MPEG Layer 3 Audio (MP3)

MPEG Layer 3 Audio (MP3)

Microsoft licenses two versions of an MP3 decoder from the Fraunhofer Institute, which holds the patents on MP3 encoding. DirectShow uses a decoder implemented as a native DirectShow filter, and Windows Media Player and the Windows Media Format SDK use a decoder implemented as an Audio Compression Manager (ACM) codec. The ACM version is more recent than the filter version. DirectShow applications can use the ACM version through the ACM Wrapper filter. Windows also includes an MP3 encoder, but it can create only low-bit-rate files. Several high-quality MP3 encoders are available from independent software vendors. Windows Media Player requires one of these encoders to create MP3 content; the help documentation for Windows Media Player provides a link to MP3 encoder vendors. In that documentation, the encoders are referred to as MP3 Creation Plug-Ins, but they are simply DirectShow filters.