If you have a very large digital music collection, you might be struck by the number of digital formats your music comes in. Almost everyone knows of the MP3 format, but other formats like OGG, MQA, DSD, or AIFF seem very foreign.
Most of the time, the audio format your music comes in isn’t something you think about, as long as your media player can read them. In this article, we’re here to explain in-depth the meaning of common audio files and their importance.
Whether you’re listening to AAC tracks, low-quality mp3 files, or hi-res audio in WAV, it’s time to understand the best file format and what you’re getting from them. Let’s dive in.
What Is An Audio File Format?
An audio file format is a file format used for storing digital data on your computer system. Audio file formats are in two layouts: compressed and uncompressed. Audio file formats are compressed to reduce the file size also called lossy compression. Data in an audio file can be stored as bits but it is usually embedded in a container format with a storage layer.
Sample Rate and Bit Depth
You have likely noticed two values on your digital audio export settings: sample rate and bit depth. The sample rate is the number of samples an audio file carries per second while bit depth determines the amplitude resolution of audio files. These two values account for the differences between all audio file format types.
Sample rate and bit depth determine the frequency range, the dynamic range of the audio, and the resolution.
For a CD-quality audio, the standard sample rate is 44.1 kHZ and 16-bit bit depth. Anything below these values makes the audio not considered High resolution or high-definition ( HD). Most audio file formats we use have settings lower than what is qualified as High-resolution. The reason for this is as follows:
HD Streaming
Users who find downloading audio files stressful or want to reduce constraints to their computer resources consider streaming HD audio. There are a lot of streaming services that offer streaming in HD. Sites like Tidal, Amazon HD, and Qobuz and more recently Spotify will offer HD Streaming.. Although, HD streaming services offer a smaller music library compared to other non-HD streaming platforms.
Downloadable HD files
If you are enthusiastic about your music output, there’s an option to buy audio with a bit depth of 24-bit and sampling rate of up to 192kHZ. Although these purchases aren’t popular on music outlets, you can get 24-bit files on certain music outlets like
- Qobuz
- HD tracks
- Super HiRes
However, there is no demand for audio files with sample rates higher than 48Khz. Although some outlets offer higher quality they require a lot of storage space to acquire. Even content creators are not releasing audio file formats with sample rates higher than 44.1kHZ. That means that the highest quality audio files you can get will be between 40 to 44.1KHZ.
Main Groups of Audio File Formats
Audio file formats are classified into three main groups:
- Uncompressed audio format
- Lossy compressed audio format
- Lossless compressed audio format
Uncompressed Audio Format
Uncompressed file formats are in their original states- completely unaltered. They are 100% similar to the producers created in digital copies. They are created using pulse code modulation PCM. The same format is used to create DVDs and CDs.
For example if your master studio has 11001100110000 bits, the PCM track will contain the same amount of bits: 11001100110000 bits.
Uncompressed audio file formats are large, they take up a chunk of disk space. The most common uncompressed files are AIFF, PCM, AU, MWF, WAV, and BWF.
- AIFF ( Audio Interchange File format): Audio data in this format is in uncompressed PCM. This file format was developed by Apple.
- BWF ( Broadcast Wave Format): BWF is mostly used in the broadcast industry and allows large meta-data to be stored in the file.
- AU: This file format was developed by Sun Microsystems. It was used on their NeXT systems and when the internet was young.
- WAV (Waveform Audio file format): Developed by Microsoft and IBM. It consists of uncompressed audio and uses Pulse-code Modulation format (PCM).
- PCM ( Pulse-code Modulation): is the process used to convert analog audio into digital audio signals without compression. Compact-Disk (CD) brought PCM into consumer usage when it was first used in 1982.
As said earlier, uncompressed audio formats occupy a large space. However, the only suitable portable medium to carry such files are on discs such as DVDs, CD, and Blu-ray discs.
Lossy Compressed File formats
Lossy compressed file formats give smaller files compared to other audio format types. This is achieved by simplifying the data in the file and removing audio information as well. While the file size might be small, the audio quality is heavily impacted, depending on how far the compression goes.
MP3 is one of the popular file formats that is created along with ACC (Apple iTunes format) and Vorbis. It was created by Steve Jobs on 23rd October 2001. It is the most common audio format and is convenient for storing music on tablets, phones, portable players, and literally all playback devices.
The lossy compressed audio format uses psychoacoustic analysis. The advantage is that file size is reduced; however, the data lost cannot be retrieved and the file cannot be restored to its uncompressed original format.
Bitrate can be used to measure streaming of lossy compressed files, the unit used is kilobits per second.
Bitrate formula = Sample Rate and Bit depth x No. of Channels
The maximum bitrate for an MP3 file is 320kbps.
When the bitrate is at 320kbps and above, it is difficult to tell the difference between an uncompressed file and a lossy encoded file. The lower the bitrate, the more audio data lost, the crappier the audio quality.
Many streaming services such as Spotify and digital outlets use bitrates with a maximum of 320kbps. For casual listening, this sound quality is acceptable and goes unnoticeable most times.
Lossless Compressed Audio file
Lossless compression audio files are also compressed but no information is lost in the process. The original uncompressed audio data can be reformed back into the compressed version. Lossless compression is a way to reduce file sizes considering the fact that uncompressed files are very large.
All your audio data is stored and the audio quality is not affected in any way. With lossless compression, you get the best out of your audio. Audio files are easier to store and distribute. And on playback, they can be decoded into the original state without degradation of any part of the original audio.
Lossless compression audio files work like a zip file. When you zip your documents, the file size is reduced making it compressed. When you ‘unzip’ the file, the original documents are brought back to life and nothing is altered.
How Lossless Compression Works
It seems like magic when you throw away data and you can recreate them to get back what you’ve thrown away. Unlike lossy compression, you can throw away data but are unable to recreate the original data.
Turns out with lossless compression, you can throw away data in a smart manner that allows the original to be recreated. This can be done by representing the data and identifying patterns in a shorter manner.
Here’s an example for how its done:
Bits for Great Track:
1100111000000010
A lossless encoder drops all the 0 and replaces it with another symbol that occupies a smaller space, thereby reducing the file size.
It can save the information as 11__111_______1_
When you decoder the above bits, the symbol used to replace 0 will be changed back to the original value- that is 0- to create the original bits.
There are various types of lossless compression formats, including ATRAC Advanced lossless, TTA, MPEG-4 SLS, MPEG-4 DST, MPEG-4 ALS, Shorten ( SHS), Windows Media Audio Lossless (WMA Lossless). However, the most common formats used are:
- Monkey Audio (filename extension ‘.ape’): This audio file format was created by Matthew T. Ashland, it works really well to compress files than other counterparts. However, it requires more processing power.
- FLAC ( Free Lossless Audio Codec) is an open format that supports album art cover and meta-tags. Audio data compressed with FLAC is reduced to 50 and 70 of its original price.
- ALAC ( Apple Lossless Audio Codec): ALAC uses filename extension ‘.m4a’. It was developed by Apple. It can also be called Apple Lossless or Apple Lossless Encoder ( ALE). It was initially a proprietary codec, but Apple made it available royalty-free and open source in 2011.
- WavPack: ( filename extension .wv), it’s also an open-source, and free audio compression file format created under the BSD license. Apart from being a lossless compression file, it creates files in two formats: a high-quality, lossy file (.wv) that can be used stand-alone and a ‘correction’ file. The correction file when combined with a lossy file provides a lossless restoration.
Lossless compression also allows you to archive audio files. Data isn’t lost in the process plus you achieve a file size reduction of up to 60%.
Different Audio File formats
WAV ( Uncompressed File format)
WAV stands for Waveform Audio. Developed by IBM and Microsoft in 1991, it was one of the first audio file formats created for laptops and computers. Files in this format have their extension as ‘.wav’ and they are often referred to as wave files.
WAV can be an anchor for both compressed and uncompressed files, but it is mostly used to anchor uncompressed PCM files, so they can be playable on Windows and MAC. It supports rates of up to 192khz and a bit depth of 32-bit. No additional processing or encoding is required because it’s in HD format. It is compatible with all hardware, software, and audio players that can decode digital files.
As we know, uncompressed formats have very large file sizes, so they take up a lot of storage space on your computer’s hard disk. They also take a long time to upload on the internet due to the large bandwidth.
Pros
- High signal quality
- Provides an accurate copy of the original recording
Cons
- Uses high bandwidth for internet uploads
- Large file size
AIFF (Uncompressed File Format)
AIFF stands for Audio Interchange File Format. This format was developed by Apple in 1988, around the same time the first iMac was developed. Like the WAV file, AIFF supports multiple types of audio, similar bit depths, sample rates, and number of channels. It comes in HD format and the file size is comparable. The audio quality of both WAV and AIFF is the same.
The difference between the AIFF and WAV formats is the different extensions. AIFF also has better support for metadata tags. When you enter additional data like a genre in an audio player software, the data gets added to the file immediately. This is not the case for WAV files.
Pros
- High signal quality
- Exact copy of the original data
- Supports meta tags to store additional data
Cons
- Occupies large space due to large file size
- Required high bandwidth for internet uploads
ALAC (Lossless Compressed file format)
ALAC stands for Apple Lossless Audio Codec. Also developed by Apple, it was launched in 2004 but made free for use in 2011. ALAC uses lossless compression and unlike other formats, its extension is not its name. It is presented by ‘.m4a’. It’s part of iTunes and Quicktime.
When ALAC files are compressed, they retain up to 60% of the size of the original file. When played, they are uncompressed and sound like the original audio. It is supported by most software media players on PC and MAC.
For hardware support, only a few iOS devices, FiiO devices, and iRiver are allowed. You can upload ALAC files on Google Play Music and Tidal. However, they will be converted to MP3 for streaming. Google Play Music converts ALAC files into 320kbps.mp3 files during streaming.
Lossless files use more internet bandwidth to stream, however, the advantage it has over lossy formats is the preservation of the audio quality.
Pros
- Small file size
- Better than uncompressed files
Cons
- Limited Mobile Player Support
FLAC (Lossless Compression File Formats)
FLAC stands for Free Lossless Audio Codec. It is open source. ALAC file format is a bit similar to FLAC, but when compared FLAC can decode and stream faster than ALAC. However, this is not really noticeable when gaming or watching film sync. In these situations, little latency is needed. Latency is a short delay when an audio signal enters a system and when it emerges.
There are 9 different levels to FLAC compression, it starts from 0 to 8. The higher the level, the slower the encoding speed and the higher the compression ratio.
But there is one downside to using FLAC which is its incompatibility with Apple products. Therefore, if you’re a MAC or PC person, ALAC and FLAC should be really considered when choosing the best audio file format for use.
Pros
- Small file size
- Open-source
- Sound comparable to uncompressed files
Cons
- Doesn’t support Apple products
MP3
MP3 stands for MPEG-1 Audio Layer 3, it is one of the most popular compressed file formats. After its introduction in 1993, it became very popular due to its small file size suitable for fast distribution on the internet.
MP3 is created in an uncompressed format, such as AIFF or WAV, then processed with an encoder. The resolution and quality of the music you hear are based on the bitrate set in the encoder. The highest resolution an MP3 file can produce is 320kbps. Paid Subscriptions of streaming services offer music audio in 320kbps. Free services can go as low as 128kbps. The advantage of MP3 files is the small file size and its compatibility with almost all media players.
AAC ( Advanced Audio Coding)
Like MP3, AAC uses lossy compression. It was developed by Bell, Sony, Nokia, LG Electronics, Dolby. Fraunhofer, NTT Docomo, NEC and Panasonic. When encoding AAC at the same bitrate to MP3, AAC sounds better than MP3.
AAC started to gain more popularity after the invention of the iPods and the accompanying music library, iTunes. Both platforms support AAC out of the box. Apple Music allows streaming music using 256kbps AAC bitrate.
WMA ( Windows Media Audio)
It was created in 1999 as Microsoft’s response to MP3. It was created to improve on MP3 by sounding better at the same bitrate. WMA succeeded, however, it’s not as widely accepted as the MP3 and AAC.
It is not compatible with hardware and software as other formats. It is compatible with all Mac and Windows devices. Even though WMA sounds better than MP3 and AAC, the latter is so popular that suppliers and users default to using them.
OGG
OGG is another format created to improve on MP3. This file format is free for both commercial and non-commercial use. It’s also a popular streaming format but like WMA, it hasn’t been widely accepted by MP3 and AAC.
Spotify is one of the streaming platforms that allow OGG as its default audio file format. The standard quality for the desktop app is OGG vorbis 169 kbit/s. Premium subscribers can also switch to high-quality streaming at 320kbit/s. OGG is the smallest audio file format. But is not compatible with most devices and software, that is why users go for MP3 when picking an audio file format.
Conclusion
Different Audio file formats have their uses, strengths, and weaknesses. When music is a major part of your life, you always want to listen to high-quality music. Now that you understand the different audio formats and how they work, you can choose which one works best for you and what results to expect.
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