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Posted by blackburst@aol.com on 10/03/05 13:46
Again and again I hear anecdotal accounts that you've never experienced
out of sync audio from DV, with the implication that it doesn't happen.
I HAVE had several instances of this when dubbing from DV to DVD. So
maybe the problems are with DVD recorders and unlocked audio. You can't
deny that it happens occasionally because it HAS happened to me. And
I've worked in TV for a quarter century.
Pat Horridge wrote:
> "Richard Crowley" <rcrowley@xpr7t.net> wrote in message
> news:11jvpat22ckffff@corp.supernews.com...
> > blackburst wrote ...
> >>>From Sony DSR-45 manual (a deck which plays/records both DV
> >> & DVCAM), page 101:
> >>
> >> "There are two modes for audio recording: Lock mode and Unlock mode.
> >> In Lock mode, the sampling frequencies of audio and video are
> >> synchronized. In Unlock mode, which the consumer DV format adopts, the
> >> two sampling frequencies are independent. The lock mode maintains high
> >> compatibility with the higher formats (DVCAM) and is more effective
> >> than the unlock mode in digital processing and smooth transition during
> >> audio editing."
> >>
> >> The accompanying chart lists DVCAM as Lock mode and DV as Unlock mode.
> >
> > No dispute about what "locked" vs. "unlocked" means.
> >
> > The confusion seems to be that we're assuming that "unlocked"
> > implies "audio drift" which it does not. Anyone can prove this
> > by simply playing back any DV tape.
> >
> > Note that your quote only speaks of "smooth transiton during
> > audio editing" as a benefit of "locked". No mention of drift.
> > In practice I have never encountered "unsmooth transitions"
> > during editing DV shots, and I've never heard of anyone here
> > who experienced such a thing either.
> Quite.
> I seem to remeber that even in unlocked mode the audio sync is constrained
> to a window of drift and that's measured in samples which is fractions of a
> frame.
> We use DVCam and DV here a lot and never had a problem with sync that wasn't
> tracked to a problem elsewhere in post.
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