People have different ways to compose and record music, soundtracks, melodies or sound effects. Even more variations come into play when arranging or artistically producing a song or a full album. For all types of audio productions, there comes a time when you finally need to mix all, independent recorded tracks down to one, two or more channels. The next step is to finish the formatting of the final mix and give it the last quality packaging by mastering the production. The audio production is now ready to be published, either electronically (broadcasting, download, streaming) or physically on a media support (CD, DVD, SACD, etc).
Therefore, at the start of each audio production, it is vitally important to have an idea how your next creation will be shared. The answer to this question will quickly define how you will practically record your production and what appropriate audio format you should consider.
Our modern digital age has brought myriads of audio file formats and, at some point, you must have asked yourself; what is the best audio format for highest sound quality, what should be used for streaming on the web, what are the audio differences between the various social media and streaming platforms? With internet bandwidth increasing, there is less needs to compress audio files as much as before, but everyone who is involved with making music and audio production is all too aware of the compromised nature of the sound quality of some compressed audio file formats. Let’s explore this.
Audio Codec: What do you mean?
An audio codec is a device or a computer program. In a computer, an audio codec may be a computer program implementing an algorithm that compresses and decompresses audio information according to a given sound record or streaming media-sound coding format.
A codec comprises both the digital-to-analog converter (DAC) and the analog-to-digital converter (ADC) and manages both converters at the same time. MP3, Windows Media Audio (WMA) or Dolby Advanced are examples of prevalent codecs. They work like a hardware circuit that changes sound waves into advanced code and vice versa. The term may apply to only the A/D and D/A signal transformation, or it may include the compression procedure to assist decreasing or modifying the signal.
Loss and Compression
There are three basic types of codecs, which either include file size compression, or not. Let’s detail how such different algorithms work.
- Uncompressed Format: it defines a sound record that has no compression connected to it. The uncompressed sound remains identical to when it was recorded.
- Lossless Compression Format: it is an information compression calculation that allows the compression and decompression of sound records without any compromises to the perceived audio quality. Lossless compression means that as the file size is compressed, the audio quality remains the same whilst the file size itself can be reduced by up to 50% without losing quality.
- Lossy Compression Format: it is an information calculation that disposes of less important information within the sound record to create a data package that is less demanding to transmit. Lossy compression codecs make use of psychoacoustic principles to achieve their significantly smaller sizes. With the human hearing apparatus (ears/brain) and due to the psychoacoustic phenomenon of ‘masking’, some elements of a sound record are covered up by others and the listener does not perceive them. Lossy algorithms break down and analyze audio waves, and encode the bits that represent these masked portions of the audio at lower bit resolutions. Such algorithms use ‘perceptual coding’ to perform the psychoacoustic analysis and data reduction, and the resulting audio files can have their sizes reduced by up to around ten times. However, such data/size reduction comes at a cost. Unlike lossless files, lossy sound records do not preserve all the audio information and there is usually some audible loss of sound quality. How much sound quality is compromised, depends on the codec itself, its implementation and how small the new data-compressed audio file is.
Popular Audio Formats
DSD (Direct Stream Digital) – It is an amazingly high-resolution uncompressed audio format. DSD is much higher in quality than conventional 16 bit/44.1 kHz PCM data and lossless formats such as FLAC and ALAC. Due to its very high quality codec (using delta-sigma modulation, DSD data format is 1-bit/2.8224 MHz sampling rate), advanced audio converters are often required to play DSD records.
PCM (Pulse-Code Modulation) – it is an uncompressed audio format, representing digitally sampled analog signals. It is the standard form of digital audio in computers, CD, DVD, digital telephony and other digital audio applications. In a PCM record, the amplitude of the analog signal is sampled regularly at uniform intervals and each sample is quantized to the nearest value within a range of digital steps.
WAV (Waveform Audio Format) – WAV is another audio format that does not compress the original analog audio recording from which it is derived. WAV files offer a very high sampling rate and bit definition, which allows them to include the complete human ear spectrum. A WAV file encoder uses pulse code modulation (PCM) data format. They are difficult to stream since their uncompressed shapes implies they are expansive recordings.
BWF (Broadcast Wave Format) – Based on the WAV audio format, BWF is also an uncompressed format dedicated to audio data, to which the EBU (European Broadcasting Union) has added ‘broadcast audio extension’. It can be used for the seamless exchange of audio material between different broadcast environments and between equipment based on different computer platforms.
AIFF (Audio Interchange File Format) – AIFF is an audio format that is totally uncompressed and can be played on both Macs and PCs. Made by Apple it is indistinguishable from PCM format sounds. Due to its large records, streaming in AIFF is conceivable but not commonly utilized.
FLAC (Free Lossless Audio Codec) – FLAC is a lossless, open source audio format, featuring a very efficient compression algorithm, which can reduce the file by 50-70% over its original size. This format is popular among audiophiles as a way to store collections of music in their highest quality form. Because it is open source, this format is compatible with many devices and programs.
ALAC (Apple Lossless Audio Codec) – Sounding identical to a unique recorded sound, the ALAC codec, using the M4A file format, features lossless compression and allows for multiple edits without a loss of quality. Compared to other lossless formats, M4A files have a similar quality but are lower in file size and essentially play on Apple devices.
MP3 (Moving Picture Experts Group Layer-3 Audio) – It is one of the most well known sound codec. MP3 records use lossy compression, which definitely compacts audio. MP3 records can be ten times smaller than WAV records. MP3 files can be encoded at either constant or variable bit rate. A constant bit rate ensures the same quality throughout the audio file but results in higher file size. Variable bit rate detracts from quality during silent, or near-silent, moments in the recording, resulting in overall smaller file size.
WMA (Windows Media Audio) – WMA is available in lossy and lossless versions. Generally, WMA records are smaller than their uncompressed partners are, and comparable in usefulness to MP3s and FLAC records.
Ogg Vorbis – it is an open-source, patent-free, lossy audio format that is excellent for streaming over the web without compromising speed. Providing good sound at low bit rates, it compresses audio and disposes of information to achieve smaller record sizes. Also, OGA/OGG files tend to be higher in quality than MP3s.
AAC (Advanced Audio Coding) – It is another lossy codec that provides small sound records and works extremely well for online streaming. They can also be created with either a variable or constant bit rate. AAC records are not adequate if you need a near-replica of the initial recording, since bits are discarded.
How to Choose?
Choosing the best audio format depends thoroughly upon the application and use. You ought to select an audio format that accomplishes the optimal sound quality for the publication, or transmission media, but nothing more. Superfluously high-quality audio recordings can be inconvenient to handle, edit and share.
- Professional audio engineers and audio content creators use uncompressed, high-resolution file formats to record, edit and master audio files, which maintain the complete sound quality. Once done with the final audio formatting, these records can easily be exported to easier-to-distribute compressed formats. PCM, WAV, BWF and AIFF are examples of uncompressed formats.
- If you are not an audiophile who wants to listen to your music collection in hi-fidelity, you can select a lossless audio format, which will use less storage capacity than an uncompressed format, holding still the complete quality of the initial recording. These formats include FLAC, WMA, and ALAC (M4A).
- If you need to share audio recordings or stream audio over the Internet, select a format that uses lossy sound compression. Fortunately, lossy compression codecs have improved their sound quality quickly in recent years, reducing significantly the difference between lossy and lossless compression. The MP3 format is probably the most popular one. MP3 files can be created in a variety of bit rates, which is used to balance sound quality versus size. Their efficient size has made them the standard format to exchange audio on the Web. Other common formats are Ogg Vorbis and AAC.
One more advice. When you need to export an audio mixdown to a final stereo mix, always make sure the audio file is optimized and of highest possible quality for the destination media (CD, DVD, broadcasting, Web streaming, etc).
Audio on the Internet
With the plethora of social media platforms, the possibilities to share audio productions over the internet is immense. Touching this topic raises the following question: what audio format should I use when uploading my production on the internet? Like most things in the social media world, audio and video specifications tend to change often. Most changes are related to media platforms improving their solutions to deliver more pleasurable viewing and listening experiences for their users.
If all of these changes are challenging to keep up with, the table below provides a summary of today’s state of affairs.
|Audio Formats 1||Video Formats 1|
|Stereo AAC codec at 128 kbps+||.MOV and .MP4 with H.240 compression codec|
|Stereo AAC codec at 128 kbps+||.MP4 or .MOV with H.240 compression codec|
|Mono or stereo AAC-LC|
|.MP4 for web, .MOV for mobile|
|Snapchat||Stereo PCM or AAC codec,|
min. 192 kbps, 16 or 24 bit only,
48 kHz sample rate
|.MP4 or MOV, with H.264 compression codec|
|YouTube||Stereo MP3 (in MP3/WAV container), PCM (in WAV container), AAC (in MOV container), FLAC audio.|
Minimum audio bitrate for lossy formats: 64 kbps
|.MOV, .MPEG4, MP4, .AVI, .WMV, .MPEGPS, .FLV, .3GPP or .WebM|
|AAC or MPEG4 codec,|
lower than 64 kbps
|.ASF, .AVI, .FLV, .MOV, .MPEG-1, .MPEG-4, .MKV or .WebM|
|Vimeo||Stereo AAC-LC (Low Complexity),|
320 kbps, 48 kHz sample rate
|H.240, Apple ProRes 422 (HQ), H.265 (HEVC) codecs|
|Audio Formats 2|
|Spotify||Accepts stereo FLAC or WAV. All files are converted to WAV (44.1 kHz) and transcoded into one of the following:|
Ogg/Vorbis (96, 160 or 320 kbps) – AAC (128 or 256 kbps) – HE-AACv2 (24 kbps)
|Pandora Premium||AAC+ (32 kbps or 64 kbps) MP3 (192 kbps)|
|Apple Music||AAC (256 kbps)|
|SoundCloud||Supports WAV, FLAC, AIFF, ALAC, MP3, AAC, Ogg / Vorbis, MP4, MP2, M4A, 3GP, 3G2, MJ2, AMR and WMA Recommends using WAV (16 and 24 bits), FLAC, AIFF or ALAC|
|TIDAL HiFi||Master Quality – Partnership with MQA (Master Quality Authenticated) delivering audio masters from 44.1 kHz / 16 bits, to 96 kHz / 24 bits (in some cases 192 kHz) between 2304 and 9216 kbps|
HiFi – FLAC (44.1 kHz / 16 bits) at 1411 kbps
Standard – AAC (320 kbps)
TouchMix Mixers and Audio Formats
With the above overview of common audio file formats, you may wonder how do QSC TouchMix mixers handle their audio recording capabilities. All TouchMix models are capable of recording all their inputs, plus a stereo mixdown, directly to an external USB drive, without any computer required. Tracks are created in uncompressed 32-bit Broadcast Wave Format (BWF) and can be played back and mixed down on the mixer or imported into a Digital Audio Workstation (DAW) software for over-dubs and post-production editing work.
Additionally, a free TouchMix DAW Utility for both Windows and macOS is available to help move TouchMix tracks to DAW software and vice versa.
Despite the ever-increasing internet bandwidth, and besides purely technical considerations, lossy audio files have become the standard for generations of music-lovers and music-makers who grew up with them. This should not stop new generations to be exposed, to enjoy and acknowledge the superior sound quality of uncompressed audio formats.
For all of us concerned with high sound quality, we should continue to actively share uncompressed and lossless audio whenever possible, find the highest-quality codecs, choose highest bitrates and keep an eye on the technology developments in this area. Striving for best audio reproduction is not sufficient if high quality audio formats are not broadly used.
Technical data taken from each respective streaming media platform.