It does. AACはMP4ファミリーの損失コーデックで、同じビットレートでMP3より音質が良く、Appleデバイスのデフォルトです。. That determines whether the corrected audio can be written back exactly or has to be re-encoded.
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 AAC の音量を正常化 rather than before it means the conversion works from the file you finally settled on.