[LAU] SMPTE timecode?

Florian Faber faber at faberman.de
Thu Feb 18 12:24:43 EST 2010


Rick,

>    I've been told by a local friend that it's not worth the trouble.  Video 
> is approx 30 FPS, and audio is 48k S/s, so alignment 'by ear' is 'good 
> enough'.  That may be what they're planning to do anyway...

If you have a drift between video clock and your sample word clock of as
little as 0.01%, it means you have an offset of 360ms (or ~11 frames)
per hour. Which you can only 'fix' by src, and you don't want that.

Just to give you an impression how bad it really can be: In real life I
have encountered word clocks ranging from 47981Hz (=-0.03%) to 48041Hz
(=+0.08%) when syncing to video gear.

Unless your goal is to make short clips (3-4min each, and adjust the
offset each time), you are knee-deep in trouble without syncing your
clocks. Forget about the timecode, you make the offset adjustment only once.

OTOH you might just be lucky and have equipment that doesn't drift that
much :)


Flo
-- 
Machines can do the work, so people have time to think.
public key DA43FEF4          x-hkp://wwwkeys.eu.pgp.net


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