[Swfdec] Can't use Mozilla plugin or play video with 0.8.2 / 0.9.2

[Jesse Zbikowski]

Hi, I built the 0.8.2 and 0.9.2 source tarballs but I can't view Flash
content in Firefox.  In about:plugins I see:

Shockwave Flash

    File name: libswfdecmozilla.so
    Shockwave Flash 9.0 r999

MIME Type 	Description 	Suffixes 	Enabled
application/x-shockwave-flash 	Adobe Flash movie 	swf 	Yes
application/futuresplash 	FutureSplash movie 	spl 	Yes

but on YouTube, etc. I don't see a player.  I can get the URL of the
SWF and run it with swfplay from the command line, e.g.

swfplay http://s.ytimg.com/yt/swf/watch-vfl65425.swf

This gives me a player window with play button, volume control, etc.
but it shows 0:00/0:00 with a black rectangle (no video) and pegs the
CPU.  I can also use swfplay for the Mario Rush game listed on the
Screenshots page, which works somewhat but also pegs the CPU and is
too slow to actually use (after a few seconds I start losing lots of
frames).  The same game works mostly OK with the official Adobe Flash
10 player on my computer (occasional CPU spikes but playable).  My
system is Ubuntu 8.10 Intrepid Ibex with Firefox 3.0.4, 3GHz Mobile
Intel Pentium 4 CPU, and 1GB RAM.  I would appreciate it if someone
could offer troubleshooting advice on how I can watch YouTube videos
either in the browser or standalone.

Thanks in advance,
Jesse Z.