Media dispatch protocol
Encyclopedia
The Media Dispatch Protocol (MDP) was developed by the Pro-MPEG
Media Dispatch Group
to provide an open standard for secure, automated, and tapeless delivery of audio, video and associated data files. Such files typically range from low resolution content for the web to HDTV and high-resolution digital intermediate files for cinema production.
MDP is essentially a middleware
protocol that decouples the technical details of how delivery occurs from the business logic that requires delivery. For example, a TV post-production company might have a contract to deliver a programme to a broadcaster. An MDP agent
allows users be able to deal with company and programme names, rather than with filenames and network endpoints. It can also provide a delivery service as part of a service oriented architecture
.
MDP acts as a communication layer between business logic and low-level file transfer mechanisms, providing a way to securely communicate and negotiate transfer-specific metadata about file packages, delivery routing, deadlines, and security information, and to manage and coordinate file transfers in progress, whilst hooking all this information to project, company and job identifiers.
MDP works by implementing a 'dispatch transaction' layer by which means agents negotiate and agree the details of the individual file transfers required for the delivery, and control, monitor and report on the progress of the transfers. At the heart of the protocol is the 'Manifest' - an XML document that encapsulates the information about the transaction.
MDP is based on existing open technologies such as XML
, HTTP and TLS
. The protocol is specified in a layered way to allow the adoption of new technologies (e.g. Web Services protocols such as SOAP and WSDL
) as required.
Since early 2005, multiple implementations based on draft versions of the Media Dispatch Protocol have been in use, both for technical testing, and, since April 2005, for real-world production work. The experience with these implementations, both at the engineering level, and at the practical production level, has been rolled into the 1.0rcX specification.
A newer, and more complete, open-source reference implementation is now available on SourceForge
.
Media Dispatch Protocol (MDP) has been standardized by a SMPTE Working Group under the S22 Committee. This work has been published as SMPTE 2032-1-2007 (MDP specification), 2032-2-2007 (MDP/XML
/HTTP mapping specification) and 2032-3-2007 (MDP Target pull profile specification). MDP is also supported by SMPTE Engineering Guideline EG 2032-4-2007 covering the use of MDP.
Pro-MPEG
Pro-MPEG – the Professional-MPEG Forum – is an association of broadcasters, program makers, equipment manufacturers, and component suppliers with interests in realizing the interoperability of professional television equipment, according to the implementation requirements of...
Media Dispatch Group
Media dispatch group
The Media Dispatch Group was created in 2003 as an activity of the Professional-MPEG Forum to create a vendor-neutral open technology to create integrated solutions for the professional exchange of large media files securely over IP networks...
to provide an open standard for secure, automated, and tapeless delivery of audio, video and associated data files. Such files typically range from low resolution content for the web to HDTV and high-resolution digital intermediate files for cinema production.
MDP is essentially a middleware
Middleware
Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...
protocol that decouples the technical details of how delivery occurs from the business logic that requires delivery. For example, a TV post-production company might have a contract to deliver a programme to a broadcaster. An MDP agent
Software agent
In computer science, a software agent is a piece of software that acts for a user or other program in a relationship of agency, which derives from the Latin agere : an agreement to act on one's behalf...
allows users be able to deal with company and programme names, rather than with filenames and network endpoints. It can also provide a delivery service as part of a service oriented architecture
Service-oriented architecture
In software engineering, a Service-Oriented Architecture is a set of principles and methodologies for designing and developing software in the form of interoperable services. These services are well-defined business functionalities that are built as software components that can be reused for...
.
MDP acts as a communication layer between business logic and low-level file transfer mechanisms, providing a way to securely communicate and negotiate transfer-specific metadata about file packages, delivery routing, deadlines, and security information, and to manage and coordinate file transfers in progress, whilst hooking all this information to project, company and job identifiers.
MDP works by implementing a 'dispatch transaction' layer by which means agents negotiate and agree the details of the individual file transfers required for the delivery, and control, monitor and report on the progress of the transfers. At the heart of the protocol is the 'Manifest' - an XML document that encapsulates the information about the transaction.
MDP is based on existing open technologies such as XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
, HTTP and TLS
Transport Layer Security
Transport Layer Security and its predecessor, Secure Sockets Layer , are cryptographic protocols that provide communication security over the Internet...
. The protocol is specified in a layered way to allow the adoption of new technologies (e.g. Web Services protocols such as SOAP and WSDL
Web Services Description Language
The Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service provides a machine-readable description of how the service can be called, what parameters it expects and what data structures...
) as required.
Since early 2005, multiple implementations based on draft versions of the Media Dispatch Protocol have been in use, both for technical testing, and, since April 2005, for real-world production work. The experience with these implementations, both at the engineering level, and at the practical production level, has been rolled into the 1.0rcX specification.
A newer, and more complete, open-source reference implementation is now available on SourceForge
SourceForge
SourceForge Enterprise Edition is a collaborative revision control and software development management system. It provides a front-end to a range of software development lifecycle services and integrates with a number of free software / open source software applications .While originally itself...
.
Media Dispatch Protocol (MDP) has been standardized by a SMPTE Working Group under the S22 Committee. This work has been published as SMPTE 2032-1-2007 (MDP specification), 2032-2-2007 (MDP/XML
XML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
/HTTP mapping specification) and 2032-3-2007 (MDP Target pull profile specification). MDP is also supported by SMPTE Engineering Guideline EG 2032-4-2007 covering the use of MDP.