Flash Quality
There are seven types of quality setting in Flash: unknown，low，autolow，medium，autohigh，high，best. By default Flash will publish your movie at quality="high". Setting the quality setting to "best" is a good idea if you are doing any scaling or rotating of images. Leaving the quality as high can lead to artifacting and jaggies as seen in the tests here. However, it does consume more resources.
Action Script：
_quality = "best";
or choose "Best" Quality from HTML tab at Publish Setting.
Source：http://www.airtightinteractive.com/projects/quality_test/
