Uncompressed audio files are digital representations of soundwave, which are most accurate. However, it can be a resource-intensive method of recording and storing digital audio, in terms of storage and management. They are generally the master audio formats of choice as they are suitable for archiving and delivering audio at high resolution due to their accuracy. They are also suitable when working with audio at a professional level.
PCM is the major uncompressed audio format that is stored as a .wav on Windows or as .aiff on Macintosh operating systems. The aforementioned formats are flexible file formats designed for the storage of any combination of sampling rates or bitrates. The AIFF format is based on the IFF format, and the WAV format on the RIFF file format that is similar to the IFF format. These formats are working formats within many audio, video and multi-media applications, and Digital Audio Workstations employed for professional audio production and editing.
The listed uncompressed audio file types are ‘wrapper’ formats that use PCM audio and add additional data to enable compatibility with specific codecs and operating systems. Although some of them were developed for specific platforms, they have open-source codecs that are available for all standard operating systems like Windows, MacOS and Linux. The different types include:
The Wave format family – Microsoft Wave format, commonly known as WAV, is the most widely used uncompressed format. All forms of WAV are PCM wrap formats with .wav as extension and store the audio data in a basic form. To provide compatibility with non-PCM audio streams, the wrapper has been altered over time.
- WAV (Waveform Audio File Format) – It is a flexible format, capable of storing very high quality audio but can’t hold any metadata describing its audio contents and its file size is limited to 4 GB.
- BWF (Broadcast Wave Format) – This format includes an extra header file that contains metadata about the audio and synchronization information (BEXT chunk). It is the default audio format of some non-linear digital audio/video workstations and has a file size limited to 4 GB.
- MBWF (Multichannel Broadcast Wave Format) – The recent evolution of Broadcast WAV, MBWF has RF64 audio with a BEXT chunk. It contains up to 18 simultaneous streams of surround audio, non-PCM data streams and a stereo ‘mixdown’. The 64-bit address header extends the file size to over 18 billion GB.
AIFF – Audio Interchange File Format was developed by Apple and Amiga and is the native format for audio on Mac OSX.
All uncompressed audio formats share some of the technical attributes like:
Bit Depth – 8-bit, 12-bit, 16-bit and 24-bit.
Sampling Rate - <44.1 kHz, 44.1 kHz, 48 kHz and 96 kHz +.