Linux and Scooby-Doo

Scooby-Doo, the computer-generated dog in
the Warner Brothers film of the same name, was created using Linux.
Scooby-Doo was released on June 14, 2002 and
stars Sarah Michelle Gellar, from the popular TV show,
Buffy the Vampire Slayer. Live footage for the
film was shot in Australia, and the Scooby-Doo character was added
electronically later.

Animators at the Los Angeles post-production studio
Rhythm & Hues used
Maya,
Houdini,
Film GIMP and proprietary
Linux-based tools. "We utilized about a hundred Linux desktops to
create Scooby-Doo", says Technology VP Mark
Brown. "My biggest problem was all the animators yelling at me for
more Linux boxes."Film GIMPFilm GIMP is the motion picture version of the popular
open-source GIMP image editing program.
Scooby-Doo was in production at the time I
visited the studio for my article, "Film GIMP at Rhythm &
Hues", which appeared in the March issue of Linux
Journal. Both a developer and a user of Film GIMP,
Rhythm & Hues keeps a few Windows and Mac OS X machines around,
mainly for compatibility with Adobe
Photoshop.After the article appeared, some readers asked why Photoshop
is being used rather than the GIMP. Film GIMP developer Caroline
Dahllöf, a programmer at Rhythm & Hues, "Photoshop handles
more layers with big images better". Matte painting artists at
Rhythm & Hues create large backgrounds with perhaps forty
layers and use a lot of specialized plugins. Working on single
large images is quite different from the typical Film GIMP tasks of
retouching film frames to remove dust or wire rigs. To get rid of
Photoshop completely would require investing a lot of developer
resources."I really wish that there would be an official effort and
that I had more time to contribute", says Dahllöf. "Right now
we're really busy, but I hope to have more time for Film GIMP this
summer".I myself am joining the project. The first things I want to
accomplish are updating the Film GIMP web site and providing a
source tarball so it isn't necessary to check out Film GIMP from
CVS.

Film GIMP development perhaps has a renewed urgency because
Apple recently acquired
not only Nothing Real's
Shake (see my May article in Linux
Journal, "Tippett Studio and Nothing Real's Shake") but
also Silicon Grail's
RAYZ. Film GIMP, Shake and RAYZ are the three available
Linux compositors; all the other Linux-based compositors are
proprietary, internal to the studios that developed them.Steve Jobs reportedly visited motion picture studios months
back and took copious notes about to how best position Apple in the
motion picture business. Buying Shake brings Apple the leading
commercial film compositor, and in buying RAYZ, it has acquired the
most significant Linux challenger. Apple stated that they intend to
continue Linux support for at least one more version of Shake, but
users worry that Apple seems lukewarm in their support for Linux.
More Linux compositors, however, are on the horizon.At the National Association
of Broadcasters (NAB) convention in April,
Discreet
showed their Combustion product ported to Linux, though not yet
released. Digital Domain says it may release NUKE, its proprietary
compositor that has won two Scientific and Technical Achievement
Academy Awards. ILM also has a highly regarded Linux compositor
called CompTime (described in my July
2002 Linux Journal article,
"Industrial Light & Magic"), but there are no plans to release
it. A source at Adobe says there also are no plans to port
After
Effects to Linux, but they did release Adobe Acrobat for
Linux in May without fanfare.The Computers of Rhythm & HuesRhythm & Hues has 125 Linux desktops and 300 SGI
machines. Brown expects to complete the phasing out of SGI desktops
by the middle of 2003. "Those doing the heaviest work are using
Linux for performance", says Brown. "Productivity using Linux is
through the ceiling. Interactively, Linux is five to six times
faster than the SGI workstations being replaced"."Our desktops are all dual-processor rackmounts, split 50-50
between P3s and Athlon MP 1800+", said Brown. Animator desktop
machines are remote rackmounts kept in the machine room, connected
with Cybex KVM extenders. Brown says that 3U racks were chosen to
avoid any weird AGP risers. The graphics cards are ATI FireGL 2.
"We're looking at FireGL 8800 Radeon cards", notes Brown, "but the
drivers are not ready yet." They like the FireGL 2 cards because of
the overlay planes (which work well with their software) and
because they are good at manipulating heavy, complex 3-D
geometries. Their machines use single monitors, not dual
head.The renderfarm, where the individual motion picture frames
are computed, has 150 dual Pentium 1Ghz and 60 dual Athlon MP 1800+
machines. "AMD chips scream for our applications", says Brown. "I
can't tell you how impressed I am. An Athlon MP 1800+ gives about
the same performance as a 2.2G Pentium Xeon but at a third of the
price, if that." The render PCs all have separate IP addresses.
Rhythm & Hues uses its own custom queue for batch control,
which also uses the desktop machines as render nodes during their
idle cycles."We've ported our software and have all that running on
Linux", reports Brown. "We're using
Red Hat 7.2 and
XFree86 4.1. We use the
ATI OpenGL libraries, the SGI GLU libraries and the Mesa 3.4.2
GLUT."
Mesa
recommends the SGI GLU library version 1.3 over its own 1.2
implementation because SGI's is more up-to-date and reliable. Brown
created
scripts
to switch between various library permutations for testing and
benchmarking."Linux is stabilizing for us", says Brown. "For instance,
normal operations are fine, but the Thunder K7 Tyan AGP 4x
motherboard will wedge in our fire-hose tests". Brown says they
probably will switch to ASUS or Gigabyte motherboards. Blue Arc,
Network Appliance and a custom Sun box are the backend NFS servers.
"You just can't serve terabytes of data off a Linux box now",
states Brown. "Throughput is about a third of what it should
be".Rhythm & Hues chose
Angstrom
for their rackmount PCs. "Angstrom does a good engineering job and
has a good team", says Brown. "They did well with the burn-ins, and
their prices are good. We get monster machines for $2,500. If I had
the money, I'd throw out every SGI now and get Athlons".Angstrom MicrosystemsLocated in Boston, Angstrom Microsystems creates ultra-dense,
high performance rackmount servers. "Our cooling and our quality
are what make us unique", says president Lalit Jain. "We're moving
heavily into the render market. Customers include Pixar and Rhythm
& Hues". Angstom sold several thousand servers to Akamai last
year for streaming web pages and internet video."The Quad2000 just released is the highest compute-density,
four-processor rackmount available", says chief architect Ravi
Soundararajan. "That uses the Athlon 2000+ rated for 2100. Angstrom
does a lot of customized cooling, which is how we get to this
density". Despite the density, the 4-CPU 1U system is air
cooled.Asked if Angstrom was considering low power chips for its
servers, like the architecture of the Transmeta
Green
Destiny supercomputer, Jain says no. "Not the Transmeta
Crusoe, but we scrapped a dual Mobile P3 design we were working on.
It would have been four to ten times the price of a comparable P4
system and didn't save any power due to the added
components."Green Destiny is a 240-blade Beowolf cluster that operates
air cooled in an 80-degree warehouse at Los Alamos National
Laboratory. (Linus Torvalds was among the luminaries at the
unveiling in May 2002.) Soundararajan points out, "Angstrom servers
can run reliably in 100-degree rooms." He also says that Angstrom
servers are working perfectly in foreign countries where there is
no A/C. Less air-conditioning also conserves machine room power, a
difference felt not so much in power bills (electricity) but in
avoiding the costs of building wiring and A/C upgrades
(electricians).Soundararajan says Angstrom has been working closely with AMD
and ATI on a graphics bug related to AGP. "There's corruption of
video and lockups. We've tested in-house on a number of different
AMD boards with the 760 MPX chipset and all have the same problem."
The Linux community has been discussing, on the Linux-smp list, a
related bug that causes AGP data to be lost during SMP operations.
(See the sidebar for more details.) Angstrom sent a machine with a
reproducible bug configuration to AMD for testing. Angstrom testing
is continuing with NVIDIA cards and Pentium motherboards;
Soundararajan found that some of those machines are crashing
similarly. Finding solutions to these sorts of problems is part of
Angstrom's appeal over generic hardware.The AMD AGP Linux Kernel
Patch"I think everything 32-bit will be replaced by 64-bit in a
year and a half" says Jain, "and AMD will be phasing out 32-bit
servers and desktops". AMD's 64-bit CPU is backwards compatible to
run 32-bit applications, but temperatures tend to rise with
performance. "If AMD continues increasing cooling requirements,
we'll have to go to liquid cooling. We're looking at whole rack
cooling with water." Angstrom is focusing on 64-bit systems and on
software to manage clusters and network operations centers.ConclusionFilm GIMP is the only open-source compositor used in feature
motion picture work. Scooby-Doo is the latest
motion picture to utilize Film GIMP, a list for Rhythm & Hues
that includes Harry Potter, Cats
& Dogs, Dr. Dolittle 2,
Little Nicky, The Grinch,
Sixth Day, Stuart Little
and Planet of the Apes. While there may be
some growing pains, the motion picture industry is finding Linux
very much to its liking. Compatibility with proprietary UNIX-based
studio applications, performance, cost and the Linux community's
highly regarded responsiveness in correcting issues are all factors
in this movement.Robin Rowe is a partner in
the motion picture technology company
MovieEditor.com. He
leads two users groups,
LinuxMovies.org and
OpenSourceProgrammers.org.

email: robin.rowe@movieeditor.com