M4A
AMR iifayile
I-M4A yifomati yefayile yomsindo esondeleleneyo neMP4. Ibonelela ngoxinzelelo oluphezulu lweaudio ngenkxaso yemetadata, iyenza ilungele usetyenziso olwahlukeneyo.
I-AMR (I-Adaptive Multi-Rate) yifomathi yocinezelo lwe-audio elungiselelwe ikhowudi yentetho. Iqhele ukusetyenziswa kwiifowuni eziphathwayo ukwenzela ukurekhoda kwelizwi kunye nokudlala kwakhona.