What Is an Audio Codec?

Blog 6 min read | Nov 10, 2023 | Martina Georgievska


In our digitally interconnected world, audio codecs quietly shape our auditory experiences. But what exactly are audio codecs, and why are they essential? This article delves into the realm of audio codecs, elucidating their importance and how they impact our daily interactions with sound.

Whether you’re a music enthusiast, a video conferencing user, or someone who values high-quality audio, grasping the concept of audio codecs is a crucial step in unraveling the intricacies of digital sound.

Let’s dive in!

What is an audio codec?

An audio codec is a hardware or software component used to compress or decompress audio data. Its main purpose is to reduce the size of audio files while maintaining a decent sound quality.

Therefore, audio codecs make it possible to store and distribute audio more efficiently, which is crucial for activities such as streaming music or video conferencing.

The compression process removes excess audio data, resulting in a smaller file size. During the audio playback, the codec decompresses the data, restoring it to its original quality or a quality determined by the user.

Applications of audio codecs

Audio codecs are employed in a wide range of applications, including:

  • Music streaming: Services like Spotify, Apple Music, and Amazon Music rely on audio codecs to transmit music over the internet efficiently. This ensures that users can enjoy high-quality audio while minimizing data usage.
  • Video conferencing: Platforms such as Zoom and Microsoft Teams use audio codecs to deliver real-time audio during video calls, ensuring clear communication.
  • Mobile devices: Audio codecs are integrated into smartphones and portable media players to make the most of limited storage space without compromising on audio quality.
  • Voice assistants: Smart speakers and voice-activated devices use audio codecs to process and understand voice commands.
  • Gaming: In online gaming, low-latency audio codecs are crucial to provide a seamless experience and maintain effective communication among players.

What is lossy audio compression?

Lossy audio compression is designed to achieve a significant reduction in file size while sacrificing audio quality. These codecs employ sophisticated algorithms to analyze audio data and discard elements that are deemed less crucial to human perception. Therefore, this process introduces some level of data loss, which can manifest as a subtle loss in audio fidelity.

However, the degree of loss is often imperceptible to the average listener, allowing for efficient storage and transmission of audio content. Lossy codecs are widely used for music streaming, where optimizing bandwidth and storage space is essential, and the quality trade-off is generally acceptable to consumers.

What is lossless audio compression?

In contrast, lossless audio compression prioritizes the preservation of the original audio quality. When audio data is compressed using a lossless codec, the resulting file size reduction is achieved without any loss of audio information. This means that the audio can be restored to its original, pristine quality when played back, making lossless codecs ideal for situations where audio integrity is paramount.

Professional audio engineers often favor lossless codecs, as they ensure that every nuance of the original recording is retained. While lossless audio files tend to be larger, they are a crucial choice when uncompromised audio quality is the top priority.

A list of common audio codecs

Several audio codecs are in use today, each designed for specific applications. Here are some of the most common ones:

  1. MP3 (MPEG-1 Audio Layer III): MP3 is one of the most well-known audio codecs, often used for compressing music and audio files. It became popular for its ability to reduce file sizes significantly while maintaining reasonable audio quality.
  2. AAC (Advanced Audio Coding): AAC is another popular codec, known for its superior sound quality compared to MP3 at similar bit rates. It’s commonly used in platforms like iTunes and YouTube.
  3. Opus: Opus is an open-source audio codec designed for real-time applications such as internet telephony and video conferencing. It offers excellent sound quality and low latency.
  4. FLAC (Free Lossless Audio Codec): Unlike most audio codecs, FLAC is a lossless compression format, which means it retains the original audio quality while reducing file size. It’s a preferred choice for audiophiles who want the best audio fidelity.
  5. Ogg Vorbis: This open-source codec is often used for streaming and online gaming due to its efficient compression and quality.
  6. WAV (Waveform Audio File Format): WAV is a container format for audio data, often used for storing high-quality, uncompressed audio. While it’s not a codec in itself, it’s worth mentioning because it contains raw audio data.

What is the best audio codec for live streaming?

The choice of the best audio codec for streaming can depend on various factors, including your specific use case, target audience, and available bandwidth. Advanced Audio Coding (AAC) is a popular and widely used audio codec for streaming, and it’s known for its good balance between audio quality and compression efficiency. AAC is used by many streaming platforms and services, including Apple’s HLS (HTTP Live Streaming) and YouTube.

Here are a few reasons why AAC is often considered a good choice for streaming:

  • Audio Quality: AAC offers good audio quality, especially at higher bitrates. It provides better sound quality compared to older codecs like MP3, making it suitable for streaming music, podcasts, and other audio content.
  • Compression Efficiency: AAC can compress audio data efficiently, allowing for smaller file sizes while maintaining good audio quality. This is important for streaming, as it reduces the amount of bandwidth required to transmit audio content.
  • Compatibility: AAC is widely supported across different platforms and devices, including iOS devices, Android devices, web browsers, and various media players. This ensures that your audio streams can reach a broad audience.
  • Adaptive Streaming: AAC is commonly used in adaptive streaming technologies like Apple’s HLS and MPEG-DASH, allowing for adaptive bitrate streaming. This means that the codec can adjust the quality of the audio stream in real-time based on the viewer’s available bandwidth, ensuring a smoother streaming experience.

However, the choice of codec also depends on factors like licensing, platform-specific requirements, and the specific needs of your audience. Different streaming platforms and services may have their preferred codecs, and in some cases, you may need to use multiple codecs to ensure compatibility.

For live streaming, it’s also important to consider the bitrate at which you encode your audio, as higher bitrates typically result in better audio quality but require more bandwidth. You should strike a balance between audio quality and bandwidth requirements based on your audience’s internet connection capabilities.


Audio codecs are essential components of the digital audio ecosystem, allowing us to enjoy high-quality audio content while efficiently managing file sizes for storage and transmission. Whether you’re streaming music, video conferencing, or simply listening to your favorite tunes on a portable device, audio codecs silently work behind the scenes to enhance your audio experience. Understanding these technologies empowers users to make informed choices about audio quality and storage efficiency in various digital media applications.