How are you viewing them? In what way are they poor quality? What version of InDesign are you using? What video format did you pick?
I'm having the same issue as above. I'm using the current versions of InDesign CC and Acrobat DC.
The video format I'm using is H.264 MP4 -- I also tried converting that to FLV, but the quality was even worse. Where the MP4 comes out grainy and uneven, the FLV is utterly pixelated.
Normal elements of the document have no quality issues,only the video. The only resolution controls I've come across in creating the interactive PDF are those for the document resolution, but the video quality appears to be unaffected by changes there.