You have Found one of the biggest issues with streaming Video It does look mushy @ full screen unless you sit a few feet away Only improvements are make sure the Video Graphics card driver is up to dats (have many built in Fixes and little tweaks) also the Java ,Flash and DirectX drivers are not several versions out . And last but not least, your screen resolution is not set to anything under 1024x768 and the colour level is (Highest)32 Bit
If just one of those settings is out it will spoil your viewing .I'd look in there first then move onto the Drivers later
-------------------- History so far.. 9 years surfing & 28 Years Computing (First ZX81 1k)