Hello everyone,
For the first time, I’ve encountered a strange problem with Adobe After Effects CS4. I’m currently trying to sync up my animation to audio and such which requires RAM Previewing to see the results.
When I RAM Preview the certain section I’m working on, everything syncs up well. After I finish the section I’m on, I RAM Preview the whole project to see what it looks like fully. All of a sudden, only the beginning of my projects are in sync and the middle/end are not.
After many experiments, it seems like only the first 10 sec of my “Work Area Region” is syncing correctly, anything after, either the audio is lagging behind or my animation starts lagging. It’s NOT a frame rate problem, the animation is playing 29.976 (Real Time) all the way, I checked. Perhaps a CPU or RAM issues?
Any suggestions? Thanks guys! 
If it’s an mp3, use a wav or something that’s not compressed.
Otherwise it might just be down to After Effects. There are various things that happen differently with audio between preview and render. For instance, I’ve often found that you can create a perfect cross-fade between two parts of a track on the timeline and when you render it out there’s an audible peak or a drop in the volume at that point.
After Effects is famously not that good for working with audio. But I’ve never had major synch problems… at least not with aiff / wav.
-f.
Totally agree with felt.
You could also try pre-composing the audio layer. Don’t know why (I think I read about it at Creative Cow) but it has helped me, esp. when, for example, cross-fading or applying effects to audio.
I was searching for a similar issue a while back, i found my answer in this forum thread http://forums.creativecow.net/thread/2/963950
Good luck with it
felt_tips said
If it’s an mp3, use a wav or something that’s not compressed.
Otherwise it might just be down to After Effects. There are various things that happen differently with audio between preview and render. For instance, I’ve often found that you can create a perfect cross-fade between two parts of a track on the timeline and when you render it out there’s an audible peak or a drop in the volume at that point.
-f.
You hear a peak drop because the crossfade is linear, one way arround it is to make the crossfade and then use the keyframe assistant/exponential scale on the audio level keyframes to get a nice curve. It’s not perfect but definitely less noticeable
@sonora.
I get that, decibels is a logarithmic scale, so requires a logarithmic cross fade. The question is: why does it sound different in the preview to the render?
@generator.
I’ll give that trick a try.
-f.
Thanks for all the help and tips guys!