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Posted by Bill Lee on 12/21/05 05:01
In article <1133964185.303542.318110@g44g2000cwa.googlegroups.com>,
"blackburst@aol.com" <blackburst@aol.com> wrote:
> I ingested DV footage from a DSR45. When I hit escape, the computer
> told me that the audio may be out of sync.
Firstly may I suggest that you are not capturing the video in the way
that you probably should be captured. Final Cut Pro is very heavily
dependent on unbroken timecode, since it relies on that to specify the
video you want to capture and use. This makes it different to the
workflow of iMovie or even Final Cut Express where you suddenly decide
you want a piece of video in your computer and hit the Capture Now
button as the video streams out the camera or deck.
The way that I use (and teach) FCP is to run through a tape, making
entries for all the clips I want to capture with the In, Out and Log
Clip buttons. This process can often be done fairly quickly, at double
speed or faster and you don't need to be frame accurate at this stage.
When all the desired clips are logged, I then select the clips that are
worthwhile capturing, then select File>Batch Capture to digitise the
video identified earlier. If you set generous handles ("Handle Size")
for your logged clips, you can make sure that you don't miss the
beginning or end of the clips if you were slightly off in the setting of
In and Out points.
The above suggestion is extremely important in sorting out good video
from bad, especially if you have to edit someone else's camerawork and
have nothing to start with except for a box of tapes (and you may have
to even write labels on them to start with). FCP is meant to be used in
production work, where work can be passed on from person to person and
so you might not know there were 5 bad takes (or so-so takes) before the
final good one. Doing a Capture Now means you could be capturing bad
takes unnecessarily, whereas making log entries for clips allows you to
better decide what video should be captured and what is best left on
tape, and also how you can later change your mind and get one of those
'other' takes quickly captured if the 'good' take is not as good as it
first appeared.
Where am I going with this, when all you wanted to know why FCP is
reporting your captured clip out of sync? Well, the process of Capture
Now is not the best way of using FCP, and comes with some limitations.
Older versions of FCP (pre-4.5 from vague recollection) reserved and
prepared disk space able to store the value set in the Preferences of
"Limit Capture to xx minutes". This took time, and while FCP was
clearing space for the video, frames were being lost. Newer versions of
FCP don't pre-reserve disk space for the video and so have less of an
issue. The use of Capture Now can cause loss of frames in the capture
process and this may be responsible for out-of-sync video.
Once video is captured you can use the Tools>Analyze Movie>Clip to see
if there are any clips that are shorter or longer than they should. Are
the durations of the video and audio the same?
If there seem to be problems then try recapturing the video clip by
selecting the clip in the Browser and selecting File>Batch Capture to
recapture the video under automated control. The computer will cue up
the deck and recapture your clip. Then run the Tools>Analyze Movie>Clip
to see if the problems have disappeared or at least improved. Also check
with the video and ensure that things are out of sync, since it might be
just a warning and actually unnoticable in practice..
> How do I insure that the audio is locked?
This is not something you need to worry about. See:
<http://www.adamwilt.com/DV-FAQ-tech.html#LockedAudio>
I guess this might be the cause of your error message, where the number
of audio samples captured does not match up with the actual frames
captured, and so it gets reported as a possible sync issue. If that is
the case you can safely ignore the error message. Audio that is 1/3 of a
frame out of sync with the video will not be noticeable, unless you need
to sync the audio up with another audio soundtrack, and then you can
sync the audio up within the frames to within 1/100 of a frame.
> Which option do I select in Log & Capture? DV NTSC or
> DV NTSC Basic?
The difference between the two is to do with the control commands that
are supported by your tape deck and passed over the FireWire cable. This
will have no effect on the video/audio data that is transmitted from
tape to the computer. Unless you are having problems with your deck
automatically cuing up tapes and being under your keyboard control you
should choose DV NTSC.
Bill Lee
P.S. Avoid broken timecode. If you have broken time code and you are
working on a project that your are sure will only require you to capture
your video once, you may get by with broken time code (but I still
wouldn't recommend that you do this). Since FCP relies so heavily on
good unbroken timecode for repeatability and workflow, then you really,
really, really don't breaks in timecode on your tapes. If you have them,
caused by bad shooting technique, then think about doing a camera-deck
digital transfer to ensure an single unbroken timecode tape. After
working for a couple of days trying to manually cue up a box of tapes
each with numerous broken timecodes caused by poor camerawork, you will
feel like taking a baseball bat to the person who allowed this to happen.
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