M4A
AMR mafayilo
M4A ndi mtundu wamafayilo omvera womwe umagwirizana kwambiri ndi MP4. Imapereka kupsinjika kwapamwamba kwamawu ndi chithandizo cha metadata, ndikupangitsa kuti ikhale yoyenera kugwiritsa ntchito zosiyanasiyana.
AMR (Adaptive Multi-Rate) ndi mtundu wamawu wokongoletsedwa kuti azitha kukopera mawu. Amagwiritsidwa ntchito kwambiri m'mafoni a m'manja pojambula mawu komanso kusewera.