RealAudio

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computing: data formats: media formats: audio formats: RealAudio

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Overview

RealAudio is a proprietary format for storing compressed lossy audio. Due to its proprietary nature, the exact format is not publicly documented, and conversion from RealAudio to other formats is generally difficult to accomplish due to a lack of tools. The format is owned by RealNetworks.

The non-decodability of RealAudio is one of its selling points to content providers, in that a reasonable guarantee can be provided that any content encoded with RealAudio will not be easily copyable into other formats. When RealAudio is streamed using RealNetworks's proprietary rtsp format, it cannot even be saved to hard disk for replaying unless a "recordable" flag is set.

Notes

I'm not sure about this, but my understanding is that:

• since the format is not documented, you have to have a code library from RealNetworks (in order to read or write it)...
• ...which requires a license agreement...
• ...which stipulates that it must not be used to create a program which can convert a RealAudio file (or stream) into any other format.

The only other alternative would be to reverse-engineer the format, which would be in violation of the DMCA (at least, in the U.S.).

Presuming all of the above is true, then, any program which converts from RealAudio format to any other format would involve either violating the code library's EULA or else violating the DMCA (perhaps both).

Links

Reference

• Wikipedia: RealAudio | RealNetworks

Practical

• dbPowerAMP, a Windows program with codecs for converting to/from many audio formats including RealAudio
• How to download Real Audio streams and convert Real Audio to MP3: blog entry with some how-to tips