Final Cut Pro exports larger than original file?
So, in this world of conferences gone virtual, I've received a video file of a full day of a virtual conference that I am trying to cut down into individual sessions. The original file is about 5 hours long, just under 5GB size, video codec is H.264, aucio is AAC, res is 1920 x 1080. I am trying to cut this footage into four approx 1-hour files. But when I cut this file into four smaller parts, each of these new files is being exported as 6 - 9GB files. The settings are the same - H.264, AAC, 1920x1080 -- can someone please explain how a 5GB, 5-hour long video is becoming four 9GB, 1-hour long videos when I try to cut it down? I'm not adding any titles or frills, literally just chopping it up and trying to export the sessions separately, so how am I about to end up with 30+ GB of files to upload when the original is only 5GB to begin with? I'm pulling my hair out over here. I'm running final cut version 10.4.9
MacBook Pro 13″, macOS 10.15