Quicktime X will not play some Apple Mpeg 4 Movie Files

Question

Hi,
Having a strange issue.  Quicktime X will not play some of my Apple Mpeg 4 Movie files anymore.
The files open fine in Quicktime 7, but not Quicktime X. 
I receive the error message "The document could not be opened. A required Codec is not available"
I have installed other codecs (Flip4Mac as well as Perian), but no luck.  Have re-installed Quicktime X (10.1) and software is all up to date (running Lion 10.7.2).  The movie file works fine if I import it to iTunes as well.
Called AppleCare Support and they could not come up with an solution.  Does anyone here have any ideas?
Thanks!

Answer 1

(BTW, I just realized this was an MPEG-4 topic - my issue wasn't necessairly centered around that architecture)
Yes, I naturally assumed that you were having problems at some point with MPEG-4 Part 2 or Part 10 content.
Since I mentioned "from," I should have mentioned what the codec/wrapper was (it was captured into a .mov file using DV/NTSC via "Capture Now" in Final Cut Pro studio V7, via an analog-to-digital converter).  What makes this confusing is that files captured with the same settings sometimes open right into QuickTime X with their audio/video intact, and at other times, only the audio shows up (where upon opening that same file in QT 7, we can see both audio and video). Interestingly, the problem files icon shows up on the desktop as the generic movie icon, whereas the "normal" files' icon is the first frame of the video.
May we assume at this point that the source video data is DV-25 with 16-bit Interger (Linear PCM) audio sampled at 48.0 KHz and it is the scratch MOV file that may or may not open/play correctly in QT X but always opens correctly in QT 7?
Ultimately, though, this is an unimportant point in solving my issue. Why? Well, if I can successfully open the problem files in Compressor (e.g., see/hear the video/audio), then I can theoretically re-compress (or "re-wrap?") them to whatever codec I want - ideally one 100% compatible with QuickTime X.
I took a test file, placed it into Compressor, and applied the DV/NTSC setting to it (yes, I know, the same setting the file already had). After re-encoding (which took very little time), the file was perfectly executable in QuickTime X - both Audio and video showing as to be expected, and no real difference in quality (not that VHS source is quality to begin with).
This sounds as if the "problem" file's container may be the source of the problem. As I don't know if your Compressor test is passing the data through to a new faile container, I would make an additional test here. If your version of QT 7 is keyed for pro use, I would simply use the "Save As..." File menu option to to create a new file container. In fact, I would probably just create a "reference" file rather than another "standalone" file here—a very, very fast operation—and then open the secondary file in the QT 7 "Properties" window to ensure all of the data tracks (1 video, 2 audio, and 1 timing) are present. If all looks good, I would then try opening the reference file in QT X to see it it now plays. (I.e., whether you use a reference file here or a standalone file, the object is to see if the QT X player will now recognize all contained data tracks whether resourced by reference or physically contained in/via the new wrapper.)
Could this have been answered without knowing the complete "from" specs? Probably… which is why I posted to the help forum in the first place - the goal being some other reader may have had the same issue, and had a handy solution or suggestion, saving me the time of experimentation (what forums are great for).
I don't know about you, but I would still be looking at profile/level combination settings to see if an an assumed MPEG-4/AVC video and/or AAC audio settings had been properly encoded for QT playback.
I have no doubt that there's a technical difference between the files that created this issue in the first place. But, the solution of re-compressing with an identical codec did the trick, which for this project is good enough for me.
Recompressing data is slower than rewrapping data which is slower than rereferencing the data pointers. But, if your solution works, then that is all that matters.