22.0.7 Lines become slightly jagged after exporting video

check your publish settings. Make sure they are on the highest levels.

If you are using an ActionScript 3.0 FLA to do your animating for video (you should be), you can go to frame 1 of the timeline, open the Actions panel, and put in this code:

stage.quality = "16x16";

That will then make the export to video look as good as possible

that looks like pixelation.

drawing at (or even better above) final scale will prevent that.