Topic: sync'ing external audio to videos from a digital camera?

[junkyardt]

anyone ever tried this? some guy sent me a bunch of videos he took on what he says was a 'Canon point-and-shoot'. the video quality is decent and is the only video i know of from the show (which is why i'm bothering) but the audio is absolutely horrible/unlistenable. i was at the show rolling audio so i thought i'd splice in my good audio real quick in Vegas for him and send the videos back. i didn't think it would be hard, but i'm having major trouble with it.

previously i've only ever sync'ed audio into my videos, which are all MiniDV sourced. that's always been easy -- line up the beginning, jump to the end, stretch the audio to be in sync at the end, done. maybe tweak a little from there, but it usually only takes a few minutes. however, that process isn't working with these videos from his digital camera. i line it up at the beginning and stretch to be in sync at the end, but then it's out of sync at the beginning again. it does this every time. no matter whether i try moving the video in either direction along the timeline, or stretching the external audio in either direction, it is always out of sync at either the beginning or end. i cannot get the whole thing in sync. and he only shot some select songs, so we're just talking one song at a time, not even the full show. i have never had anywhere near this much trouble working with MiniDV video.

any thoughts? is there something about the nature of the way digital cameras record video that is significantly different from how camcorders do? like their internal clocks don't have a constant speed or something? i'm pretty much stumped at this point.

[beatkilla]

What are the properties of the video?i have some files from a canon point and shoot 720p .mov that i synched up audio to in vegas with no issues.if you synch the drum stick count off of a song jump ahead in the timeline every 3 to 5 minutes.how long before you notice a problem?and is your audio ahead now or the point and shoot?

[Shadow_7]

Drums and/or audience applause are good sync points.  It really depends on how many sync points you're going to do, and how much you need to adjust the speed to compensate for the clocks.  Several threads on the subject in these forums already.  I generally look at the waveform in audacity and find the edit point(s).  Which assumes that the camera audio has at least one good segment that's syncable.  Otherwise basing your choice on 1/30th of second (video frames) versus 1/48000 samples (audio) a second is a bit hit and miss.  Especially for music stuff where you can tell if the drums are delayed or worse preceding the visual element.  But not enough to apply a +/- number to it.

And without two relatively distant sync points to determine drift, you might find yourself doing a lot of strange edits to maintain sync over a duration.  Hopefully a) more audio than video, and b) something meaningful date/time stamp wise and/or audio wise IN the video element.

[shoestringconcerts]

i have seen these problems when mixing multiple digital camera angles but i just resynched scene by scene as needed

i would assume you are using the hold down shift button funtion at the edge of the audio to either stretch it or compact it.  I have never heard of what you are talking about happening.

if you post megaupload links to video and audio clips i would play with it

[stantheman1976]

If the audio is a compressed VBR format maybe that is causing the issue.  I've never had issues syncing any kind of sources as long as they were digital.  You need to find out what kind of camera he has and what kind of audio/video it records.