RealAudio是一种由RealNetworks发展的RealMedia多媒体音频文档格式，仅指RealPlayer中能够识别的音频文档，也可以理解为real格式的音频文档。

Realaudio有很多版本，realaudio 1,realaudio 2,3最近已经到了realaudio 11了，这些格式不同，依赖的媒体播放器也不同，有些rm文档，能播放出来，有些又不能，这个时候可以看一下是不是realaudio编码的版本问题。

RealAudio is a proprietary audio format developed by RealNetworks and first released in April 1995. It uses a variety of audio codecs, ranging from low-bitrate formats that can be used over dialup modems, to high-fidelity formats for music. It can also be used as a streaming audio format, that is played at the same time as it is downloaded. In the past, many internet radio stations used RealAudio to stream their programming over the internet in real time. In recent years, however, the format has become less common and has given way to more popular audio formats. RealAudio was heavily used by the BBC websites until 2009, though it was discontinued due to its declining use. BBC World Service, the last of the BBC websites to use RealAudio, discontinued its use in March 2011.