Arri Syncbox
Noah Timan
involves use of a large video screen. 24 FPS playback is not possible for this
video projection (it's live video), so to eliminate rollbar problems the camera
department is going to use a sync-box with the Arriflex camera. The video sync
signal (29.97 FPS, regular NTSC video) from the video source will be used to
feed the sync-box, which will in turn feed the film camera's crystal. The
project is for television and will die on video, so there are no
projected-at-24-FPS issues to worry about, but I am a little concerned about
the device as it "phases" in the video sync. It sounded from the DP's
description that the camera makes several speed "adjustments" before it locks
in the sync signal from video, and I'm concerned that this "adjustment" period
will cause telecine problems while it matches up my 29.97 FPS TC with the
Arriflex 29.97 FPS TC. It's a documentary, so the option of slating once sync
"locks" from the syncbox (assuming that there is some visual confirmation of
this that the DP can recognize) may not be available.
How about variations between the video-source's 29.97 and the audio recorder's
(in this case, a Fostex PD4)? I assume that the difference between "true"
29.97 and what the sync box will deliver would be negligible at best, but I'm
wondering if others have experienced anything different....
Does anyone have any experience with this process? Any advice on this concern
would be greatly appreciated!
Thanks for your help and time.
Regards,
Noah Timan
Frank Kruse
you use a capperboard just mark the slate AFTER the rollbars have been
phased out and make a not in youn sound report that these takes are
29.97fps. if your film is 24fps and transferred to the avid everything will
be out of sync because 100% is 24fps. so you have to either pitch or
timestretch your sound. all this can´t be done in telecine. you could use a
nagra 4.2 with neopilot but the modern arris (SR3, 535, 535B etc.) don´t
output a pilot tone :( the difference between 24 and 29.92 is allmost 5
frames p. s. so this is A LOT.
there is no sollution for this problem besides loosing either pitch or tempo
of sound.
frank.
--
Frank Kruse
Sound for Motion Picture
fr...@wildtrax.de
www.wildtrax.de
on 13.12.2001 19:15 Uhr in 20011213131520...@mb-cm.aol.com Noah
Timan noah...@aol.com wrote :
--
Frank Kruse
Sound for Motion Picture
fr...@wildtrax.de
www.wildtrax.de
William Sarokin
alignment between the camera shutter and the projected image. If they need
to run at a speed other than 29.97, just make sure the telecine people know
the exact speed so they can dial it in on their machines.
Billy Sarokin
Peter Schneider
When I 've seen it work, it usually happens like this:
Sound Rolls
Video rolls
Camera turns on, cameral asst. phases to video image
the scene is slated
One thing I try to do is to change tapes if I change TC rates, so that one
DAT tape has 30fps tc, the other 24fps tc - this way there is (hopefully)
less confusion in telecine.
If you are concerned about drift, you can also tail slate.
Regards,
Peter
"William Sarokin" <big...@bellatlantic.net> wrote in message
news:ajcS7.1503$BK....@nwrddc02.gnilink.net...
Peter Schneider
*29.97* time code.
-Regards,
Peter
"Peter Schneider" <Pschn...@nyc.rr.com> wrote in message
news:O7hS7.206602$XA5.34...@typhoon.nyc.rr.com...
Noah Timan
take care of this issue as we could point telecine toward a TC value set after
phase and sync are locked. However, we're filming a stage performance and
there is concern that the slate will be too distracting for other audience
members.
Instead, we will use Arri TC -- my only concern with this system is that
telecine may pick a TC value before phase and sync are locked, thereby creating
an offset. If what Billy is saying is true, though, and the phasing process
from the syncbox does not affect speed, it shouldn't be an issue.
Otherwise, perhaps I can see if a silent slate -- i.e. just TC numbers and no
clap -- would be acceptable, although I'm going to be set up far away from the
camera department, so it will be difficult to enforce this procedure.
Thanks!
Noah
<< Hi Noah,
<snip>
robert sylvain
hopes of saving someone similar embarrassment. The first time I rented a
PD-4, I recorded a little in my hotel room the night before just to be sure.
Then I laid down my tone to get a head start. Smart, right? Well, the next
day, the director asked me to set it to drop frame, so I changed it. I
noticed that the frame rate display blinked, but being new to the unit, I
ignored it. Come to find out that the PD-4 has a "feature" so that once a
frame rate is begun on a tape, it continues at that frame rate no matter
what the knob is set at. Some veterans may scoff at my ignorance, but I was
surprised as hell to find out the time code was all wrong, and if it helps
one poor soundo, it's worth it.
Robert,
Portland, Maine
in article 20011214115820...@mb-ct.aol.com, Noah Timan at
noah...@aol.com wrote on 12/14/01 11:58 AM:
robert sylvain
rob...@gigafone.com wrote on 12/15/01 2:25 AM:
> Come to find out that the PD-4 has a "feature" so that once a
> frame rate is begun on a tape, it continues at that frame rate no matter
> what the knob is set at. Some veterans may scoff at my ignorance,
Or they may scoff at my bad grammar...
Frank Kruse
possible to change the rate.
frank.
on 15.12.2001 8:25 Uhr in B84065C5.2172%rob...@gigafone.com robert sylvain
rob...@gigafone.com wrote :
--
Chris Price
all players and recorders as is common proctice in post prodution. The
camera, the video wall player and the sound should be fed with video syncs
or wordclock as appropriate. The arri camera can phase out the bar as with
the phase button and then all machines run sync any way.
Using a betaaplayer or any other with gen lock input will keep the video
wall in sync and the arri camera can phase and lock to the stable source
There is a very good 19" rack sync box called Nanosyncs which give a stable
video and wordclock locked to the video,other wise two synced Lockit boxes
, No cables!! would pevent the bar from reappearing,and keep all units in
sync,
Hope this helps
all the best
chris price
Wolf
FILMING VIDEO MONITORS
FILM SHOOT 24 FR – 144º SHUTTER – 59.97 FR VIDEO
If the film camera is running at 23.97 frames and the shutter is set at exactly
144º and video plays at 59.97 then all is well and normal sound should run at
29.97 for DAT. Video on the monitors will look good if color corrected and
exposed properly. Only super technophiles will see on the projected 35mm print a
small area in the mid video screen where there seems to be a few video lines
that are slightly lighter than others. Panavision, Arri and Movicam cameras can
be adjusted to 144° nowadays.
It matters where the axis of rotation of the shutter is. If it's alongside the
gate, as in Mitchells, Panavisions, and Arri 2C's, the shutter edge is roughly
horizontal, and travels vertically. This produces a horizontal roll bar, because
the shutter edge is roughly parallel to the TV scan lines. The whole point of
these numbers is to get an exposure time equal to the TV field rate, so that the
size of the roll bar becomes zero lines. If the shutter axis is below the gate,
as in Aatons, Eclairs, and a lot of the other Arris, then the edge passage is
very roughly perpendicular to the TV scan lines, and the roll bar gets a
diagonal or curved fan shape. Because the horizontal scan is much faster than
the vertical scan, these artifacts are much larger and dimmer than the
horizontal roll bar. If you're looking through the gate at this phenomenon, you
can see what the other way looks like just by turning the TV set - or the camera
on its side. All this is adequate as long as the TV is an unimportant BG object.
If you need to do an insert of the TV screen, even the "zero line" roll bar will
appear as a discontinuity in moving objects. Effectively, you're getting a matte
shot between two copies of the same video, but with the top one frame out of
sync with the bottom (in the horizontal case).
Yes, this also changes the 'look' of motion very subtly. To keep the fuzzy bar
in the same place a Cinematography Electronics (Barton) Box is needed to phase
film camera to video playback.
Curious that this simple solution is so often forgotten, could it be that the 24
frame rental companies have virtually no rental in this situation? Or are we so
addicted to hi-tech that we do not even consider the simple answers anymore?
With 144° shutter and 59.97Fr video looking through the camera viewfinder the
"24 frame operator" (often the camera assistant) should adjust (by pushing the
phase button) the fine grayish line into center of frame using the
Cinematography Electronics (Barton) Box (also called sync box or phase box). He
can be looking at the mirror in the gate or viewfinder. Once done this does not
change for the rest of the setup. The line is not visible on film because of a
slight overlap of 2 video lines. Cinematography Electronics (Barton) Box locks
59.97 video to film shutter and camera actually rolls at 23.976. Now sound has
to run at 59.94Hz for pilot tone or 29.97 for DAT reference.
There is a question if the nearly invisible overlap of two video frames last and
first lines will wander with 24 exact frames per second camera speed and 59.97
video speed.
The ARRI 535 viewfinder seems to show 5 lines that can be phased at first. A
trained eye can find the correct thin gray one. Allen Landecker (VTE Simi
Valley) has a device to replace the sync cable with a wireless setup.
If you have several tape sources for monitors you don't want to use the 144°
shutter method; use 24Fr video (vs. 59.97). None of the video decks would be "in
sync", meaning the sync bar will be at different places on different monitors.
There are of course decks (usually 3/4") than can be synced up with an external
reference sync delivered by a signal generator.
Don't forget the average TV monitor has a very blue (daylight like) image, they
are balanced for daylight. It takes a trained eye to get the colors right for
tungsten film with incandescent lights.
John Sprung <John_...@paramount.com> further says:
For NTSC television, which operates at 59.94 Hz:
Film camera at 24 fps, shutter angle 144.14 degrees (little unusual)
Film camera at 25 fps, shutter angle 150.15 degrees
For PAL/SECAM television, which operate at 50.00 Hz:
Film camera at 24 fps, shutter angle 172.8 degrees
Film camera at 25 fps, shutter angle 180.0 degrees
Shoot a test - slate it well - develop it - project it. Make up your mind. Don't
trust anybody!
FILM SHOOT 24 FR – 180° SHUTTER – 24 FR VIDEO
It is true that 24 frame video playback with 180° shutter (rather than
29.97-144°) does really look better on a large projected image in the theater.
Two major speeds are in use: 24 or 24.021777 frames per second. They are
different and have to be handled differently, of course
How it works: Special video monitors run at the special refresh rates being fed
by special video decks running at special 24 like speeds, controlling film
cameras with 180° shutter at 24 or 24.02 Fr/Sec with special “speed boxes”.
Sound gets a 60 or 60.05 Hz sine wave (for external Nagra Pilotone) input from
special video playback equipment’s sync generators. If 24.02 is used the 60Hz
external Pilotone is proportionally sped up to 60.05, after resolving all is in
sync again and all is well. This works equally for the mono Nagra 4.2 and stereo
Nagra FM, but not really with DAT.
Today (1998 and still in 2001) most 24 frame companies use the exact 24Fr speed,
not 24.02: Steve Irvin (Playback Technologies), Bob Morgenroth (E=MC2), Allen
Landecker (VTE), Dick Clark (InterVideo). But Warner Bros. and Hill can be 24.02
or 24. They send 60.05 Pilotone to the mixer for his Nagra. Good 24 frame
companies use sync generators that can provide either 24.000 and 24.02. If the
24 frame video playback operator on the set does not know the exact speed of his
system, call his head office and get good info. Always write down the name of
the person giving you information over the telephone.
Greg McMurry, Video Image Associates, gives us this list of running times and
corresponding sync error if the Neopilotone Nagra (or Neil Stone TC conversion
of non-TC Nagras) is not fed the modified sync signal of 60.05 based on real
24.02 camera speed but rather records at 60 Hz Pilotone (the wrong speed).
Error Rate Differential 24-24.02
Minutes 1 2 3 4 5 6
Frame error 1.31 2.61 3.92 5.23 6.53 7.84
It is a good precaution to isolate the Pilotone input to Nagra with a good
quality transformer which gives you additional control over ground and a margin
of safety from weird loops and noises. Video systems often being huge and
complex and sometimes uncontrolled often make compromises in grounding
techniques. It is always a "sound problem" when the video guys can’t provide a
clean 60Hz. (“Nothing like good old iron,” Wolf’s been saying for years, and we
have been using Jensen’s [none others] with predictable results.) Be prepared.
This method has been practiced since the 1970s and is well established and
works. So far so good with the old media.
Most "sound problems" are caused by others, but the sound department can provide
a solution. Therefore, by Hollyweird logic, they are "sound problems", not
"sound solutions."
Is there any justice in this world?