Fortunately, there is a fix. At least there was for me. Due to a problem with newer versions of Adobe Flash Player on my Win XP desktop PC, I have been unable to update beyond Flash Player version 10.3. When I tried to update to version 11.x, the audio of all streaming video would "stutter" badly, making the audio unlistenable in Firefox and Opera. Chrome doesn't give you an option. It updates itself whether you want it to or not (one reason I don't use Chrome). The Flash problem manifested itself in Chrome when Flash 11 was installed. The ActiveX Flash 11.x in Internet Explorer, for some reason, didn't have the same problem, but IE is not my browser of choice by a long shot.
Fortuitously, Adobe released version 11.9 just a few days ago on December 10th. The release notes mentioned fixes to audio quality problems, do I decided to give it a try. I let Chrome update itself, which took me from Flash 11.6 to 11.9 and Voila! I could view JTV channels again AND the stuttering problem went away. Emboldened, I downloaded and installed 11.9 for use by Firefox and Opera. Lo and behold, I got the same result: no stuttering and JTV channels viewable again.
So, if anyone is having the problems I described, check your Flash and upgrade to 11.9 if you aren't already on that version. (Right-click on a Flash window, even the one that says "Loading channel data", and it will show you your Flash version.) Hopefully, that will fix you up.