Convert M4R to CAF

An audio editor or Apple Core Audio project may require CAF instead of an iPhone ringtone file. Converting the audio makes it usable in that workflow, but does not restore quality lost in AAC compression.

What M4R contains

M4R is the file extension Apple uses for iPhone ringtones. It usually contains AAC audio in an MPEG-4 container, similar to M4A, and is used by ringtone tools and Apple devices.

What CAF offers

CAF (Core Audio Format) is an audio container used by Apple software and Core Audio workflows. It can store uncompressed PCM or codecs such as AAC and ALAC. Its 64-bit structure supports files beyond the traditional WAV size limit; the format is useful when an editing or recording application specifically requires CAF.

Convert with FFmpeg

FFmpeg is a cross-platform desktop option that can decode supported M4R audio and write CAF. Install FFmpeg, open a terminal or command prompt in the folder containing the ringtone, and run:

ffmpeg -i "ringtone.m4r" -c:a pcm_s16le "ringtone.caf"

Replace the filenames with the actual source and destination names. This command writes 16-bit PCM and normally keeps the source sample rate and channel count. If the destination application requires specific settings, add options such as -ar 44100 for a 44.1 kHz sample rate or -ac 2 for stereo.

Quality and compatibility

M4R commonly contains lossy AAC. Converting it to PCM decodes the audio but cannot recover detail removed by compression, and the CAF output will usually be larger. Protected or unsupported source audio may not decode in FFmpeg. Changing an AIFF filename extension to .caf does not convert the file: AIFF and CAF use different containers and headers.