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Setup Guides: |
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| Q: |
Does
the DAC-200 have locked audio? |
| A: |
Yes t he
DAC-200 does have locked audio. |
| Q: |
What
is the importance of locked audio? |
| A: |
Below
is an excerpt of an article written by Adam Wilt,
posted on the internet
by "Video University". |
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The
entire article may be seen at http://videouniversity.com/dvformat.htm |
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"
Since DV was designed as a consumer format, unlocked
audio was allowed as a cost-saving measure. In unlocked
audio, the audio clock is allowed some imprecision,
such that there can be a variation from the locked
spec of up to +/- 25 audio samples written to tape
for every frame, instead of a precise and exact
number. |
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This
economy measure is simply one of allowing the audio
clock to "hunt" a bit around the desired
frequency; the phase-locked loop (or other slaving
method) used to keep the audio sampling in sync
with the video sampling can have a bit more slop
in its lock-up, with the audio sampling sometimes
running a bit slower, sometimes a bit faster, but
always staying in sync over the long run. The total
amount of sync slippage allowed in unlocked audio
is +/- 1/3 frame -- not enough to really worry about. |
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It's
the difference between walking a dog on a short
leather leash, always forcing the dog to stay right
by your side (locked audio), and using a long, elastic
leash or one of those "retractable clothesline"
leashes that allows the dog to run ahead a bit or
lag behind (unlocked audio). In either case both
you and the dog will get where you're going at the
same time, but along the way the "unlocked"
dog has a bit more freedom to deviate from your
exact walking pace. |
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Unlocked audio should not cause audio sync to drift
way from video over a long period of time. The audio
clock is still linked to the video clock; it's just
allowed a bit more oscillation about the desired
frequency (more wow & flutter if you will) as
it's trying to track the video clock. Like the dog
on the springy leash, it can run a bit ahead or
a bit behind the video clock momentarily (up to
1/3 frame ahead or behind), but in the long run
it'll still be pacing the video clock and on average
will be right there in sync with it. I have shot
one-hour continuous takes of talking heads with
a consumer DV camcorder
(DCR-VX1000) and experienced no drift at all between
audio and video. |
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DV
cameras and VTRs generate unlocked audio, both in
32 kHz 12 bit and in 48 kHz 16 bit recordings. DVCAM
and DVCPRO cameras and VTRs generate locked audio
in 48/16 audio format, and DVCAM can also generated
locked 32/12 audio. 44.1kHz, discussed below, is
never locked; it has no neat integer relationship
with either 625/50 or 525/59.54 frame rates." |
| Q: |
Why
do I keep getting a Pink Screen on my monitor? |
| A: |
When
the DAC-200 is not actively processing a video signal
it displays pink. This is caused by a chip used
within the converter and cannot be changed. |
| Q: |
I
am playing video from my timeline and the converter
is losing the video for a second or two and then
comes back, what is causing this? |
| A: |
The
DAC-200 has dip switches that control the clocking
frequency when it is converting video. Dip switches
4 and 5 control the clocking frequency, if the dip
switches are not configured for your operating system
or type of device, a loss in video can occur. Please
refer to dip switch chart below and make sure that
your DAC-200 is setup correctly. |
Asia / Pacific 