OpenSL ES (Open Sound Library for Embedded Systems) is a royalty-free,

cross-platform Within computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several Computing platform, computing platforms. Some ...

, hardware-accelerated, C-language audio

API An application programming interface (API) is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how to build ...

for 2D and 3D audio. It provides access to features such as 3D positional audio and

MIDI Musical Instrument Digital Interface (; MIDI) is an American-Japanese technical standard that describes a communication protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, ...

playback. It is made for developers in the mobile and gaming industry and is working toward allowing for easy porting of applications across multiple platforms.

Overview

The OpenSL ES API has five major features: * Basic audio playback and recording * 3D audio effects including 3D positional audio * Music experience enhancing effects including bass boost and environmental reverb * Interactive music and ringtones using SP-MIDI, Mobile DLS, Mobile XMF * Buffer Queues The features of ''Audio Playback and Recording'' and ''Basic MIDI'' are common with OpenMAX AL.

Design

OpenSL ES utilizes an object oriented design to give application developers access to the audio functionality. The object model is shared with OpenMAX AL, and a device manufacturer can choose to implement one or both of the APIs. Together the two APIs give access to a wide range of functionality of the device's multimedia engine. The design goal of OpenSL ES is to give application developers access to advanced audio features such as 3D positional audio and

playback while striving for easy application porting between manufacturers and platforms. It is developed primarily for application developers in the mobile and gaming industry.

Profiles

To avoid fragmentation, OpenSL ES is divided up into three profiles: * Phone * Music * Game Each profile is designed for the respective device needs with a specific set of audio functionalities. A vendor can choose to be conformant with only one or with any combination of profiles. An application can query the OpenSL ES implementation to find out which profiles are supported. The application developer can then design their application to either work with only the common parts of the profiles, or adapt to the available functionality as given by the profiles in the device it is running on. An application developer can also specify both the minimum and the optimal profile requirements.

Development

OpenSL ES is managed by the

non-profit A nonprofit organization (NPO), also known as a nonbusiness entity, nonprofit institution, not-for-profit organization, or simply a nonprofit, is a non-governmental (private) legal entity organized and operated for a collective, public, or so ...

technology

consortium A consortium () is an association of two or more individuals, companies, organizations, or governments (or any combination of these entities) with the objective of participating in a common activity or pooling their resources for achieving a ...

Khronos Group The Khronos Group, Inc. is an open, non-profit, member-driven consortium of 170 organizations developing, publishing and maintaining royalty-free interoperability standards for 3D graphics, virtual reality, augmented reality, parallel computat ...

. The current chair of the OpenSL ES working group is Erik Noreke.

Specification versions

OpenSL ES 1.0 Specification
was released 24 March 2009. * Minor release 1.0.1 followed 24 September 2009.
OpenSL ES 1.1 Specification
was released 18 January 2011.

Implementations

* Android 2.3 exposes OpenSL ES 1.0 as part of their

Android NDK The Android Native Development Kit (NDK) provides a cross-compiling tool for compiling code written in C (programming language), C/C++ can be compiler, compiled to ARM architecture, ARM, or x86 native code (or their x86-64, 64-bit variants) for An ...

. The latency of the implementation has improved in later releases. * A full implementation of OpenSL ES 1.1 is available from SRS Labs.

References

External links

OpenSL ES website

Khronos Group website

Khronos OpenSL ES API Registry
containing specifications {{Khronos Group standards Application programming interfaces Audio libraries Video game engines