Recording direct-to-disk with the Canon XL H1
virtually everything on board. Somehow this also includes shooting
multiple cameras, tapeless, uncompressed acquisition from a video
camera not designed for such a workflow, and editing right on deck.
audio post facility specializing in creating 5.1 surround sound remixes
for DVD releases, wanted to produce a 12-part series on the tall ships
and the people that sail them, he began investigating cameras for the
shoot.
“We did some tests with DP Scott Billups and settled on the Canon XL H1
for a number of reasons,” says Margouleff. “It’s a tremendous value for
the money. The one big thing is the quality of the glass. Canon has
been making lenses for so long that that is really what is amazing
about this camera.”
To preserve the optimum quality coming out of the camera and to be able
to edit immediately on the ship, Margouleff wanted to record
direct-to-disk and bypass the MPEG compression. By shooting
directly HD SDI out of the camera to a Wafian HR1 disk recorder,
Margouleff thought he would be able to shoot in 24p and edit
immediately on-set.
Margouleff, however, quickly found that this was not so simple with the
XL H1 and turned to Cineform for help.
“If you are transmitting 24p material you typically add pulldown to
make it a 60i signal so it is compatible with interlaced monitors,”
explains David Taylor, CEO of Cineform. “That’s what Canon is doing out
of the XL H1. The have 24p and add pulldown to make it 60i. [To edit in
24p] what you want to do is reverse the pulldown. Normally what you do
when you add pulldown is you turn on a flag in the SDI stream that
notes the added fields and equipment on the other end recognizes the
redundant field and throws it away. Canon didn’t do that. They did not
set the pulldown flag. So when we receive 1080i on the other end there
is no idea that there has been a pulldown. But we know that the Canon
is putting out 24p and it added pulldown so we developed an image
processing routine that looks at all the fields coming in and through
that it recognizes the redundant fields and throws them out. I have a
feeling that when Canon just didn’t think it would be used in this
manner. So what we’ve demonstrated is that what was envisioned as a
monitoring port is actually a high quality ingest
port.”
Another obstacle in the tapeless workflow via the HD SDI line in the
Canon XL H1 is that there is no embedded audio or timecode.
To capture the timecode they run a line out of the LTC jack into the
Wafian box. Currently the audio is running from the unbalanced outputs
of the Canon XL H1 to the Wafian box, but this again posed synch
problems.
“Audio data comes down the cable to the Wafian box a lot faster than
video,” says Jeff Youle, CEO of Wafian. “So we developed a setting on
the HR1 that delays the audio enough so that it will be in synch.”
For recording more than two audio channels, which the
audiophile/producer certainly wants, they will have to shoot double
system.
“Canon set the camera up basically for high-end ENG use,” comments
Margouleff. “But where the camera is going to find a home is in low-end
feature production. The audio works fine for 60 and 30, but if your
shooting 24p out of the HD SDI you must shoot double
system.”
In addition to using the Wafian HR1 as an HD deck, Margouleff also
loaded Adobe Premiere and Cineform Prospect HD on the box so they could
edit right on the deck of the ship.
“Being able to see a rough cut while we re still on the ship let’s us
know if we need to get an extra shot to fill any holes,” says
Margouleff. “Plus we can then apply the money that we would have used
for the offline towards better shooting, better lighting, more
equipment and talent. [Shooting direct-to-disk] makes the medium
incredibly flexible and powerful.”
But Margouleff isn’t stopping to push the technical boundaries here and
plans on a multi-cam shoot on the ship with many of the cameras
controlled remotely from the PC and using an HD SDI switcher to shoot
and cut the show live.
“I know it’s a combination of television and cinema but that’s where we
are heading,” says Margouleff. “The camera also offers a console
whereby we can have all the controls of the camera ‘ the chroma,
metering, etc. – on a laptop connected by FireWire so I can put a
camera up on a jib or rig it up on the mast. I can set up one camera
and then transfer that setup to other cameras so I can have all the
cameras matched.”
Crafts: Shooting
Sections: Creativity Technology
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