All about file formats and codecs
Audio file formats are different forms of compression, all differing in quality the listener will experience on the receiving end. Programs used to process audio files are called audio codecs which compress audio for transmitting data and decompress it when the data is received.
The speed of audio codecs is measured in bitrate (kbps), or thousands of bits processed per second—this number can vary even within the same audio format. Typically, the lower the bitrate, the smaller the audio file. It can come at the cost of more data lost in compression, affecting the sound quality.
Other factors when it comes to audio formats include bit depth and sample rate. The latter is the number of samples—sound, or the signal amplitude—per second. The bit depth is the number of bits per sample. The higher the bit depth, the fuller or louder the sound will be.
Understanding who your listeners are and where they will listen is important when choosing the right file format. You want to have your audience be able to access your audio fairly easily while balancing the quality of the sound.
Compressed vs. uncompressed: Understanding audio file formats
Each audio format is either compressed or uncompressed. Uncompressed audio, which includes WAV, AIFF, and DSD file types, means the data remains the same size from the transmission to the receiving end. Compressed audio means that portions of data are taken out of the recording to make it smaller and easier to store or share. Compressed audio is broken down into two different formats.
- Lossless audio formats. These files will ensure the sound quality is intact because it decompresses files back to their original size. They’re usually much larger compared to lossy formats. File types include M4A, MQA, WMA, FLAC and ALAC.
- Lossy audio formats. Data will be lost in the transmission with lossy audio formats. Once the audio is compressed, it won’t decompress back to the original size. Some quality may be lost, or degraded, but the files tend to be smaller. File types include MP3, AAC, and Ogg Vorbis (OGG)
10 common audio file formats
The exact format you choose will depend on what your needs are and what tradeoffs you’re willing to make. Here’s a closer look at each audio file format:
- AAC. Short for Advanced Audio Coding, the AAC format is similar to the popular MP3 and is generally better for streaming over mobile devices. Android devices, Apple Music and Youtube tend to use this format.
- AIFF. The Audio Interchange File Format was created by Apple and is similar to the more well-known WAV file. AIFF retains all of the original data and tends to be a larger file size. AIFF files don’t have time codes so they aren’t necessarily useful for mixing and editing. You can play AIFF files on Macs and PCs.
- ALAC. This format is Apple’s Lossless Audio Codec (similar to FLAC) and only works on Apple devices. This format is used in iTunes and for Apple’s music player.
- DSD. The Direct Stream Digital is a high-quality single-bit format—hence larger file sizes. They’re usually found on Super Audio CDs and played on high-end audio systems and not appropriate for streaming.
- FLAC. The Free Lossless Audio Codec is an uncompressed, royalty-free codec that also stores metadata. Most use the format to download and store high-resolution audio files.
- M4A. M4A audio format correlates with MPEG-4 video files, generally found on Apple devices. They have smaller file sizes and the audio quality is comparable to MP3s.
- MP3. MP3 is a popular lossy compression audio format that offers small file sizes but at the cost of potentially poor sound quality. It’s a popular choice for streaming online and storing files on mobile devices.
- MQA. MQA is used for Tidal Masters hi-resolution streaming, this specialized file format helps make for more efficient streaming.
- OGG. Ogg Vorbis is similar to MP3s and AACs, and is an open-source codec. Spotify uses this in their streaming services, where they stream at 160kbps for the free version and 320kbps for the paid version.
- WAV. WAV is an uncompressed file format that offers great sound quality and is used for encoding audio on CDs. It doesn't store a lot of metadata and often has huge file sizes.
How to choose the right audio file format?
Choosing the right format depends on what you are using your audio for. In most cases, you’ll want to choose the most popular audio formats, especially if you want your files to be as accessible as possible. Plus, some formats aren’t supported by popular audio editing programs, so keep that in mind if you’re not someone who has specialized editing equipment.
You want to choose an audio format that helps you achieve the kind of audio quality required. Don’t worry about getting super high-quality audio files if you don’t require it because large files are cumbersome to convert, manage, and share.
Here are a few scenarios to help you determine between file formats:
- Uncompressed formats. You’re an audio professional who is planning on editing files such as ones for a podcast. Choosing either AIFF, PCM, or WAV allows you to export a file that has high-quality audio and is easy to distribute.
- Lossless formats. You’re an audiophile who wants to listen to high fidelity or the best audio quality for music. WMA, M4A, and FLAC files allow you to keep the data in the original recording but don’t require as much storage space.
- Lossy formats. You’re someone who wants to ensure your audio files are shared easily online or who wants to save disk space. Using AAC, OGG, or MP3 formats will result in some loss in audio quality, but you’re not someone who can tell the difference, nor will others with whom you share it.
Audio format FAQs
What is the best audio format for sound quality?
The best audio formats for sound quality are uncompressed or lossless compression files—think WAV, FLAC, and M4A. That’s because these formats retain the original sound quality, though you’ll have to put up with the fact these files will be large.
What audio file format is best for use on the web?
The best audio file formats to use on the web are MP3s and MP4s. They’re most likely to be compatible with most web browsers such as Google Chrome and Firefox. Other formats that most browsers support include AAC, OGG, and WAV, though they tend to have large file sizes.
What is the most popular audio format?
The most popular audio formats are MP3s. It is one of the easiest file types to download and share, and it doesn’t take up too much disk space compared to other file formats.
In addition, you can create MP3s with different bitrates which can alter your file’s size and quality. Due to its flexibility, many devices play MP3 files making it one of the main ways to share audio online.