|Sidebar 6 to 'Apple QuickTime 3.0 and the Avid/Microsoft Advanced Authoring Format ' Article
Much more than a SMPTE SFX Registry is needed to succeed
The major difficulty with transferring complete digital video project metadata (a so-called 'rich EDL') is the specification of effects, transitions, and composited moving layers. The AAF promoters say they will use a 128-bit AUID (authoring unique identifier) like the Internet GUID (globally unique identifier) to give each effect or transition a unique number. This would extend the current 150 or so SMPTE wipe numbers, and would be implemented by a SMPTE committee called the SMPTE Registration Authority (SRA). Much more than special effects can be registered.
The idea sounds great in the future Internet where COM objects will be for sale, accessed by D-COM or CORBA technology over the web. If you import an effect that you don't have, simply click on the AUID number at the SRA web site and you can download the effect plug-in binary code for your editing software and your platform. But it is out of touch with the way transitions and effects are being built today.
The current SMPTE wipes are fine in an online switcher environment, where you set the wipe pattern and duration and press Auto Take. But a single number is a hopeless failure in a sophisticated nonlinear editor, where most transitions and effects are programmable and keyframable.
There are currently over 20,000 effects available as plug-ins, most with many keyframable parameters. If the original editor sets any of these parameters, effects will not be the same unless the metadata sends all the keyframes and all the parameters, and the importing system knows how to map all the parameters and keyframes into its architecture. Quantel has introduced effects that can be programmed by end users in Java. The granddaddy of all effects packages, Adobe After Effects, can generate tens of thousands of bytes for an effect description. And while Adobe has published specs on how to write plug-ins, they have not published how their host software handles everything, forcing developers to reverse engineer After Effects (and Photoshop and Premiere). Are they likely to give this all up soon? To be sure, Avid's new AVX specification is a step in the direction of open effects descriptions. And leading effects companies like Artel and Digieffects have a strong interest in making their cross-platform packages capable of exchanging effects metadata.
The bottom line is that exchanging effects between say a Media 100 or Scitex and an Avid is a wonderful idea, but not likely from companies that today cannot exchange M-JPEG files created on the same LSI codec chip set.