Part 1 “Binary MPEG format for XML” (BiM) was originally developed a the technology to compress MPEG-7 Descriptors and Description Schemes and placed in MPEG-7 Part 1. BiM was then made a generic technology and moved to MPEG-B part 1. It provides a standard set of generic technologies to transmit and compress XML documents, addressing a broad spectrum of applications and requirements. High compression efficiency is achieved by having a shared knowledge on the schema between encoder and decoder. BiM also provides fragmentation mechanisms for ensuring transmission and processing flexibility.
Part 2 “Fragment Request Unit” specifies a technology enabling a terminal to request XML fragments of immediate interest. This significantly reduces processing and storage requirements at the terminal and can enable applications on constrained devices that would not otherwise be possible.
Part 3 “XML Representation of IPMP-X Messages” provides an XML representation – with extensions – of the IPMP-X messages defined in MPEG-4 part 13.
Part 4 “Codec Configuration Representation” provides a compressed digital representation of a video decoder and of the corresponding bitstream, assuming that the receiving terminal shares a library of video coding tools with the transmitter. Reconfigurable Video Coding gets a more complete treatment later.
Part 5 “Bitstream Syntax Description Language” provides a normative grammar to describe, in XML, the high-level syntax of a bitstream. The resulting XML document is called a Bitstream Syntax Description (BSD). BSD does replace the original binary format and, in most cases, it does not describe the bitstream on a bit-per-bit basis, but rather its high-level structure, e.g., how the bitstream is organized in layers or packets of data. BSD is itself scalable, i.e. it may describe the bitstream at different syntactic layers (e.g., finer or coarser levels of detail), depending on the application. Morea bout this later.
Part 7 “Common Encryption for ISO Base Media File Format Files” specifies encryption and key mapping methods to enable decryption of a file using different Digital Rights Management (DRM) and key management systems. It defines encryption algorithms and encryption related metadata necessary to decrypt the protected streams, but rights mappings, key acquisition and storage, DRM content protection compliance rules, etc., are left to the DRM system(s). For instance, identification of decryption key is done via stored key identifiers (KIDs), but a DRM-specific method specifies how the KID identified decryption key is protected and located.
Part 8 “Coding-independent code-points” collects and defines code points and fields that establish properties of a video or audio stream outside of the compression encoding and bit rate. Examples of properties are the appropriate interpretation of decoded video or audio data or the characteristics of such signals before the signal is compressed by an encoder designed to compress such an input signal.
Part 9 “Common encryption of MPEG-2 transport streams” specifies a common media encryption format for use in MPEG-2 Transport Streams. The encryption format is interoperable with the format MPEG-B Part 7 in the sense that it is possible to convert between encrypted MPEG-2 Transport Streams and encrypted ISO base media file format files without re-encryption.
Part 10 “Carriage of Timed Metadata Metrics of Media in ISO Base Media File Format” specifies the carriage of timed metadata in files belonging to the MPEG file family. The metadata are ‘green’ metadata (related to energy consumption) and quality measurements of the associated media data (related to video quality metrics).
Part 11 “Green Metadata” specifies the format of the following metadata:
- Reduced decoder power consumption
- Reduced display power consumption
- Media selection for joint decoder and display power reduction
- Quality recovery after low-power encoding.
Appropriate use of these metadata help reduce energy usage during media consumption in two modalities: 1) without any degradation in the Quality of Experience (QoE) and 2) with some QoE degradation to get larger energy savings.
Part 12 “Sample variants in the ISO base media file format” defines the carriage of Sample Variants, i.e. assembled media samples replacing an original sample, in MPEG file format files.