Posted by Pat Horridge on 10/03/05 11:23

"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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