摘要：Audio formats are improving in terms of compression ratio as well as of audio quality,
and new formats like OGG, FLAC or AAC have started to dethrone the former king of digital
music formats MP3. The contest of formats however takes place at the level of protected formats
too, i.e. integration of audio codec and DRMs. At this level proprietary formats still prevail,
and interoperability - demanded by consumers and expert groups - consequently falls short.
This article gives some background on popular audio formats and their connection to DRM systems,
and discusses ways to achieve interoperability.
