Best way to speed up clips beyond 4x?

Andy C wrote on 8/30/2010, 1:03 PM

I'm trying to speed up a one-hour 'time-lapse' AVCHD clip to 1 minute. Unfortunately VMS will only go up to 4 times the original speed. I've tried speeding up, rendering, speeding up, rendering, etc. until I got 64x but with each render I lost quality (as you might expect). Anyone got any better ideas how to do this?

Comments

musicvid10 wrote on 8/30/2010, 1:50 PM

Look about 25 posts down.

Andy C wrote on 8/31/2010, 12:30 AM

Thanks, I see it. I always search before I post so I'm not sure why my search terms didn't pick that one up.
Anyway, looks like VMS is stuck at 4x so I see no alternative to my current method. Anyone know of any 3rd party tools? I'd normally use something like VirtualDub but I don't think that handles AVCHD.

TOG62 wrote on 8/31/2010, 3:13 AM

Would it not be easier to take evenly-spaced snapshots from the video, say 30 per minute and use these to replace the original footage? In effect, this would be time-lapse photography.

Andy C wrote on 8/31/2010, 4:46 AM

Yes, happy to do that, but that's a heck of a lot of work - or is there an automated way to do it?

JayLJohnston wrote on 8/31/2010, 10:03 AM

Hey Andy, I'm the one who started that other thread. I haven't noticed quality loss (or much) when rendering in "Best" quality. I first started doing this in the default "Good" quality and noticed loss, but then learned about changing it. My videos look pretty awesome this way, and the first time rendering is the only one that seems to take a long time to finish.

Andy C wrote on 9/1/2010, 3:07 AM

Hi Jay, I too am using the 'Best' quality. The problem is that it's a time lapse of the moon coming up at dusk and therefore the contrast is very high between the moon and night sky. After the third render I get a halo effect moving in concentric cirlcles around the moon. It's as if some of the intermediate bands of grey scale have got lost in the repeated processing.
I use Sony the AVC codec on best quality. What intermediate render format are you using?

JayLJohnston wrote on 9/1/2010, 8:43 AM

ahh, maybe the low light is what's causing issues with speeding up. I'm speeding up cruise ships spinning around and moving during the daytime. I am rendering to .m2t (I think) format and will eventually be creating DVDs and blurays from it. There very well may be some signal degradation, but if there is, then it's not a whole lot, but again, it might be because I'm shooting just in the daytime.