OpenMax

http://www.khronos.org/openmax/

OpenMAX Overview

OpenMAX - The Standard for Media Library Portability

OpenMAX™ is aroyalty-free, cross-platform API that provides comprehensive streaming media codec and application portabilitybyenabling accelerated multimedia components to be developed, integrated and programmedacrossmultiple operating systems and silicon platforms. The OpenMAX API will be shipped with processors to enable library and codec implementers to rapidly and effectively make use of the full acceleration potential of new silicon - regardless of the underlying hardware architecture.

OpenMAX -便携设备媒体库标准

OpenMAX™是无授权费的,跨平台的应用程序接口API，通过使媒体加速组件能够在开发、集成和编程环节中实现跨多操作系统和处理器硬件平台，提供全面的流媒体编解码器和应用程序便携化。OpenMAX API将会与处理器一同提供，以使库和编解码器开发者能够高速有效地利用新器件的完整加速潜能-无需担心其底层的硬件结构。 

Background

z??S bZ0Development of multimedia hardware platforms is gathering pace as consumer demand grows for improved functionality from applications such as video, audio, voice, and 3D on platforms such as diverse as smartphones, audio and video media players and games consoles. In general, this class of product requires high-performance processing and high data throughput capabilities. Consequently, a variety of solutions has evolved, each designed to accelerate multimedia applications. Examples include:

• General purpose processors with specific multimedia extensions
• Low level hardware accelerators,
• Multiple processor architectures including DSPs
• Dedicated hardware video decoders

$k#h:k&i[,e0One of the key challenges with all of these architectural variants is todevelop efficient code. Even though compilers are generally provided, it is rare to be able to exploit the full potential of the entire architecture from a high-level programming language. The outcome is that large portions of the application are often written in assembly language to specifically target the hardware platform. The proliferation of different multimedia hardware solutions means that software must be re-written and optimized for each new platform that it is ported to.51Testing软件测试网2CDz7}'_(a(N

:Y%kLxukXw%o0The effect of this inefficiency in implementation is to delay the introduction of new products, increase development costs and reduce product quality, which ultimately slows down innovation in the multimedia domain at a time when market demand is growing.

A New Open Standard

^-d7S&QW$m0To address this issue, the OpenMAX Working Group has been formed by the Khronos Group, to define a set of standard, open Application Programming Interfaces (APIs) for multimedia applications. The goal of this open standard is to reduce the cost and complexity of porting multimedia software to new processors and architectures.

0eI)x K'i0By agreeing a common specification for middleware applications such as multimedia codecs, graphics libraries and other functions for video, image, audio, voice and speech, it will be possible for the developer community to focus on differentiating their products rather than the repeated implementation of common functionality. This will ensure that new products can be brought to market sooner, and will support a broader range of hardware platforms.51Testing软件测试网/I6F d$JsR#Q'vf([

1. OpenMAXIL(Integration Layer)
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   u&D B%~J E0OpenMAXILserves as a low-level interface for audio, video, and imaging codecs used in embedded and/or mobile devices. It gives applications and media frameworks the ability to interface with multimedia codecs and supporting components (i.e., sources and sinks) in a unified manner. The codecs themselves may be any combination of hardware or software and are completely transparent to the user. Without a standardized interface of this nature, codec vendors must write to proprietary or closed interfaces to integrate into mobile devices. The principal goal of the IL is to give codecs a degree of system abstraction using a specialized arsenal of features, honed to combat the problem of portability among many vastly different media systems.
2. OpenMAX DL (Development Layer)51Testing软件测试网-@&k,|;g s3a9p
   OpenMAX DL defines an API which contains a comprehensive set of audio, video and imaging functions that can be implemented and optimized on new processors by silicon vendors and then used by codec vendors to code a wide range of codec functionality. It includes audio signal processing functions such as FFTs and filters, imaging processing primitives such as color space conversion and video processing primitives to enable the optimized implementation of codecs such as MPEG-4, H.264, MP3, AAC and JPEG. OpenMAX supports acceleration concurrency via both iDL, which usesOpenMAXILconstructs, and aDL which adds asynchronous interfaces to the OpenMAX DL API.
3. OpenMAX AL (Application Layer)
   b jHk W!w AU0The OpenMAX AL API defines a set of APIs providing a standardized interface between an application and multimedia middleware where multimedia middleware provides the services needed to perform expected API functionality. TheALprovides application portability with regards to the multimedia interface.

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Driving Collaboration

+Z+l'CE-o3~'W*q"E0OpenMAX is a non-proprietary, royalty-free standard, primarily targeted at middleware developers producing multimedia codecs, games engines and graphics libraries. OpenMAX is widely applicable to all applications where multimedia performance is a critical issue, including smartphones, games consoles, digital televisions and set-top boxes. Through collaboration and support from a growing number of leading stakeholders, the standard will be developed and promoted, with wide industry support and adoption encouraged.

The working group welcomes the input and experience of existing Khronos members, and encourages new members with multimedia knowledge to join and help ensure that the specifications deliver benefits that are relevant to the entire industry. This includes semiconductor manufacturers, independent software vendors, intellectual property vendors, operating system companies and the OEM or product development companies that supply end users.51Testing软件测试网0{5O9p+j9uO,a#B Q