Upload M4R file from your device memory or cloud or via URL
Once uploading is complete, press the convert button
Wait until the end of the conversion and download new FLAC file
M4A is an audio file compressed using MPEG-4 technology, which has a lossy compression algorithm. The M4R file contains the ringtone in the M4A MPEG-4 file format, which uses the default audio format to store the song in the iPhone. The M4R format, like M4A, is designed to download audio to Apple devices through iTunes. Such a file can be created by converting other formats or uploading it from the official iTunes store. You don't have to look for converters or special programs, you can make m4r from m4a using standard tools of any operating system by changing the last letter of the extension manually. But for this to work like an iPhone ringtone, remember that it can only be created from songs purchased from the iTunes music store.
FLAC is a codec that compresses a lossless audio file. These files are often used in professional recording studios. However, this format implies some compression of information, so the same song in FLAC format can take up to half less memory than the original CD. And if, for example, you copy music from a CD into this format, it will not differ in any way from the original, regardless of its bit rate or frequency range. The compression ratio and bit rate vary depending on the complexity of the material to be compressed - for example, singing with a guitar lends itself to compression better than recording a symphony orchestra. FLAC is often used to create audio collections and are used for listening on premium equipment.