免费在线 M4R 转 SD2 转换器

M4R - is a digital multimedia container format used to store audio in mono channel mode. This format is suitable for store ringtones and it is widely used by Apple iPhone for its ringtones. Needless to say that M4R and M4A formats shares many similar features.

SDII (Sound Designer II, sometimes seen abbreviated as SD2) is a monophonic/stereophonic audio file format, originally developed by Digidesign for their Macintosh -based recording/editing products. It is the successor to the original monophonic Sound Designer I audio file format.