MMC MPEG4

 Aim of this assignment is to introduce to the
possibilities that MPEG-4
 offers for the creation of interactive scenes.
To reach this aim the MPEGfamily
 will be introduced, followed by a more
detailed description of the
 possibilities of MPEG-4 and an example
scenario that could be build
 using MPEG-4.

The MPEG formats define standards for digital video and
audio services.
Since the available bandwidth for transferring the
contents is the limiting factor nowadays, the aim of the
MPEG is to define a standard that allows to reduce the
necessary bandwidth, without loosing the main benefit of
digital transmission which is transmission without losses in
quality. To achieve this the MPEG has defined methods for
compression of audio and video signals. To enhance the
standard more functionality has been added. So today the
MPEG standard covers not only a stream of video and audio
data, but also the definition of multimedia objects that
can be placed - even interactively - in a scene.

The MPEG is a group of experts that develops
standards for digital video and audio. It’s
members are working for many companies
and therefor the standards proposed by this
group are widely accepted.
3.1 MPEG-1
3.2 MPEG-2
3.3 MPEG-4
3.4 MPEG-7 and MPEG-21

3.1 MPEG-1 :
During development of MPEG-1 the aim was to
allow the storage of video and audio with a
bandwidth of up to 1.5 Mbits per second. This
would allow to store approximately a movie on a
CD. The standard was approved in 1992 and has
been a great success. A very well known part of
this standard is MP3. This allows to compress
music to 10 percent of it’s size using physical
properties (or imperfections) of the human ear.
The reduced size allows fast distribution over the
Internet which is a problem for the right holders.
MPEG-4 tries to cope with this problem by
introducing possibilities for DRM.

3.2 MPEG-2:
Two years later in 1996 MPEG-2 was approved.
MPEG-2 is today’s standard for a broad number
of applications of which the main are digital
television and the DVD. The MPEG-2 standard is
not only implemented in software, but also in
hardware. This allows the exchange between a
range of systems. For example video can be
directly coded to MPEG-2 and then be viewed
with a computer or a digital video recorder.
Today a hole industry is based on MPEG-2. A
huge amount of money is turned over in
connection with MPEG-2.

3.3 MPEG-4:
MPEG-3 does not exist since during the development it was
recognized that MPEG-2 was already fulfilling the needs of
HDTV5. So MPEG-2 was extended and MPEG-3 was skipped.
This fact is the origin of the curios numbering of the
following MPEG standards. The development of MPEG-4
was started in 1993 and is still ongoing. The first two
versions have be produced. The versions 3, 4 and 5 are
subject of current development. According to [1] MPEG-4
builds on theproven success of three fields:
1. Digital television;
2. Interactive graphics applications (synthetic content);
3. Interactive multimedia (World Wide Web, distribution of
and access to content)
MPEG-4 provides the standardized technological elements
enabling the integration of the production, distribution
and content access paradigms of the three fields.

3.4 MPEG-7 and MPEG-21:
MPEG-7 is a standard for describing
multimedia content data. It is not aimed at
any one application in particular; rather, the
elements that MPEG-7 standardizes support
as broad a range of applications as possible.
The vision for MPEG-21 is to define a
multimedia framework to enable transparent
and augmented use of multimedia resources
across a wide range of networks and devices
used by different communities.

This following subsections will cover the main points of MPEG-46.
Based on those the following section will show an example how
the possibilities of MPEG-4 can be used.
4.1 Audio:
MPEG 4 supports natural and synthesized sounds. Both can be
parted in general audio signals and speech only signals. All those
signals can have variable bit rates to be adjustable to the the
available transmission channel..The quality reaches from
intelligible speech up to high quality multichannel radio. The
most interesting feature is the support for TTS. This allows to
only transmit the text itself that is much smaller that a recorded
version. This text can be somewhere in a range from pure text to
text with additional information about the gender, age, dialect
and pronunciation. An important feature is the possibility to
synchronize the sound with the actual picture that is presented
to the user. The second important feature is the scalability of
audio signals. This can be done by parsing the source before
transferring to save bandwidth or at the decoders site to adjust
the sound to the sound system of the user.

4.2 Visual:
The visual content of MPEG-4 can be parted in
different objects. Apart from the classical
moving pictures possible objects are still 2D
images that may be a background or 3D objects
that can be placed in the foreground. Those
objects can be composed to larger groups.
Another possible object is an animated face. In
combination with TTS for example complete
synthesized news can be realized. Like the TTS
encoder the face animator can be customized. It
is possible to use a completely synthesized face
or a face that consists of a texture map where
the textures may come from a real person.

4.3 Combining audio and visual
objects:
Unlike it’s predecessors MPEG-4 is not only a
linear stream of data that is displayed to the end
user. The stream consists of multi media objects
that are placed in a three dimensional space.
Objects in this space may be grouped together to
a complete scene. An example of this van be
seen in section 5. So the end users application
has to calculate a resulting image and sound that
is presented to the user. Having all the objects
separated from each other interactivity can be
added.

4.4 Interactivity:
The user may change his view and listening
point. The video and sound is then
recalculated with the user’s new
coordinates. It is possible for example to
revolve a scene to see more details. Other
interactions may be like in adventure games
to activate objects by clicking on them. This
feature can be very useful in educational
programs to allow the users explore a topic
on their own.

4.5 Profiles:
Profiles are used to adjust the implementation to
the needs of an application. The profiles are
subsets of a complete implementation of all
defined standards in MPEG-4. According to the
user’s needs only a limited part of the MPEG-4
standard has to be implemented. If the
implementation is within a specific profile it’s
conform to MPEG-4 even if it may implement not
all methods for visual objects. A PDA or mobile
phone is an example for such a restricted device
since the computational power of such devices
are quiet restricted. So the focus will be on the
quality of the sound.

4.6 Intellectual property
management :
Since it is important to have possibilities to identify and protect
intellectual property MPEG-4 works on the definition of syntax
and tools to support this[3]. In MPEG-4 there exist possibilities to
store unique identifiers of media objects. These identifiers can
either be key-value pairs that contain for example
>>composer<</>>John Smith<< or numbers that are issued by
ISAN9, ISRC10 or others. By assigning each object it’s own
identifier, it is possible to protect only parts of the content and
leave other parts for free use. Additionally MPEG-4 offers a
standardized interface to use systems that control access to
intellectual property. This doesn’t mean that MPEG-4 protects
the intellectual property itself, but it provides the possibility to
insert information about intellectual property during authoring
and to retrieve this information at the end user’s application.

This section will show how MPEG-4 may be used. For this a
scenario of a possible application will be created and the
methods and possibilities of MPEG-4 will be shown.
5.1 The scenario:
The scenario is a news broadcast on digital television. The
scene is illustrated in the below diagram. The news reader
is filmed in front of a ’blue screen’. Then he’s projected in
front of a still image. On the left side different
contributions are inserted. Possible contributions can be a
small film or another still image. Another possibility would
be to animate a face of a reporter could be animated
using textures from pictures of him. This could be useful if
only a telephone line is available to transmit the news
from regions with weak infrastructure. It would even be
possible to let the end user’s system create the speech
with a TTS decoder.

 3D video
 Augmented reality
 Telepresence
 Scientific visualization
 Virtual reality
 …

The room is generated in computer

What has not been covered in this assignment is
the problematic use fee. Another point that was
not covered is the delivery of streaming data and
it’s according layers. MPEG-4 offers great
possibilities for the future. The idea of
interactive scenes is very attractive. But the
standard will be useless until it’s in products that
can be sold on the mass market. What will help
to introduce MPEG-4 faster is the possibility to
manage the rights of the authors. This is a major
requirement nowadays since the music and
movie industry has neglected this topic a long
time and had concentrated on complaining about
the users using the possibility to copy the
contents without loss.

MMC MPEG4

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MMC MPEG4