Exports looks low res

I am uploading full 1080p res video, when I’m working within Recast to edit the file, add captions, etc. the quality seems great - however even though I’m exporting at 1080p, the quality of the video is diminished and looks low resolution.

Please see the attached screenshot - on the left is exported mp4 in quicktime and on the right is the editing mode in Recast, you can see the lack of definition in the text/captions and the host’s face, not to mention some issues with colour reproduction (noticeable difference in pinks). I have been very impressed with the quality Recast’s captions, however the lower resolution exports is making me consider other products.