MP3d

MP3d refers to the three-dimensional aspects of data encoded within an MP3 audio file. While the MP3 format itself is primarily designed for storing and playing back two-dimensional (stereo or mono) audio, the term "MP3d" can be used colloquially or in specific contexts to suggest the potential for spatial audio information to be represented or inferred within an MP3 file. This is not a standard feature of the MP3 format itself.

The MP3 standard, officially known as MPEG-1 Audio Layer III or MPEG-2 Audio Layer III, focuses on lossy compression of digital audio. Its algorithms are optimized to remove psychoacoustically irrelevant information, reducing file size without significant perceived loss of quality for typical stereo listening. It does not inherently support the encoding of discrete audio channels beyond stereo or the metadata necessary for advanced spatial audio rendering, such as object-based audio or binaural cues.

However, in certain specialized applications or experimental setups, information that contributes to a spatial audio experience might be embedded within the MP3 stream. This could involve techniques where different audio elements are mixed into a stereo MP3 in a way that simulates directionality or depth, or where external software interprets existing stereo information to create a 3D effect. True three-dimensional audio typically requires dedicated formats and encoding schemes that explicitly support multiple audio channels or spatial metadata, which MP3 does not natively provide.