Files and Storage Formats - A Practical Guide to Video and Audio Compression - page 290

Value

Key Length

K L V K L V K L V

Figure 16-8 Nested KLV fragments.

data. Trials have been conducted at IBC and NAB for several years now and the interop-
erability is working very well.
Although this is a professional format aimed at broadcasters and high-end produc-
tion companies, this sort of technology generally filters down to the semi-professional
marketplace over time. MXF could also be very useful for exchanging material between
media servers and desktop editing systems in the high-end domestic, educational, and
corporate TV marketplace. MXF is going to be a very useful and important format. There
is more information at the Pro-MPEG , MXF, and AAF Web sites. Snell & Wilcox have
released the free MXF Express SDK toolkit for software developers to use when running
interoperability testing. The SDK is available at their web site.
Recent developments include the AAF Edit Protocol, which allows the separation of
edit decisions from the media content. This is somewhat akin to the reference movie tech-
nique that QuickTime supports, which is core technology within iMovie.

16.7 ASF Files

These are the files that are used to store Windows Media content. Sometimes they are
referred to as Windows Media Files but this is not always strictly true because other media
can be stored in them. The Advanced Systems Format file container stores the following
kinds of content in one file:

Audio

●

Multi bit-rate video

●

Metadata

●

Index tables

●

Script commands

●

URLs

●

Closed captioning

●

Pro-MPEG: http://www.pro-mpeg.org/
MXF: http://mxf.info/
AAF Association: http://www.aafassociation.org/
Snell & Wilcox: http://www.snellwilcox.com/
EBU: http://www.ebu.ch/
SMPTE: http://www.smpte.org/