[Tig] DI workflow, capabilities and requirements

Steve Shaw digital.praxis
Mon Mar 28 18:53:34 BST 2005

Hi Greg,
The iQ uses local storage to provide guaranteed disc access speeds, which
enable the system to perform 2K real-time playback without any chance of
interrupts, etc, getting in the way. This means I can playout all my video
deliverables direct from the 2K master without further processing.

Although SAN systems are getting to the stage where they can provide some
impressive speeds, there is always the possibility of a playback failure.
And they are rather expensive, especially when the required metadata
management is included, which few companies yet do correctly - BrightSystems
being the best to my mind.

Not a major problem you might thing - the odd stutter or slightly slow
playout - but clients tend to not like this as they think there is something
wrong with their film, such as duplicated frames, so get rather panicked if
this happens.

Playout to vtr will also obviously fail if the 'video stream' isn't an
accurate 24, 25 or 30fps.

One of the big worries with some of the alternate systems is that they use
unprotected Raid-0 discs to enable their speed of operation. I'm not sure my
clients would like their data to be unprotected like that. I know there will
be a backup somewhere, but a failure will still take some time to recover
from, and time is something you just never have enough of.

The iQ has a nominal 3TB storage locally, fully raid protected, and MotionFX
have about 25Tb of NAS as nearline storage.

MotionFX have a dual fibre network connecting the NAS discs to the iQ, and
push and pull data to/from them in the background, while continuing to
perform the DI work on the iQ. This data movement is totally transparent to
the operator and can be manages via a 'data monkey' from a separate PC on
the network. MotionFX get about 12fps at 2K.

I do agree with Chris that iQ needs to get its operational speed to be
real-time, which is something I know Quantel are working on. However, it's
far more important to me for any DI system to be able to perform the
necessary functions first, with speed being something that can come later.
Speed on its own, without the necessary tools and capabilities, is rather a

Hope this helps,


Steve Shaw
Digital Praxis Ltd
+44 (0)7765 400 908
steve at digitalpraxis.net

> Steve,
> When you're actually working on imagery in iQ is the data on Quatel
> hardware
> or coming directly on/off the NAS?
> Thanks,
> Greg

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