Lousy iMovie HD 6.0.2 playback -- stuttering video and audio

Thanks for all the suggestions. I will try them, one at a time! ...and report back.

I tried the above suggestions, one at a time, but the end result hasn't changed.
1) First, I moved LaCieBackup utility (& its associated Application support) to Trash, restarted the computer, opened iMovie, and played my movie but it was still jerky, with poor (buzzing) sound. I took out LaCie first because it had been generating a lot of activity in the Console screen, every minute or two, a message "...couldn't register hotkey....". I've never used LaCie Backup.
2) Next, I did the same with Flip4Mac (although it didn't appear in Activity Monitor) ....restarted etc. ...same result (no improvement).
3) I exported a 10 minute selection to QuickTime (the entire movie would have taken too long). This didn't change iMovie's poor performance, but the QT movie played fine (motion & sound OK).

I had set iMovie's preferences for playback so Quality was "Standard" (the lowest) and unchecked the box re keeping playhead centered.

I have also frequently Save'd my project to help keep things "clean", but that makes no difference to the overall performance.

I haven't emptied iMovie's trash. There's 5.41 GB in there. I don't want to empty it because I'm still editing, have lots more to do, and want to be able to restore any clips if needed.

At various times, I watched the Activity Monitor. Whenever I was playing back iMovie, the little graph was completely filled with vertical bars. The CPU usage for iMovie fluctuated between 40%-160%. Real memory ranged from less than 100 MB to over 480 MB, while virtual memory was about twice that. I wonder if this is the problem.... doesn't virtual memory entail constant hard-drive accesses? __ I didn't notice any other processes hogging as much resources as iMovie. There were close to 20 active processes displayed, most of which I have no idea what they're for.

I have 1GB of RAM, composed of 4 x 256MB DDR SDRAMs (PC3200U-30330). All are 'OK' according to System Profiler.

I wonder if more RAM would solve my problem? ________

G5/1.8GHz SP 80GB Mac OS X (10.4.6) 1GB RAM, +300G internal, 4 external FW HD's

Thanks, Adam

The 80G and 300G are both internal drives. They have 48G and 108G to spare, respectively. (the 80G drive is the system drive; my current movie projects are on the 300G drive). I have also tried working with projects on an external FW800 drive, but encountered the same problem of stuttering.

I see I'm not alone with this problem. Unfortunately, I don't have iMovie5 (I see, in this & other threads, that others have returned back to 5 from 6, for various reasons). I went from version 3 (on a G4) -- which worked fine, but couldn't handle widescreen 16:9 video -- to version 6 on this G5. Version 6 definitely has some serious problems, otherwise I quite like it.

Although extra RAM may improve some things, I doubt it's the cure for this because I was able to work very well with projects even larger (longer) than this one under iMovie3 on a G4/450 with only 640MB of RAM. It was slower rendering transitions & titles, and couldn't handle 16:9 which I'm using now.

I'll keep watching this thread, because I really can't continue very well with this problem. I haven't talked to Apple directly. I wonder how aware they are of this issue.

G5/1.8GHz SP 80GB Mac OS X (10.4.6) 1GB RAM, +300G internal, 4 external FW HD's

Hi Texas...

I don't think my movie is too complicated for iMovie. It's much longer than yours (final product will be just under an hour), but it's basically a serial string of clips, with cross dissolve being the most common transition. I usually extract the audio from each pair of clips that dissolve together, so that I have better control over the fade-out and overlapping fade-in of the live sound. I do have some music tracks added which I fade in & out where I fade out & in the live audio. I have some basic titles at the beginning, some subtitles on various clips (this is a travel video), and plan to have scrolling credit titles at the end. Nothing too out of the ordinary.

I've created a couple of dozen videos like this before using iMovie3 on a G4/450MHz 640MB PowerPC with no problems like this. (I switched to iMovie6 on a G5/1.8GHz 1GB RAM so I could do widescreen 16:9 editing and DVD burning). iMovie should be able to handle what I'm doing. Otherwise, there must be thousands of users out there having the same problems I am.

FCE is increasingly tempting, as this problem is really holding me up. I've got two other movie projects waiting to be edited which are now several months behind.

By the way, I've done a couple of test exports to QuickTime of a span of selected clips (which include several cross dissolves and overlapping sound etc.) from this movie and they play perfectly well in QT7. The problem is definitely to do with iMovie6.

Thanks for your feedback! Hope one of us finds a solution ...soon!

A thought just struck me: while I don't think additional RAM will fix it (I currently have 4x256MB), I wonder if it could have anything to do with the video card. Mine is a GeForce FX 5200. What does everybody else have, who are experiencing this problem?? ______ Naw, I doubt that's the problem... I can playback any DVD without any problems on this machine.

A little more on this iMovie problem...

Sometimes, just scrolling up & down the Clips pane can be a challenge. When sliding the 'elevator' up/down, it doesn't always respond immediately ...may have to wait a few seconds before it does. I've learned that if i just wait patiently for a half minute or so, to let something (I don't know what!) "settle down", then it will scroll more smoothly. This tactic doesn't help with editing in Timeline however.

Another little discovery...
(Background note: I don't drag my clips from the Clip Pane to ClipViewer line. Instead, I Copy & Paste them, because I want to keep the 'originals' in the pane in case I really mess up and need to start editing any particular clip all over again). My discovery is.... that if I select (one or more) clips in the Timeline or ClipViewer, it plays back very poorly -- so choppy that the audio is barely intelligible, and the video motion starts/skips/stops in a very jerky fashion. BUT, if I select the same clip(s) in the Clips Pane, and play them back, they play smoothly. I wonder if this will help to narrow down the problem.... It's mainly in the ClipViewer or Timeline.

I'm really at a loss as to what's causing this. And totally frustrated, as I cannot continue with my editing. It's impossible to work this way. iMovie6 is badly flawed. There should be no need to buy Final Cut just to get around this problem.

G5/1.8GHz SP 80GB Mac OS X (10.4.6) 1GB RAM, +300G internal, 5 external FW HD's