Windows的资源管理器或Finder中进行此项操作,而不是在iTunes中更改后缀。{"smallUrl":"https:\/\/www.wikihow.com\/images_en\/thumb\/0\/02\/Get-Ringtones-for-the-iPhone-Step-13-Version-3.jpg\/v4-460px-Get-Ringtones-for-the-iPhone-Step-13-Version-3.jpg","bigUrl":"https:\/\/www.wikihow.com\/images_en\/0\/02\/Get-Ringtones-for-the-iPhone-Step-13-Version-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":760,"bigHeight":570}13将扩展名从“.m4a”更改为“.m4r”。