OK, I wanted to look at some quicktime movie trailers from ComingSoon.net. As a sample, we'll try the QuickTime trailer from Johnson Family Vacation. With my standard mplayer installation I got picture but no sound, though I get sound with other QuickTime files, notably this King Arthur teaser. Running mplayer from the command line e.g.,
$ mplayer http://images.hollywood.com/images/quicktime/johnsonfamily_fox_t_low.mov
gives a line which says something like:
qtmlClient.dll not found.
Looking around the web for information on dll files in mplayer, I found that they are to be found in /usr/lib/win32, which doesn't exist on my system. Searching through Google I eventually found several mplayer dll rpm files at RPMfind.net, but the first ones I tried didn't have qtmlClient.dll. Eventually I went to the Mplayer Home Page, where I found a set of binary Codecs. I first downloaded the Latest Win32 Codec pack, and put the contents into /usr/lib/win32, but that still didn't have qtmlClient.dll. That file turns out to be in the All in One (aka essential)) package. I loaded qtmlClient.dll into /usr/lib/win32, and now I get sound with the movie.
There are some library files in the "essential" package, and I'm not exactly sure where they should go, so for now I'm leaving them out of the picture. At least, mplayer works for a new set of QuickTime files.
Note: further Googling shows that the essential package exists as an RPM. I may eventually rip out my own installation and put in the RPMs.