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Movies Forum Index » Movie Production (Sound) Forum » Some Audio Questions
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| Tony Muricy |
 Posted: Thu May 13, 2004 7:44 pm |
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Hi Guys!
There has been some discussion in our Sound Association here between
Sound Mixers and Sound Editors about
a) the procedure of , when shooting with a digital video camera, have
a TC DAT recorder running parallel with an analog sound line feed to
the digital audio tracks in the camera, and the producers considering
the DAT as a backup of this sound captured in the camera digital audio
tracks. How good is this camera audio, considering diferent formats,
like Digibeta, HDTV and DvCam and MiniDv? Can it be used with no
problems, or should it be replaced by the original DAT sound when
comes the sound editing? Is there tests made to determine the sound
quality of these cameras ?
b)The same concern about audio captured and sincronized in the Indaw
at the telecine station - is it good enough to be edited and
considered as a final sound track? Or should it always be replaced?
c) The fact that very too often the sound sincronized in the telecine
through the Indaw is actually out of sinc - from two to much more
frames. And many times (20% to 30% in my experience)it doesn't
sincronize at all! Is this normal or it's an operator's or machine's
fault?
Thank You very much!
Tony Muricy |
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| Jay Rose CAS |
| Posted: Fri May 14, 2004 11:06 am |
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Quote: Hi....How good is this camera audio, considering diferent formats,
like Digibeta, HDTV and DvCam and MiniDv? Can it be used with no
problems, or should it be replaced by the original DAT sound when
comes the sound editing? Is there tests made to determine the sound
quality of these cameras ?
A couple of years ago, I set up a bunch of miniDV cameras (and some other
recorders for comparison) with test equipment, measuring mic- and
line-level ins to digitized out, testing for s/n, THD+N, response, and
anomolies like aliasing. Partial results are in the archive at DV.com.
I've continued the tests with newer units, and there's much more on the
subject in the second edition of Producing Great Sound (dplay.com). In
general, miniDV is not up to 30-year-old analog standards... but there are
ways to improve it, or at least get the best out of it.
But you also have to consider transfer method. FireWire from camera to
NLE, and then OMF or similar to DAW, is essentially lossless. Analog out
of a DAT to NLE or DAW can be much worse depending on the equipment.
Quote: b)The same concern about audio captured and sincronized in the Indaw
at the telecine station - is it good enough to be edited and
considered as a final sound track? Or should it always be replaced?
Indaw - which is one mfr's product and not necessarily available at all
telecines - should be a clone of the production DAT iirc. But lots can go
wrong in the NLE stage, including sloppy transfers, so unless you're sure
it can be a good idea to replace with simulDat. I'm not sure how Indaw
handles 24-bit audio. Anyone?
--
Correct address is spell out the letter j, AT dplaydahtcom
Clio- and Emmy-winning sound design
Learn audio for video at www.dplay.com |
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| Marty |
| Posted: Fri May 14, 2004 11:13 am |
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I'm sure there will be other responses from people more familiar than I
with the post process, but here are some things I can contribute:
Tony Muricy wrote:
Quote: Hi Guys!
There has been some discussion in our Sound Association here between
Sound Mixers and Sound Editors about
a) the procedure of , when shooting with a digital video camera, have
a TC DAT recorder running parallel with an analog sound line feed to
the digital audio tracks in the camera, and the producers considering
the DAT as a backup of this sound captured in the camera digital audio
tracks. How good is this camera audio, considering diferent formats,
like Digibeta, HDTV and DvCam and MiniDv? Can it be used with no
problems, or should it be replaced by the original DAT sound when
comes the sound editing? Is there tests made to determine the sound
quality of these cameras ?
While cameras are advertising 24 bit audio which pertains ony to the A/D
convertor, the digital bitstream on tape can be only 16 bits on some
cameras. The DAT tracks will be much higher quality. The difference may
not become obvious until the tracks have been transcoded a few times,
whcih of course, will be too late to fix.
Quote:
b)The same concern about audio captured and sincronized in the Indaw
at the telecine station - is it good enough to be edited and
considered as a final sound track? Or should it always be replaced?
c) The fact that very too often the sound sincronized in the telecine
through the Indaw is actually out of sinc - from two to much more
frames. And many times (20% to 30% in my experience)it doesn't
sincronize at all! Is this normal or it's an operator's or machine's
fault?
The digital video process incurs latency delays, which will offset it
separately from the audio.
Marty Atias
ATS Communications
Quote:
Thank You very much!
Tony Muricy |
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| Balazs Rozgonyi |
| Posted: Sun May 16, 2004 3:48 am |
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I have no experience with DigiBetas and we using Sony HDcams as only
source of audio for a daily series shooting, but be very careful with
DVCAMs. most cameras offer 16bits of max resolution in 2 channels, and
when switched to 4 channels it goes down to 12 bit which is very low
(remember, 12 bit means max. 70dB S/N!)
Balazs Rozgonyi
R-Provideo Hungary
web.axelero.hu/rprobt |
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| Oleg Kaizerman |
| Posted: Sun May 16, 2004 4:10 am |
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only if you run dv , you are recording 4 track 12/32 and this only on one
existing camera xl-1 , all the others recording 2 channels and have
capability
to do insert additional tracks after (dub)
the , Sony hd ,digi beta , imix , Pana 900 dvcpro and others have ability
run 4 track 16 bit
part of them as regular inputs +( front mike and receiver slot in ) and
part as additional board or adaptor which connecting to the camera .
in some cameras the bit rate goes down from 20 to 16 bit while recording 4
tracks at ones ( hd,digi beta)
Sny dvcam format can handle 2 channels only with 12 or 16 bit not 4
--
Oleg Kaizerman (gebe) Hollyland
"Balazs Rozgonyi" <rprovideo@axelero.hu> wrote in message
news:6aaf7597.0405160148.22e38ee1@posting.google.com...
Quote: I have no experience with DigiBetas and we using Sony HDcams as only
source of audio for a daily series shooting, but be very careful with
DVCAMs. most cameras offer 16bits of max resolution in 2 channels, and
when switched to 4 channels it goes down to 12 bit which is very low
(remember, 12 bit means max. 70dB S/N!)
Balazs Rozgonyi
R-Provideo Hungary
web.axelero.hu/rprobt |
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| avid@xs4all.nl |
| Posted: Mon May 17, 2004 1:29 am |
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14-05-2004 03:44 "Tony Muricy" :
Quote: c) The fact that very too often the sound sincronized in the telecine
through the Indaw is actually out of sinc - from two to much more
frames. And many times (20% to 30% in my experience)it doesn't
sincronize at all! Is this normal or it's an operator's or machine's
fault?
Both.
In my experience, syncing picture and sound based on timecode, both in
telecine and in NLE, is kind of in sync, ergo, not quite in sync. I always
manually correct sync, between -10 and +10 perfs (quarter frames), sometimes
up to 25.
Strange thing is, that I get these numbers when working with TC-DAT. On my
latest project, recorded by Roberto on Cantar, these numbers vary between -5
and +5.
Haven't been able to thoroughly test why that is, I just take it for
granted.
I like TC for fast syncing, but IMO you always have to manually correct.
--
Job ter Burg, NL |
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