ios - Objective-C How do I compress the video ONLY and not the video AND text overlay? -

i using avassetexportsession , avmutablevideocomposition add text overlay on top of video , compress video. @ moment, when compressed video avassetexportpresetmediumquality, ruined quality of text overlay... dont want happen. want lower quality on video , keep text overlay on top of video sharp , not pixelated.

thank you

compress video, add text overlay.