WMV in Quicktime ánd QuickLook

I can't preview complete .WMV files in QuickLook, it only shows the first 5% (or so) of the video. And to watch a .WMV file in QuickTime (Pro, 7.6.6) it needs to first 'import' the whole file which can literally take minutes depending on the file's size. The strange is however, that in VLC I can open and instantly watch the same .WMV files that QuickTime needs to import.

QT 7 is based on "old" program stream video technology which requires QT to pre-expand the data to locate the end of the file and ensure that it is properly terminated. This process does take time but can be avoided thereafter if you simply use the "Save As..." option to save the expanded data to an MOV file container which can then open immediately but is proably twice the size of the original WMV file container. (You can think of this as a string of railroad cars. In the WMV file container, QT must read through the data in every car to get from the engine to the caboose while in an MOV file container, QT just looks at each railroad car and jumps to the next car without having to actually read the data inside each car—a much faster operation.)

I'm running the latest version of OSX Lion: 10.7.4 with the Flip4Mac Windows Media Components for QuickTime. But this problem has been around for a few years actually. I think it changed at some point, either updating the OS or installing a newer version of Flip4Mac.

One of the major changes in QT X "new" technology is that it is more transport stream friendly.

I'm guessing that VLC is using a different codec or way of playing back WMV files. I'd just like QuickTime Pro to do the same thing; instantly open and play any .WMV file.

VLC does not rely on QT technology at all. It employs its own built in codec support which targets both program and transport streams using open source routines developed over the years since 1996 while Apple has only recently turned its eye in this direction with the advent of QT X.

What I'm wondering is, it seems Finder's Preview function shows me the .wmv files using QT 7's 'engine', would it be possible to somehow get Preview to instead use QT X (+ Flip4Mac ?) so that it can immediatly show me the full file?

The "preview" function is based on "QuickView" technology (about which I know nothing)—not QT technology.

(At the moment I don't have Flip4Mac installed for QT X it seems, as the program won't open .wmv files.)

Not a regular WMV user so I had to locate a WMV file to test lastest Flip4Mac software update. I see what you mean about the lastest changes. Original source file opens and auto plays with "black" screen and no audio in QT X Player. But, if I export the source file to "WMV" in QT X Player, then the newly exported WMV file plays correctly in QT X Player with both audio and video. On the other hand, if I open source file in the QT 7 Player, and save it in an MOV file container and play it in the QT X Player, then the video plays but there is still no audio. Oddly enough, the QT 7 Player plays the original source file, the QT X exported WMV file, and the QT 7 MOV file corretly with both audio and video. Very strange indeed.