Full name | RealAudio, Version 10 |
Description | File format for audio. Provides for four different codecs; see Relationships to Other Formats, below.
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Production phase | Generally a final-state (end-user delivery) format. |
Relationship to other formats | |
Supertype of | RealAudio_RA (RealAudio codec) |
Supertype of | RealAudio_AAC (AAC codec) |
Supertype of | RealAudio_LL (lossless codec) |
Supertype of | RealAudio_MC (multichannel codec) |
May contain | RealAudio codec, not separately documented |
May contain | AAC codec |
May contain | RealAudio lossless codec, not separately documented |
May contain | RealAudio multichannel codec, not separately documented |
Disclosure | Proprietary format with little public documentation, although licenses for certain classes of developers may provide access to source code. |
Documentation | Various promotional and instructional documents from RealNetworks, Inc.; see list in Useful References below. |
Adoption | Very widely adopted for streaming web content and other online applications. |
Licensing and patent claims | Licensing for RealAudio and RealVideo, and for related production and delivery tools, is described at https://helixcommunity.org/content/licenses, an entity of RealNetworks, Inc. Licensing includes open source and research and development arrangements that provide access to the source code for the codecs. |
Transparency | Depends upon algorithms and tools to read; will require sophistication to build tools. |
Self-documentation | [Embedded bibligraphic or descriptive metadata is included in online examples, e.g., title, artist, genre. This writer could not find documentation as of April 2004; RealAudio may share metadata structure with RealVideo.] |
External dependencies | Playback of surround sound requires multiple loudspeakers. |
Technical protection considerations | [RealAudio likely to share technical protection devices with RealVideo.] |
Normal rendering | Good support. |
Fidelity (support for high audio resolution) | Moderate to excellent, depending upon the codec selected; for mono and stereo recordings, the lossless codec offers the highest fidelity while the AAC codec will provide the best result for compressed sound. |
Support for multiple channels | All codecs support mono and stereo; the multichannel codec supports 5 or 6 channels (5.1 audio). Presumably the multichannel codec can be used for multiple channel sound not intended to represent aural space. |
Support for downloadable or user-defined sounds, samples, and patches | Not applicable |
Functionality beyond normal video rendering | A sequence of Web pages can be synchronized for display with the playback of streaming media in a RealMedia player when HTML-page URLs are embedded in a RealMedia clip. |