Extracted audio caused distortion in video timing

Question

i need help!
i am making a music video for class.
from the edit menu i chose select all and then extracted audio, so that I could go in individually to each clip and delete the audio i did not need. when i tried to do a test delete and played the clip back the audio was gone like i wanted, but the song and the video were totally out of sync and my computer froze up and just played a bleep of sound here and showed a random clip there.
it took forever to unfreeze. it is still out of sync even after restarting my computer. the audio is still extracted from all the clips but the video and audio are still totally out of sync. I'm thinking if I could just unextract all the audio or revert it back to the original...that would solve the problem, but it will not let me do so?
some of the audio files are still available in my trash including audio for the whole video.
any suggestions?

Answer 1

Welcome to iMovie Discussions.
'Extracting' audio just copies it and puts it in an audio track underneath the video, and then silences the original sound within the video clip. So it does two jobs, instead of just silencing the audio.
To silence audio within a clip, just click on the little clock, at lower left, to show the full Timeline view, and then in the Menu at the top of the screen use 'View' and 'Show Clip Volume Levels'. You can then select a clip, and click on the little loudspeaker icon, alongside the volume level "Clip: 100%".
Your audio going out of sync sounds more like iMovie 4 rather than iMovie5/HD. But if your hard disc is close to being full on the iBook, that can cause problems for iMovie.
To fix things, you could try the following:
(1) As your audio should now be in separate audio clips beneath the video, you should be able to click on and then slide ('drag') your audio clips to line them up with the appropriate video, then use Apple+'L' to Lock the audio to the relevant video.
(2) As all the original audio remains within the video clips, but it's just had its volume reduced to zero during the 'Extraction', you could select the video clips, and return their volume up to 100% with that little volume slider at the bottom of the screen. When you've done that, UN-TICK (un-check) the little boxes at the extreme right which switches on or off the sound from the audio track(s), so that only the video track is ticked, and try playing the video: all the audio should now be back. If that plays OK, you can then just delete all the separate audio in the track(s) beneath, then Save your project. Then re-tick (check) the audio track boxes again, so that they're not disabled.
The original audio should now be restored, and you can do what you like with it. But it's always better to just reduce to zero any sound you don't want, rather than duplicating it - by 'Extracting' - and then just silencing the original ..and possibly the duplicate. That doubles the work which your Mac has to do during playback ..as it has to keep looking for the separate audio instructions, in its master project file, as well as playing back the video.
So (a) make sure that you've LOTS of spare space on your iBook, and (b) don't strain it too much by giving it too much to do, and (c) things may go smoother if you keep your video projects on a separate, fast (5400rpm or faster) FireWire hard disc (formatted as 'Mac OS Extended' or 'HFS+') plugged in to the iBook, rather than on the iBook's internal disc, and (d) make sure that you have no other programs running when you're editing with iMovie ..as iMovie needs as much of the Mac's attention as possible, and may be sluggish on a slow Mac if there are other programs running.
Hope this helps..