Introduction to Audio Codecs and Containers

Audio codecs and containers are necessary to deliver high-quality sound and images to our devices. The unnoticed behind the crystal-clear audio in our favorite podcasts, movies, and music are audio codecs, even though video codecs frequently get all the attention.

We will delve into the realm of audio codecs and containers in this thorough examination, paying special attention to Vorbis, Opus, FLAC, Speex, and ALAC.

Audio & Video Encoding Process
Audio & Video Encoding Process | Source

What are Audio Codecs?

Audio codecs are the digital algorithms responsible for compressing and decompressing audio data. They are designed to strike a balance between data size and audio quality, making it possible to store and transmit audio efficiently.

Types of Audio Codecs

How Do Audio Codecs Work?

Audio codecs function by eliminating redundancy and unnecessary data from the audio signal. They employ various strategies to achieve compression. Through these techniques, audio codecs identify and discard audio information that the human ear is less likely to notice.

The difference in frequency between a compressed MP3 and uncompressed audio
The difference in frequency between a compressed MP3 and uncompressed audio | Source
  • MP3 (MPEG-1 Audio Layer 3): A widely used lossy audio codec that compresses audio data, significantly reducing file sizes. Example: MP3 codec is used to compress audio data within an MP3 container.
  • AAC (Advanced Audio Coding): Another lossy codec, often associated with higher audio quality at lower bitrates. Example: AAC codec can be used within M4A and MP4 containers.
  • FLAC (Free Lossless Audio Codec): A lossless audio codec that doesn't lose any audio quality during compression. Example: FLAC codec is used within a FLAC container.
  • ALAC (Apple Lossless Audio Codec): A lossless codec developed by Apple, often used in their ecosystem for lossless audio compression. Example: ALAC codec is used within M4A (Apple's container) for lossless audio storage.
  • SPEEX: An open-source container designed for voice compression, frequently used in VoIP applications.
  • AC3, or Audio Codec 3: An audio data compression technology developed by Dolby Laboratories. It can encode multiple audio channel formats into a single low-rate bitstream.
  • Vorbis: A free and open-source software project that creates an audio coding format for lossy audio compression. Often used with OGG container and referred to as OGG Vorbis format
  • Opus: A versatile audio codec that can handle a wide range of interactive audio applications. It was developed in 2012 by the IETF working group.

What is Vorbis Audio Codec?

A free and open-source audio technology developed by the Xiph.Org Foundation, Vorbis is frequently used alongside the Ogg container. With a heavy emphasis on maintaining audio quality while lowering file size, it was created to be a superior replacement for MP3. The reason Vorbis is so well-known is that it can reduce the size of audio recordings without compromising on quality.

Its ability to modify the degree of audio compression in response to sound complexity is one of its primary features. It implies that you can still obtain high-quality music at reduced compression levels. Due to its open-source nature and lack of licensing fees, Vorbis is widely favored by music aficionados and streaming services.

What is Opus audio Codec?

Xiph.Org has developed a unique audio technology called Opus. Your audio will sound great even if your connection is sluggish because of its exceptional ability to adjust to various internet conditions. Opus has the cool feature of being incredibly speedy and not making you wait long to hear stuff. It's excellent for real-time communication because of this.

Opus is great for things like phone conversations, online gaming, and live streaming when speed is crucial because it can reduce sound files without sacrificing quality and adjust the quality based on your internet connection.

What is FLAC Audio Codec?

For audio quality, FLAC, or Free Lossless Audio Codec, is like a superhero. FLAC preserves audio quality without compromising it, unlike Vorbis and Opus, which reduce the size of audio files but do so at the expense of some quality loss. The fact that FLAC effectively reduces audio files without sacrificing any audible quality is what sets it apart from other formats.

A lot of people use it to store and safeguard their music libraries. To ensure that your audio quality remains at the highest level, FLAC is the recommended format, regardless of whether you're converting your vinyl recordings into digital files or preserving a live concert recording for future generations.

What is Speex Audio Codec?

Speex is an audio compression codec specifically tuned for the reproduction of human speech and also a free software speech codec that may be used on voice over IP applications and podcasts. It is based on the code excited linear prediction speech coding algorithm. Its creators claim Speex to be free of any patent restrictions and it is licensed under the revised (3-clause) BSD license. It may be used with the Oggcontainer format or directly transmitted over UDP/RTP. It may also be used with the FLV container format

What is ALAC Audio Codec?

ALAC stands for Apple Lossless Audio Codec. It is an audio codec developed by Apple Inc. for the lossless compression of digital audio.

Key features of ALAC:

  • Lossless Compression: ALAC uses lossless compression, which means that audio files compressed with this codec can be decompressed to their original, bit-for-bit identical form without any loss of audio quality.
  • File Extension: ALAC-encoded audio files typically have file extensions like .m4a (when stored in an MPEG-4 container) or .caf (Core Audio Format), which are common on Apple platforms.
  • Open Source: In 2011, Apple made ALAC open-source, allowing it to be used in various non-Apple software and hardware applications.

What is an Audio Container?

Audio containers, also known as audio file formats, serve as the digital equivalent of a physical container—a vessel designed to hold and organize audio data.

These formats encompass audio files, providing a structure and means to store, transport, and manage audio content efficiently. Essentially, audio containers act as wrappers for audio data, bringing order to the chaos of raw audio information.

One of the most popular music and video multimedia containers is the Ogg container, which usually comes with the Vorbis and Theora codecs.

Audio Containers
Audio Containers

  • WAV (Waveform Audio File Format): A container format often used for uncompressed or lossless audio data storage.
  • MP3 (MPEG-1 Audio Layer 3): While MP3 is often used to describe both the codec and the container, it's important to note that MP3 files are typically contained within formats like WAV or the more specialized MP3 file format (e.g., .mp3).
  • FLAC (Free Lossless Audio Codec): A container format that holds lossless audio data, encoded using the FLAC codec.
  • M4A (MPEG-4 Audio): An audio container format used for various audio codecs, including AAC and ALAC, providing flexibility within the same container.
  • AIFF (Audio Interchange File Format): An audio container for storing lossless audio data, often used in professional audio production.
  • OGG (Ogg Vorbis): An open-source audio container that may contain audio data compressed using the Vorbis codec.
Popular Audio Containers
Popular Audio Containers

What is Ogg Audio Container?

The Ogg container format is an open multimedia container that is flexible and supports a wide range of codecs. It was created by the Xiph.Org Foundation.While Ogg can contain both audio and video, we'll primarily focus on its role as a carrier for audio codecs like Vorbis and Theora.

a. Vorbis in Ogg: As mentioned earlier, Vorbis is a widely used audio codec, and when paired with the Ogg container, it creates an open and efficient solution for audio streaming and storage. This combination offers high-quality audio at smaller file sizes, making it a preferred choice for online music platforms and podcasts.

b. Theora in Ogg: In the realm of video, Theora is the star of the Ogg container.  When packed into an Ogg container, Theora delivers impressive video quality while maintaining compatibility with open standards. It has been used for various web video applications, although it faces competition from more modern codecs like VP9 and AV1.

Advantages and Disadvantages of Ogg Container Format:

  • Open Source: Ogg is open source and free to use, making it an attractive choice for developers and content creators.
  • Codec Flexibility: Ogg can contain a variety of audio and video codecs, allowing content creators to choose the codec that best suits their needs.
  • Efficient Compression: Ogg's compression is efficient, providing smaller file sizes without a significant loss of quality.
  • Streaming-Friendly: Ogg is commonly used for streaming audio and video content on the internet, thanks to its efficient compression and wide codec support.

Drawbacks of OGG Container:

  • Limited Adoption: Ogg's adoption is not as widespread as other container formats like MP4 or AVI.
  • Video Codec Competition: While Theora is a capable video codec, it faces competition from more advanced codecs like VP9 and AV1, which are preferred for online video streaming.

What is AIFF Audio Container?

High-quality, uncompressed audio data is typically stored in AIFF, or Audio Interchange File Format, an audio container format. It was developed by Apple and is commonly associated with their ecosystem, although it is widely supported on various platforms. Here's an overview of AIFF, including its advantages and drawbacks:

Advantages of AIFF Audio Container:

Uncompressed Audio: AIFF is a lossless audio container, which means it stores audio data without any compression. This results in audio files that maintain the highest possible quality. This makes AIFF a popular choice for archiving original audio recordings, ensuring that the audio remains pristine over time.

Wide Compatibility: AIFF is supported by various audio software and hardware, making it a versatile format that can be used on both Mac and Windows platforms.

Metadata Support: AIFF files can include embedded metadata, allowing users to store information about the audio content, such as artist, album, and track details.

Lossless Compression Option: While AIFF is typically uncompressed, there is an option to use lossless compression with AIFF-C (Audio Interchange File Format-Compressed). This allows for some space savings without any loss of audio quality.

Drawbacks of AIFF of Audio Container:

Large File Sizes: The main drawback of AIFF is its large file sizes. Since it stores audio data without compression, AIFF files can be significantly larger than other formats, which may not be suitable for online distribution or storage with limited space.

Not Ideal for Streaming: AIFF files are not optimized for streaming due to their large size. Smaller, compressed formats like MP3 or AAC are preferred for online streaming platforms.

Less Efficient Storage: AIFF's lack of compression efficiency means it requires more storage space compared to compressed formats like MP3 or FLAC.

Limited Use in Certain Environments: While AIFF is a preferred choice for professional audio production, it may not be the most practical format for everyday listening on portable devices due to its large file sizes.

What is M4A Audio Container?

M4A is an audio container format that is commonly associated with the MPEG-4 Part 14 multimedia container format. M4A files can contain audio data encoded with various audio codecs, the most common of which are AAC (Advanced Audio Coding) and ALAC (Apple Lossless Audio Codec).

Advantages of M4A:

High-Quality Audio: M4A files, when encoded with the AAC codec, provide high-quality audio, often indistinguishable from the original source. This makes them a preferred choice for music distribution and storage.

Efficient Compression: M4A files can be created with efficient compression algorithms like AAC, which reduces file sizes without significant loss of audio quality. This is especially important for portable devices with limited storage.

Versatility: M4A containers support a wide range of audio codecs, offering flexibility in choosing the codec that suits your specific needs, whether it's lossless audio with ALAC or efficient compression with AAC.

Metadata Support: M4A files can store metadata such as artist names, album titles, track details, and cover art. This makes them ideal for organizing and categorizing audio content.

Apple Ecosystem Compatibility: M4A is the default audio format in Apple's ecosystem, ensuring compatibility with Apple devices, software like iTunes, and platforms such as Apple Music.

Drawbacks of M4A:

Limited Support on Non-Apple Devices: While M4A files are versatile, they may not be as universally supported on non-Apple devices and software, potentially causing compatibility issues.

Not Ideal for Lossless Enthusiasts: If you are an audiophile who demands the highest audio quality and prefers lossless formats, M4A may not be your first choice. While it supports ALAC, there are other dedicated lossless formats like FLAC that might better suit your needs.

File Size Considerations: If you're seeking the smallest possible file sizes for online distribution or storage, M4A files with the AAC codec might not be as compact as other more aggressive lossy codecs like MP3.

Frequently Asked Questions (FAQs) About Audio Codecs and Containers

Q1. What are codecs and containers?

Answer- The main difference is that the codec is the actual software that does the compressing of your video file, while the container is the package the final project is delivered in for playback.

Q2. What is the difference between an audio codec and a container?

Answer- The Codec encodes and compresses, then decodes and decompresses the data that makes up your video. It is about what comes out of the camera; the filming and recording process. The Format or Container stores the audio, video, subtitles, and other elements that make up your video.

Q3. Is AAC a codec or container?

Answer- The AAC extension is short for “Advanced Audio Coding”, which is a standard audio container format for compressed digital audio and music data.

Q4. What does audio codec do?

Answer- In software, an audio codec is a computer program implementing an algorithm that compresses and decompresses digital audio data according to a given audio file or streaming media audio coding format.

Q5. Is MP4 a container or codec?

Answer- MP4 is a popular container today, as it supports several of the most-used codecs and is broadly supported. The original MPEG-4 Part 1 file format was introduced in 1999; the version 2 format, defined in Part 14, was added in 2003.

Q6. What is the full form of codec?

Answer- codec, an abbreviation of coder-decoder or compression-decompression, is a standard used for compressing and decompressing digital media, especially audio and video, which have traditionally consumed significant bandwidth.

Q7.What is an AVI file?

Answer- Audio Video Interleave, known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback. (AVI icon)

Q8 What is the most common codec?

Answer- H.264 also known as AVC (Advanced Video Coding), is the most common video codec; AAC (Advanced Audio Coding) is the most common audio codec.

Q9 What is the highest-quality audio format?

Answer- WAV (Waveform Audio File) retains all the original data, which makes it the ideal format for sound engineers. “WAV has greater dynamic range and greater bit depth,” creative producer and sound mixer.

Q10. What is the simplest audio codec?

Answer- Wave files are the simplest sound format. They have a header (which can sometimes be complicated but usually isn't), and then the actual sound data is raw, uncompressed PCM.

Q11. Which codec is better than AAC?

Answer- In brief, SBC is the most basic codec with the lowest bit rate and, therefore, the most basic sound quality. AAC and AptX are both steps up from SBC and are generally mainstream. AAC is the best you can do on Apple phones and tablets, while AptX is a step-up option on Android.

Q12 What is the best audio codec lossless?

Answer-Here are some of the best and most commonly used audio codecs on the market:

  1. MP3 (MPEG-2 Audio Layer 3) is likely the most famous audio codec out there.
  2. FLAC (Free Lossless Audio Codec) is one of the best free lossless audio codecs out there.
  3. AAC
  4. ALAC
  5. WAV
  6. AIFF
  7. WMA
  8. Ogg Vorbis or OGG File Format

Q13. Which is best AAC or FLAC?

Answer- FLAC is the superior audio format in general. Even though AAC can still produce high-quality audio, it lacks FLAC's level of information and clarity. But, Even if FLAC provides greater sound quality, the files are so large that they may not be suitable for streaming.

Q14. What is the maximum audio quality in AAC?

Answer- AAC is a more complex codec than SBC, meaning more power drain but also better sound quality. It can 'handle' 24-bit/44.1kHz audio files, with a bitrate of up to 320kbps, and is supported by Android devices (running Android 8 or later) as well as iOS.

Q15. What quality is audacity AAC?

Answer- The default setting is 256 kbps which is the quality that Apple now uses for audio files sold in iTunes/Apple Music. The Maximum bit rate (best quality) is 320 kbps (stereo) and 160 kbps (mono) and the minimum is 98 kbps (mono)

Q16 Is AAC audio or video? What is an AAC file?

Answer- The AAC extension is short for “Advanced Audio Coding”, which is a standard audio container format for compressed digital audio and music data. Improved in several aspects, this format produces better sound quality at the same bitrate compared to the older audio formats.