What are the differences, advantages and disadvantages of mp3, amr, mmf and chord when ringing? Please elaborate.

Simply put, the advantage of MP3 is that it can achieve the best sound quality. The disadvantage is that the bit rate is usually high and the file is usually large. But now good mobile phones can be extended to 1G or 2G memory cards.

AMR is a recording format, which is commonly used in Nokia's low-end mobile phones. The disadvantage of this ringtone is that the sound quality is not very good, but the ringtone code rate of this format is very low, so the ringtone file is relatively small.

MMF, I don't quite understand. It seems to be used more on Korean mobile phones.

Chord ringtone mainly refers to the ringtone of MID. This ringtone file is very small and the sound quality is good. /kloc-the sound quality above 0/6 chords is very good, but unfortunately there are only the sounds of instruments such as Didi, and there is no real person's voice (Yamaha chords seem to have real people's voices, but I can't understand them).

Chord ringtone is the most widely used ringtone format, which is supported by general mobile phones.

But MP3 is the mainstream of this era.