Wrapped/Container is used to refer to a file format that encapsulates individual data streams and embeds metadata that provides information about the file’s content. These file formats are often called containers because they contain data from the file and additional information about that data.
While wrappers are often specific to a particular content category, they can also be part of a more generic classification. For example, the WAVE format is an instance of Microsoft’s RIFF classification, which also includes the AVI video format.
It is important to note that formats such as AAF and MXF, commonly used in audiovisual production, are closely related and are often called “wrappers”
Wrappers play an important role in next-generation audio and immersive audio experiences, with the advent of advanced audio formats like Dolby Atmos and DTS:X, containers have evolved to support spatial audio encoding. This technology enables a more immersive and realistic audio experience, where sound can be precisely placed in three-dimensional space, enveloping the listener in a virtual sound environment.
In addition, next-generation audio containers are being developed to support innovative audio codecs and features. These codecs allow for higher quality audio playback with higher bit rates and greater efficiency. Additionally, new container formats are being designed to accommodate object-based audio, where individual audio objects can be manipulated in real time, providing unparalleled flexibility in audio production and playback.
The choice of the wrapper can affect the compatibility of spatial audio between different devices. Some devices may not support certain containers, which may affect spatial audio quality. Therefore, it is important to choose a container that is compatible with the devices and platforms where the spatial audio content will be played.
Typical wrappers used for immersive audio include:
- MPEG-H 3D Audio
- DTS:X
- Ambisonics
- Digital Cinema Packages (DCPs)
- Unreal Engine containers
- Virtual Reality Audio (VAR)
- Virtual Vector Based Panning (VVBP)
- WAV (Waveform Audio File Format)
- AIFF (Audio Interchange File Format)
- FLAC (Free Lossless Audio Codec)
- ALAC (Apple Lossless Audio Codec)
- MP3 (MPEG Audio Layer-3)
- OGG (Ogg Vorbis)