iPhone ringtones are slightly different than other ringtones. First of all the format is based on MPEG-4 but renamed to have an M4R extension (R for ringtone) and secondly the sound spectrum is quite different from other mobile phones.
MPEG-4 Part 14 was based on Apple’s QuickTime container format. MPEG-4 Part 14 is essentially identical to the QuickTime MOV format, but formally specifies support for Initial Object Descriptors (IOD) and other MPEG features.
.MP4 versus .M4A and .M4R file extensions
The existence of different file extensions for naming audio-only MP4 files has been a source of confusion among users and multimedia playback software. Since MPEG-4 Part 14 is a container format, MPEG-4 files may contain any number of audio, video, and even subtitle streams, making it impossible to determine the type of streams in an MPEG-4 file based on its filename extension alone.
In response, Apple Inc. started using and popularizing the .m4a file extension. Software capable of audio/video playback should recognize files with either .m4a or .mp4 file extensions, as would be expected, as there are no file format differences between the two. Most software capable of creating MPEG-4 audio will allow the user to choose the filename extension of the created MPEG-4 files.
The same is true for .m4r which essentially is the same as an .m4a file but with a different extension. The dedicated extension ensures that when an .m4r file is dragged to iTunes for example - the ringtone is automatically recognized and installed - ready to be synced with the iPhone.
iPhone audio specifications
Frequency response: 20Hz to 20,000Hz
Audio formats supported: AAC, Protected AAC, MP3, MP3 VBR, Audible (formats 1, 2,
and 3), Apple Lossless, AIFF, and WAV
User-configurable maximum volume limit
iPhone ringtones from
$23.76 per year
iPhone ringtones from $1.98
per month
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