Upload Media/Tweet via my API -> Twitter API via oauth credentials from iOS App?



So currently in my app users can upload video/tweet via TwitterUtils client direct to Twitter’s api. I’m thinking about offloading the media upload (video) from the ios client to my API due to multiple uploads of the same media to different end points.

My question is if a user validates their Twitter session through my iOS app, can I use my API to connect to the Twitter API to upload media (via their consumer oauth info) or would the user need to validate again on my API to upload?