Very much so. M4Aは、iTunesやApple MusicのファイルのデフォルトであるAACまたはALACオーディオを保持するMP4コンテナです。. That determines both the headroom available and whether the saving costs you anything in fidelity.
透明度の決定は，透明度の変更を行う段階である。 That is the step most people actually came for, and doing it after M4A を圧縮 rather than before it means the conversion works from the file you finally settled on.
