working in animation project to be broadcasted on a TV channel as HD1080 50i,
1- all the animation layers was rendered from TOONBOOM as .SWF to keep it in vector for compositing issue.
Flash allows to tinker with the Quality output and to activate Deblocking and Compression Algorithm, but it is definitively no lossless format. Don`t know anything about the export options of toonboom. Also: when scaling vector based content there are 4 different settings for outlines that can get messy to handle when imported in other programms, so it comes with caveats.