IMovie 9 - imported movie shows black in preview pane

Question

Hey everyone, first time posting here.
Here's my issue. I have been working on a project for over a week now and have imported over 30 big files without any problems. Once I imported a file, I would select the footage I needed and add the selections to the top left window for editing. Everytime I would add new selections to my project, I would edit and preview in the top right pane without any problems. But since yesterday, none of my footage is viewable in the preview AND the event panes. In other words, everything I have imported/selected/edited is there, but it's all black (I can't say for audio, 'cause it's a silent movie). However, in the project (top left) pane, all of my thumbnails show the image (not black) and I can even see that the footage is there and working when I hit the spacebar. I have tried exporting the movie to see if it was just a problem with my preview and event panes, but the exported movie also shows everything black. There are text frame and pictures in my project, and these show just fine.
All of the imported files are in the Movie/iMovie Events/"Title of event" folder with a .mov extension.
Help!? (keep in mind that I'm somewhat of a newbie to this. I'm not an incompetent, but definitely not a IT wizard... )

Answer 1

I am guessing that these are big files that have been converted from something, maybe VHS or 8MM tape. If they were DV or HD from a modern camcorder, they would split into short clips naturally. Let me know if I am on the right track.
OK there are three ways to do this depending on what you are after.
1) Option 1, get the three minutes I need into iMovie right now, and worry about the rest later
2) Option 2, get all the clips into iMovie right now. I'll pick the 3 minutes later
3) Option 3, Split all the clips into shorter clips so I can put them into real logical events. In other words, you have an hour long clip from a VHS tape, but you want to split it into the logical events that are contained in the clip.
Option 1)
There is a free tool called MPEG Streamclip. Download it here. The Beta version is very stable, so I recommend that. http://www.squared5.com/svideo/mpeg-streamclip-mac.html
Close iMovie.
Go to the Finder. Find your iMovie Events folder. I am assuming that your 17 hours of footage are on an external hard drive, so they would be in the iMovie Events/"your event name" folder at the top level of the drive. If they are still on your internal drive, they are in the Movies/iMovie Events/"your event name" folder.
Drag the first long clip into MPEG Streamclip. Move the playhead to the start of the bit that you need from this clip, and press i for in point. Then move the playhead to the end of the bit that you need and press o for out point.
Finally, use FILE/EXPORT TO QUICKTIME to export it out in the same format it currently is. Or better yet, export it out as Apple Intermediate Codec.  HOWEVER, if your large files are DV, you will want to keep them as DV. You can do this by using FILE/EXPORT TO DV.  This will give you a short clip of just what you need. Repeat this for all your 30 clips. Then import these short clips into an Event in iMovie, using FILE/IMPORT MOVIES.
Also, in this option, I would move the original event file (the huge one) to another folder on the same drive. For example call it "Original clips". This way, iMovie will not think it is an event, and will choke on trying to load it.
Option 2)
Close iMovie.
Go to the Finder. Find your iMovie Events folder. I am assuming that your 17 hours of footage are on an external hard drive, so they would be in the iMovie Events/"your event name" folder at the top level of the drive. If they are still on your internal drive, they are in the Movies/iMovie Events/"your event name" folder.
You will want to make 30 (or so) new folders within the iMovie Events folder. Give them each a name of your choice, for example call them Tape 1, Tape 2, etc. Anything that makes sense to you.
Now go back to the original folder that contains the 30 big clips. You will want to move each of these into one of these new folders by dragging.
The only thing left in the old folder should be some folders called Cache, Thumbnails, and maybe Analysis. You can move these to the trash.
Now restart iMovie. iMovie should see these new Events and start creating thumbnails. This could take a while. Let it run. Now you can edit.
Option 3)
You will use MPEG Streamclip, just as in option 1, but now, instead of just picking out the portion you will use immediately, you will position the playhead to the beginning of a logical clip and press i, then move the playhead to the ending of the logical clip, and press o. Then use FILE/EXPORT TO DV or FILE/EXPORT TO QUICKTIME and repeat until you have them all. Your logical clips could either be at the Event level. (You would set the in point and the beginning of the Christmas footage, and then set the out point where the Christmas footage ends.) Or they could be individual scenes within the logical event. It can be anything your want.  To use another example, if your 17 hours of footage was of football games, you could set the in and out points corresponding to the quarter of the game, or you could set them for each play. Whatever will make it easier for you later.
Finally, in option 3, you have an opportunity to name your clips so they will be easy to find, and so they will automatically be placed into the right year in the Event Library. As you name each clip, give it a name in this format:
clip-yyyy-mm-dd hh;mm;ss.ext
where clip must be lower case
hh is hours in 24 hour time
ext is the current extension (e.g. mov or dv). MPEG Streamclip should assign this automatically according to your settings.
You should now have separated all the clips from this one large clip. You can place them in logical event folders within the iMovie Events folder. For example, Christmas 1960, or Football Homecoming Game, whatever makes sense.
Now do the second large clip the same way, until all are done.
Restart iMovie and it will generate thumbnails.
That gets us through the three options.
I would strongly recommend that whichever option you choose, you do a test of it all the way through your workflow so that you understand it before doing all 17 hours of footage.
I wrote this quickly so it may be hard to follow. Do not hesitate to ask questions if something is not making sense.