What is the difference between .m4r and .gsrt?
- Extension
 - .m4r
 - .gsrt
 
- Format
 - Binary
 - Binary
 
- Category
 - Audio
 - Audio
 
- Developer
 - Apple Inc.
 - Grandstream
 
- Description
 - M4R is an iTunes ringtone file that stores mono channel audio. They are identical to the M4A format files only that they are correctly used for ringtones.
 - Grandstream ring-tone files. Whilst this file format can contain A-Law, μ-law, GSM, G.722, G.723, G.726, G.728, or iLBC encoded audio, SoX supports reading and writing only A-Law and μ-law.
 
- MIME Type
 - audio/x-m4r
 - audio/x-gsrt
 
- Wikipedia
 - .m4r on Wikipedia