Keep losing video

Sorry if this sounds stupid but I am new to FCPX and I am putting together a tutorial but now every time I make even the smallest change on my timeline I completely lose video in my viewer. I can still hear everything but my viewer goes black. I restart fcpx and I have video back but then as soon as I make another change it goes away again.

Can anyone help me please?

I have not really heard of that problem before. You might make sure you have the latest FCPX update (10.0.2) and your OS is also updated. Perhaps if you let us know what OS you're using and what you imported into your event for the project we might have other ideas.

I experienced a blank viewer when I tried working with imported AVCHD video on my Mac Book Air.

Do you make a screen recording for your tutorial? This may use up all your resources and FCP X can't "breathe". Just a guess.

On a MB Air you have just barely enough power for FCP X and Motion 5. In fact Motion 5 will just roll over dead on an Air. Be sure the AVCHD files are converted to ProRes Proxies (no need to Optimize, just make proxies) for editing with. I always recommend Air users to edit with Proxies to get maximum performance.

Use Command-comma to open the Preferences.
Editing tab, turn off "Show Reference Waveforms".
Playback tab, turn off "Background Rendering" until you're done.
Set "Playback" to "User Proxy Media" until you're totally finished.
Turn Playback to "Use original or optimized media" only when you're ready to do an export.
Turn off "Warn when dropping frames on playback".
Import tab, be sure "Create proxy media" is checked.

You'll not Optimize on import, but do make proxie media. Edit with that. When you switch back to original media for playback, FCP X will stop pointing to the proxie media which is easier for an Air to handle, and point to the original files for exporting full res output.

And yes, FCP X can max out the resources of an Air's CPU and GPU easily. But with these settings, you can minimize that and get the best performance out of FCP X on an Air. A T'bolt drive on an Air would also make a huge difference.

Thanks Ben those are handy tips although I do not seriously use FCP X on my Mac Book Air. I tried it just out of curiousity. But for simple stuff and using your tips its actually quite usable. Unfortunately no Thunderbold here, I have last years Air.

I'm pretty sure the thread starter also maxes out his computer by recording a FCP X tutorial screencast. Your tipps should also serve him well.

FCP X alone will max out and Air's grahpics card, running something like ScreenFlow at the same time is really pushing an Air to it's limits.

I am using an iMac 3.4 Ghz i7 with 16 GB of Ram.
The video is mostly AVCHD and is coming from an external HD through firewire.

I have all the updates that you referenced. Could it be because I am running the video from an external HD? Everyone kept telling me not to run the edits from my main drive. Again i am new to this so my questions will probably sound pretty basic to you guys, sorry.

Not doing a screen recording, just using imported AVCHD like you mentioned. Will try the steps put out by BenB and see if that fixes the problem.

Are you "Optimizing" the AVCHD footage? If not, you really should be. And the drive must be a 7200rpm FW700 drive, too. What is the capacity of the FW drive, and how much of it is unused? Can we confirm all of this?

Yes, you should never use your system drive for serious editing.

i have been Optimizing the video but not using a proxy.
Can't find any information regarding the rpm but the external is hooked up through firewire 800.
It is a 1 TB and only has about 350 GB on it right now.

What is the make and model of the FW800 drive? We can look it up.

1000 x .15 = 150MB, so you're good on free space, you have a whole 200-250MB to play with there before you need to worry.

Proxy will eat up more drive space, making a low res (but very good visual quality for editing with) copy of the file. But it will reduce the strain on an laptop or iMac. So you do need the drive space to do it.

Iomega
eGo
Desktop Hard Drive
Mac Edition
model # RDHD-C2

So I finally figured it out! Somehow one of my voice over clips jumped up into the timeline with the video. I missed it because it was blended in together but that is what was making my video drop out. I pulled the voice over back down and it worked fine. Just FYI in case this happens to someone else.

Glad you got it sorted out! Sometimes the solution is right there in front of you!

Yes, that is a 7200rpm drive.