ISO IEC 23000-19:2018 pdf download

ISO IEC 23000-19:2018 pdf download.Information technology Multimedia application format (MPEG-A) Part 19: Common media application format (CMAF) for segmented media.
Common Media Application Format (CMAF) combines and constrains several MPEG specifications to define a multimedia format that is optimized for delivery of a single adaptive multimedia presentation to a variety of devices, using a variety of adaptive streaming, broadcast, download, and storage methods.
Several MPEG specifications have been adopted for much of the video delivered over the Internet and other IP networks (cellular, cable, broadcast, etc.). Various organizations have taken MPEG’s core coding, file format and system standards and combined them into their own specifications for their specific application. While these specifications are similar, their differences result in unnecessary duplication of engineering effort and duplication of identical content in slightly different formats, which results in increased storage and delivery costs.
CMAF provides a common media specification that application specifications, such as MPEG Dynamic Adaptive Streaming over [ITTP (DASH), can reference and a common media format that allows a single encoded multimedia presentation to be used by many applications.
ISO IEC 23000-19 specifies the CMAF multimedia format, which contains segmented media objects optimized for streaming delivery and decoding on end user devices in adaptive multimedia presentations.
CMAF specifies a track format derived from the ISO Base Media File Format, then derives addressable media objects from CMAF tracks that can be used for storage and delivery.
CMAF specifies sets of tracks that share encoding and packaging constraints that enable the selection of multiple tracks to form a multimedia presentation and allow seamless switching of alternative encodings of the same content at different bit rates, frame rates, resolution, etc.
CMAF specifies a hypothetical application model that determines how tracks in a CMAF presentation are intended to be combined and synchronized to form a multimedia presentation. The model abstracts delivery to allow any delivery method. The hypothetical application model assumes a manifest and player, but CMAF does not specify a manifest, player, or delivery protocol, with the intent that any that support the hypothetical application model can be used.
CMAF specifies media profiles and brands that constrain media encoding and packaging of CMAF tracks to enable seamless adaptive switching of tracks and allow devices to identify compatible content by its brand.
First-time readers of ISO IEC 23000-19 are advised to start with Clause 6 for a description of the objects and terminology specified, the CMAF object model, and the hypothetical application model, which defines how these objects can be combined to form adaptive multimedia presentations.
The normative specifications in Clause 7 through Clause 12 are terse to facilitate development and testing and assume an understanding of Clause 6. Clause 7 specifies ISO Base Media File Format boxes and structures such as movie fragments and tracks that are used to construct all CMAF media objects. Clauses 8 through 11 contain details specific to encryption, audio, video, and subtitle tracks. Clause 12 specifies the combination of CMAF tracks and media profiles into CMAF presentations. It also
CMAF defines a hypothetical application model so that encoding to that model results in consistent CMAF track encoding, representation in manifests, track selection, late binding, synchronization, decoding, and rendering of CMAF presentations.
Decoding requirements can be inferred from encoding constraints and the hypothetical application model, but are not directly specified by CMAF. CMAF does not specify manifest formats or associated resource identification and transport. However, CMAF does specify CMAF addressable media objects derived from encoded CMAF fragments, which can be referenced as resources by a manifest. External specifications can define how a manifest describes a CMAF presentation, including identifying CMAF

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