len at ovenwerks.net
Wed Jun 5 13:46:26 UTC 2013
On Wed, June 5, 2013 12:32 am, Jimmy Sjölund wrote:
> On Tue, Jun 4, 2013 at 11:01 PM, Hartmut Noack
> <zettberlin at linuxuse.de>wrote:
>> > 4) I have sync all the videos to the music file. To do this in Mac or
>> > Windows the video editor often support scrubbing, so you can pinpoint
>> > audio in the current video with the same spot in the song. Kdenlive
>> > not support scrubbing so I have to look for obvious things in the
>> > like certain words sung or when an instrument start to play.
>> Just orientate by the waveforms and you get it perfectly in sync. Since
>> your videoclips are shot at the very recording you can align the audio
>> of the videoclip and the mixed-down song just perfectly...
>> That is what I do at first to get it narrowed down, but unfortunately my
> experience is that the waveforms that are displayed are not accurate
> and I need to nudge a couple (or sometimes even more) frames forward or
> backwards to get it to sync perfectly. This I can do either visually or
> when I let both audio sound at the same time. Any delay in between them
> means they are not in sync even though the waveforms are. But that is most
> likely a discussion I should bring up with the Kdenlive people.
I would assume you are using more than one camera if you are taking shots
of different instruments all in one take. Unless they are all the same
make and model of camera, the sync from audio to video may be different
from camera to camera. A visual cue such as a strobe may be a better tool
Also pay attention to frame rate, though I would guess that if you are
happy with things once they are synced this is ok. Different frame rates
would of course make sync wander from one end of a video to the other.
I expect that on a very long video you would loose sync towards the end
anyway as your cameras are not running from a master clock. In TV
broadcast situations all video sources get their sync from one master
clock through the same length of cable round trip to the switcher, this
includes cameras, VCRs, telecine, and titling/animation. Off site video is
framestored so it can be synced to station... kind of like resampling.
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