I found this section in the Mac Developer Library that discusses the AV framework and technologies for OS X Mavericks:
"The following sections highlight changes to frameworks and technologies in OS X v10.9.
New Frameworks
The following frameworks have been added in OS X v10.9:
AV Kit (AVKit.framework). AV Kit is a modern API for incorporating media playback capabilities into apps. AV Kit provides view-level services for media playback, complete with user controls, chapter navigation, and support for subtitles and closed captioning. Built on the most modern OS X media technology, AV Kit is an ideal starting point for developers looking to transition their QuickTime-based applications to AV Foundation.
For more information, read AV Kit Framework Reference.
Deprecated Frameworks
From time to time, Apple adds deprecation macros to APIs to indicate that those APIs should no longer be used in active development. When a deprecation occurs, it is not an immediate end of life to the specified API. Instead, it is the beginning of a grace period for transitioning off that API and onto newer and more modern replacements. Deprecated APIs typically remain present and usable in the system for some reasonable amount of time past the release in which they were deprecated. However, active development on them ceases, and the APIs receive only minor changes to accommodate security patches or to fix other critical bugs. Deprecated APIs may be removed entirely from a future version of the operating system.
As a developer, it is important that you avoid using deprecated APIs in your code as soon as possible. At a minimum, new code you write should never use deprecated APIs. And if you have existing code that uses deprecated APIs, you should update that code as soon as possible. Fortunately, the compiler generates warnings whenever it spots the use of a deprecated API in your code. You can use those warnings to track down and remove all references to those APIs.
The following frameworks are deprecated in OS X v10.9:
Instant Message framework
QuickTime framework
QTKit framework (except for QTMovieModernizer)
The Instant Message framework is superseded by the Social framework. Because the Messages application no longer provides functionality that the Instant Message framework requires, in OS X v10.9 and later this framework always returns an empty buddy list.
The QuickTime and QTKit frameworks are superseded by AV Kit and AV Foundation. You can learn more about transitioning to AV Kit and AV Foundation by reading Transitioning QTKit Code to AV Foundation.
The newly added QTMovieModernizer class in QTKit provides support for converting media encoded using older codecs into modern formats that are forward-compatible with AV Foundation.
Note: The QuickTime file format (.mov) is not deprecated. It is the primary media format in OS X and iOS, and is well supported by AV Foundation."
Source: https://developer.apple.com/library/mac/releasenotes/MacOSX/WhatsNewInOSX/Articl es/MacOSX10_9.html#//apple_ref/doc/uid/TP40013207-SW3