. The standard became part of the MPEG-2 family and was later incorporated into MPEG-4.
AAC provides higher audio quality than MP3 at the same bitrate thanks to more efficient compression algorithms. The codec supports sampling rates of up to 96 kHz, multichannel audio, and several profiles, including AAC-LC, HE-AAC, and HE-AAC v2.
Today, AAC is one of the most widely used audio formats. It is used by streaming services, digital television, YouTube, Apple Music, iTunes, and is supported on Apple and Android devices.
DTS audio codec
DTS (Digital Theater Systems) is a family of audio codecs developed by the American company Digital Theater Systems, Inc. (now part of Xperi). The format was introduced in 1993 and was originally designed for digital multichannel audio in movie theaters. One of the first films to use DTS was Jurassic Park (1993).
Unlike Dolby Digital, DTS used a higher bitrate, allowing it to preserve more audio detail. Over the years, several versions of the codec have been introduced, including DTS Digital Surround (5.1), DTS-ES, DTS 96/24, DTS-HD High Resolution Audio, DTS-HD Master Audio (a lossless format), and the object-based DTS:X format.
DTS is supported by many televisions, AV receivers, soundbars, Blu-ray players, and media players. However, in recent years, some TV manufacturers have stopped licensing DTS due to licensing costs, so support for this codec is no longer available in all TV models.
Dolby audio codec
Dolby Audio is a family of audio codecs and sound processing technologies developed by the American company Dolby Laboratories. The company was founded in 1965 by engineer Ray Dolby. These codecs have become the most widely used and are generally supported by virtually all devices capable of reproducing high-quality sound. To improve sound processing and reduce the load on processors, dedicated sound cards—which feature sound processors and codecs for decoding audio—are frequently used.
Dolby Digital (AC-3) was introduced in 1992 as Dolby’s first widely adopted digital multichannel audio codec. It uses lossy compression and supports up to 5.1 audio channels. Dolby Digital became the standard audio format for DVDs, digital television, and home theater systems, and it remains one of the most widely used surround sound formats.
Dolby Digital Plus was introduced in 2005 as an enhanced version of Dolby Digital. It provides more efficient compression, improved audio quality, and supports up to 15.1 audio channels. Today, it is the primary surround sound format used by streaming services and is commonly used to deliver Dolby Atmos audio.
Introduced in 2005, Dolby TrueHD is a lossless audio codec based on Meridian Lossless Packing (MLP) technology. It supports up to 8 channels (7.1) and delivers studio-quality audio identical to the original master recording. Dolby TrueHD is primarily used on Blu-ray Disc and Ultra HD Blu-ray.
Dolby Atmos was introduced in 2012 as a next-generation object-based surround sound technology. Instead of assigning sounds only to specific channels, Atmos treats sounds as individual audio objects that can be placed and moved anywhere within a three-dimensional space. It is widely used in movie theaters, home theater systems, televisions, soundbars, and streaming services.
Dolby AC-4 was introduced in 2014 for next-generation digital television and internet streaming. It offers more efficient compression than Dolby Digital Plus while supporting multichannel and object-based audio. Dolby AC-4 is used in modern broadcast standards, including ATSC 3.0 and DVB, and is designed to meet the requirements of current and future television services.
