When I tried watch the recent Mars landing with an old script I found that NASA had changed the sources and old scripts didn't work anymore. I put together a collection of feeds that currently work into a script to make finding NASA feeds easier and the best quality I could find.
Some feeds are HD. Those that are in HD resolution the bandwidth is relatively low for HD resolution leading to temporarily reduced picture quality.
Not all feeds are active 24/7. Some are only active when an event is happening at that feed's center or facility. When offline, some centers will have repeating clips, like YouTube, while others will have a blank screen or fixed logo.
The compilation is as complete as I could make it. If you find more feeds let me know and I'll add those in updates.
I did not include iOS or Android specific feeds ( available at http://www.nasa.gov/multimedia/nasatv/ )
Finally, I couldn't have done this without ScriptMaker - Thanks Jeromy!
"Share and Enjoy"
Now, the small print... Note: NASA and USTREAM retain the control of these feeds and their content. NASA, USTREAM, Apple (iOS), Google (Android, YouTube) retain all rights to their respective marks and they are used here for information only.