IEEE Std 1857.7-2018 pdf download – IEEE Standard for Adaptive Streaming.
5. Conventions The following naming conventions apply in this standard.   Elements in an Extensible Markup Language (XML) document are identified by an uppercase first letter and in boldface, e.g., Element. To express that an element Element1 is contained in another element Element2, one may write Element2.Element1. If an element’s name consists of two or more combined words, camel-casing is typically used, e.g., ImportantElement. Elements may be present either exactly once or with the minimum and maximum occurrence defined by <minOccurs> … <maxOccurs>.   Attributes in an XML document are identified by a lowercase first letter as well as by being preceded by a ‘@’ (“at” sign), e.g., @attribute. To point to a specific attribute @attribute contained in an element Element, one may write Element@attribute. If an attribute’s name consists of two or more combined words, camel-casing is typically used after the first word, e.g., @veryImportantAttribute. Attributes may be assigned a status in the XML as mandatory (M), optional (O), optional with default value (OD), and conditionally mandatory (CM).   Namespace qualification of elements and attributes is used in accordance with XML standards, in the form of namespace:Element or @namespace:attribute. The fully qualified namespace will be provided in the schema fragment associated with the declaration.   Variables defined in the context of this standard are specifically highlighted with italics, e.g.. InternalVariable.   Structures that are defined as part of the hierarchical data model are identified by an uppercase first letter, e.g., Period, Adaptation Set, Representation, Segment.
6. Architecture The architecture of Audio and Video Coding Standard Adaptive Streaming over HTTP (shortened as AVS-AS) is illustrated in Figure 1. AVS-AS mainly specifies the formats of media presentation description (MPD) (a modified version of the MPD defined in ISO/IEC 23009-1) 5 and segment for adaptive streaming over HTTP.   MPD MPD is formatted description of media presentation for providing streaming services. Specifically, the resource identifiers of segments and the context of identified resource in media presentation are defined. The resource identifier is HTTP-URL and may be combined with byte range.   Segment Segment format refers to the format of the resource identified in an MPD and requested by IETF RFC 2616. Segments usually contain coded media data and metadata.