Please post documentation and/or sample code with the specs and requirements necessary to produce a "Professional Video Workflow Plug-In" for OS X.
The quiet addition of "Professional Video Workflow Plug-Ins" and their use in Apple's own professional applications is a tacit admission that a modular plugin architecture for working with codecs is still a necessary and vitally important step in using AVFoundation to develop professional and special-purpose video applications. Third-party developers need this capability every bit as much as apple's internal dev teams, for the very same reasons.
If a specific example would help clarify the issue, look no further than the Hap codec, which has been specifically optimized to enable the playback of large numbers of high-res video files simultaneously:
https://github.com/vidvox/hap
-- Under QuickTime, a stock retina MBP can play back 10 layers of 1080p/30fps Hap video in OS X before it starts dropping frames; more video can be played back simply by adding more/faster drives:
http://vdmx.vidvox.net/blog/hap
-- The d3 "4x4 pro"- a media server for major event production widely used by more professional touring musicians than you can shake a stick at- uses Hap to play back eight layers of 4k video in realtime:
http://www.d3technologies.com/products/4x4pro
…and to nobody's surprise, we've learned that Hap is extremely well-suited to projection mapping and dome installations, both of which are typically seen in large-scale, high-end events:
http://www.augmentedart.com/projects/red-bull-murals-a-heros-journey/
http://www.blendydomevj.com/
http://omnido.me/
None of the examples on this page can be achieved with AVFoundation in its current state- all of the above apps are either based on QuickTime (OS X and Windows) or DirectShow (Windows). Unfortunately, AVFoundation's built-in codecs are several orders of magnitude too slow for this type of application, and our inability to create a third-party codec means that this sort of performance simply cannot be realized with the framework- and this is just one concrete example.
This is an unfortunate and hopefully short-lived shortcoming, as AVFoundation appears to be capable of working with externally-produced codecs installed as "Professional Video Workflow Plug-Ins". Please publish the information necessary to allow third-party devs to produce their own "Professional Video Workflow Plug-Ins". Doing so can only help to cement OS X as the platform of choice for creative professionals with ambitious visions- visions that depend on the sort of bleeding-edge performance and flexible, useful API everyone should associate with OS X and Apple hardware.