It does. FLACは無損失圧縮で、デコード時にソースとビット同一で、WAVの約半分のサイズです。. That determines whether the retimed result can be written back cheaply or has to be fully 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 FLAC の速度を変更 rather than before it means the conversion works from the file you finally settled on.