Help! Major reduction in video quality when I upload a video from Replay 360 to Storyline 360

When I record my screen in Replay 360 and publish the video, the quality is fine. However, Since the editing options are limited in Replay, I upload the video in Storyline to finish editing. However, when I publish it from Storyline, the quality is so poor it's unusable. I've already tried  clicking in the Design tab and adjusting the custom width and height to 1440 x 1080 and then publishing it in 1080p HD and the highest audio and video quality settings. Even with these tweaks, the video quality is still blurry. (However, when I publish a 30-second video in these settings, the quality is higher than a 3 minute video with the same settings. And  when I don't adjust the height and width at all from the Design tab, the quality is even worse). I'm  at a loss here on what else to try. Oh, and why does my video always start with a one second black screen in Storyline when it is published, when it was never part of the original video in Replay?