[opendtv] Re: Confusion about MPEG-4 AVC within MPEG-2 TS
- From: Craig Birkmaier <craig@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Fri, 11 Feb 2005 08:31:16 -0500
At 12:29 PM +0530 2/11/05, Prashant Desai wrote:
>Hello All
> thanks a lot to all of the members on this lists , for all the
>help & guidence that you guys have provided to me , i would like to
>know following things WRT MPEG-4 Part to and MPEG-2
>
>
>1) We came to know from few companies thats are dealing in the MPEG
>domain that
> MPEG-4 Part 10 content can be transported over IP by
>encapsulating the same with in the MPEG-2 transport stream , is
>this true ? if it's true then please guide me on
>
>To decode this MPEG-4 Part 10 content which is encapsulated with in
>the MPEG-2 TS do we require both MPEG-2 and MPEG-4 part 10 decoder
>on the IP Set Top BOX ? if so
> then do we need to pay for the royalty for both MPEG-2 and MPEG-4
>part 10 ? for the content etc ?
The MPEG-2 transport stream standard is a unique stand-alone product.
It has NOTHING to do with the content of the packets it carries, just
as TCP/IP knows nothing about the packets of bits that it delivers.
The main purpose of MPEG-2 transport standard was to create a
transport protocol that is optimized for the larger packet sizes than
are typically found in digital video distribution applications
(TCP/IP and most telecommunications standards use smaller packet
sizes that may not match up well with the typical packet sizes for
MPEG-2 and MPEG-4 content. There are also some features that have
been optimized to announce the services that are being carried; these
services tend to be video centric, but may also include data services.
Royalties for the MPEG-2 transport standard are separate from those
of the audio and video streams that are being transported. Early in
the ISO/MPEG work on MPEG-4 it was determined (presumably by the
people who invented and collect royalties on MPEG-2 TS) that it would
be desirable to create a mapping for MPEG-4 content into the MPEG-2
transport protocol. This would allow system operators using MPEG-2 TS
to migrate to, or add, MPEG-4 content along side MPEG-2 content.
MPEG-4 does NOT depend on MPEG-2 transport. although this is one of
the standards that can be used to deliver MPEG-4 content. The
following is from an overview of the MPEG-4 standard by Rob Koenen,
that can be viewed at:
http://www.chiariglione.org/mpeg/standards/mpeg-4/mpeg-4.htm#3.3
3.1 Transport
In principle, MPEG-4 does not define transport layers. In a number of
cases, adaptation to a specific existing transport layer has been
defined:
* Transport over MPEG-2 Transport Stream (this is an amendment to
MPEG-2 Systems)
* Transport over IP (In cooperation with IETF, the Internet
Engineering Task Force)
3.2 DMIF
DMIF, or Delivery Multimedia Integration Framework, is an interface
between the application and the transport, that allows the MPEG-4
application developer to stop worrying about that transport. A single
application can run on different transport layers when supported by
the right DMIF instantiation.
MPEG-4 DMIF supports the following functionalities:
* A transparent MPEG-4 DMIF-application interface irrespective of
whether the peer is a remote interactive peer, broadcast or local
storage media.
* Control of the establishment of FlexMux channels
* Use of homogeneous networks between interactive peers: IP, ATM,
mobile, PSTN, Narrowband ISDN.
* Support for mobile networks, developed together with ITU-T
* UserCommands with acknowledgment messages.
* Management of MPEG-4 Sync Layer information.
So to answer your question, there is no requirement to use MPEG-2
transport. For your application MPEG-2 transport may not be the best
solution, as it is likely that most of your physical infrastructure
will be based on TCP/IP - e.g. servers, routing, and client devices.
>
>2) what are the other options to transport MPEG-4 Part 10 content
>over IP transport ? apart from encapsulating it within the MPEG-2
>TS ? cant we directly transport it over IP without using MPEG-2 TS
>?
Just encapsulate the MPEG-4 content in IP packets. There is no need
or reason to use MPEG-2 transport within another transport.
>
>3) As far as the service provider of IPTV is concern i think
>MPEG-4 licensing is far more cheaper compared to the MPEG-2 , is
>this statement true or false ? why ? what are things that service
>provider is required to considered while estimating the cost of
>deployment thats related to MPEG-2 and MPEG-4 part 10
There is no clear answer to this question. It will depend on what you
are delivering. The decoder royalties are significantly lower for AVC
than for MPEG-2, but many applications are subject to encoder
royalties and/or use fees. These additional royalties may add up to
more than the decoder royalty for MPEG-2. But royalties are only one
consideration. Efficient use of bandwidth can more than make up for
royalty costs. If you are dedicating a portion of your network to
VOD, then MPEG-4 part 10 will allow you to deliver perhaps 2-3 times
the number of streams.
Regards
Craig Birkmaier
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