OpenSL ES (Open Sound Library for Embedded Systems) is a royalty-free, cross-platform, hardware-accelerated,
C-language audio
API
An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...
for 2D and 3D audio. It provides access to features such as
3D positional audio and
MIDI
MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
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
MIDI
MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
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) or non-profit organisation, also known as a non-business entity, not-for-profit organization, or nonprofit institution, is a legal entity organized and operated for a collective, public or social benefit, in co ...
technology
consortium
A consortium (plural: consortia) 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 ...
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 computation ...
. The current chair of the OpenSL ES working group is Erik Noreke.
Specification versions
OpenSL ES 1.0 Specificationwas released 24 March 2009.
* Minor release 1.0.1 followed 24 September 2009.
OpenSL ES 1.1 Specificationwas released 18 January 2011.
Implementations
*
Android 2.3 exposes OpenSL ES 1.0 as part of their NDK. The
latency of the implementation has improved in later releases.
* A full implementation of OpenSL ES 1.1 is available from
SRS Labs
SRS Labs, Inc. was a Santa Ana, California-based audio technology engineering company that specialized in audio enhancement solutions for wide variety of consumer electronic devices. Originally a part of Hughes Aircraft Company, the audio division ...
.
See also
*
OpenMAX AL - Application level multimedia API
*
OpenAL
OpenAL (Open Audio Library) is a cross-platform audio application programming interface (API). It is designed for efficient rendering of multichannel three-dimensional positional audio. Its API style and conventions deliberately resemble those ...
- advanced audio API for desktop and mobile
*
Advanced Multimedia Supplements
In computing, the Advanced Multimedia Supplements (also JSR-234 or AMMS) is an API specification for the Java ME platform. Practically speaking, it is an extension to JSR 135 Mobile Media API providing new features, such as positional 3D audio p ...
(JSR 234) - Java API for mobile devices
References
External links
OpenSL ES websiteKhronos Group websiteKhronos OpenSL ES API Registrycontaining specifications
{{Khronos Group standards
Application programming interfaces
Audio libraries
Video game engines