New registration trees may be created by IETF Standards Action for external registration and management by well-known permanent organizations (e.g. These registration trees were first defined in November 1996 (obsoleted RFC 2048 - currently RFC 6838). Currently the following trees are created: standard (no prefix), vendor ( vnd. For the efficiency and flexibility of the media type registration process, different structures of subtypes can be registered in registration trees that are distinguished by the use of tree prefixes. Subtypes Ī subtype typically consists of a media format, but it may or must also contain other content, such as a tree prefix, producer, product or suffix, according to the different rules in registration trees.Īll media types should be registered using the IANA registration procedures. Īn unofficial top-level type in common use is chemical. By December 2020, the registered types included the foregoing, plus font, example, and model. As of November 1996, the registered types were: application, audio, image, message, multipart, text and video. The "type" part defines the broad use of the media type. Parameter values are usually case-sensitive, but may be interpreted in a case-insensitive fashion depending on the intended use. Types, subtypes, and parameter names are case-insensitive. In this example, text is the type, html is the subtype, and charset=UTF-8 is an optional parameter indicating the character encoding. Mime-type = type "/" subtype * Īs an example, an HTML file might be designated text/html charset=UTF-8. Media types are also used by other internet protocols such as HTTP and document file formats such as HTML, for similar purposes. Media types were originally defined in Request for Comments RFC 2045 (MIME) Part One: Format of Internet Message Bodies (Nov 1996) in November 1996 as a part of the MIME (Multipurpose Internet Mail Extensions) specification, for denoting type of email message content and attachments hence the original name, MIME type. The Internet Assigned Numbers Authority (IANA) is the official authority for the standardization and publication of these classifications. Their purpose is somewhat similar to file extensions in that they identify the intended data format. ( April 2023) ( Learn how and when to remove this template message)Ī media type (formerly known as a MIME type) is a two-part identifier for file formats and format contents transmitted on the Internet. There is a discussion about this on Ferney. This article may be confusing or unclear to readers.
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