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MPEG-7 is a metadata standard to describe multimedia content. It
allows to describe different aspect of a multimedia document
ranging from structural ones (scenes, shots, transitions),
descriptive (colors, histograms, level of noise), legal (author,
MPEG-21 provides necessary information to create a multimedia
framework meaning tools to identify, publish, adapt and protect
From a broader point of view MPEG is defining a "multimedia
framework" where you can transmit video (MPEG2/MPEG4) or multimedia
presentation (MPEG4), that can be searched (MPEG-7), identified and
exchanged safely (MPEG-21).
Used together these standards are complementary but they can be
used of course independently. An MPEG-7 description can describe a
JPG or a GIF file and even non digital content (tapes). MPEG-21
can be used to exchange any kind of multimedia content like a GIF
file, an Mjpeg video or a smil presentation.
In order to achieve this, MPEG is extensively using XML :
- MPEG-4 : XMT-A : X3D based low level description of a multimedia
- MPEG-4 : XMT-O : SMIL based description of a multimedia content
- MPEG-7 : multimedia content description
- MPEG-21 : digital item description, terminal capabilities, aso..
In parallel to achieve efficiency MPEG defines many tools : a
compact file format (MPEG-4 file format), a flexible network
adaptation layer (MPEG-2 and MPEG-4 systems), and some streamable
compression schemes for audio (AAC, MP3, ..), video and multimedia
Moreover, the past two years MPEG designed an XML binary encoding
format called BiM. As its main features, BiM generates a very compact
representation of an XML document. The resulting binary format
includes information to considerably speed-up search (compiled). It
is streamable which means that document deltas can be send to update
a remote version of an XML document. It allows progressive download
of an XML file in order to reduce user perceived waiting time for
instance. It allows to update document at different refresh rates.
Therefore, XML is influencing MPEG in many ways. Every XML language
is designed using core XML specification (XML Schema, XPath). Even
BiM relies on XML Schema specification. Moreover, MPEG is using many
non-MPEG XML standard specifications (SMIL, X3D).
Hope it answers your questions.
> Pavithran wrote:
> Hi All,
> Can any one give real time usage of MPEG-7 and MPEG-21,
> How XML is going to influence MPEG stds,
> Thanking in advance,
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