Subject: Allocation of a stream descriptor for MPEG-2

From: Gorry Fairhurst <[email-masked]>
Date: Wed, 09 Mar 2005 08:11:23 -0600

Dear all,

The ipdvb WG of the IETF have developed a document that describes an Ultra
Lightweight Encapsulation (ULE) mechanism for the transport of IPv4 and IPv6
Datagrams and other network protocol packets directly over the ISO MPEG-2
Transport Stream as TS Private Data.

This document has now been submitted to the Internet Engineering Steering
Group (IESG) with a request for publication as an IETF Standards Track
document in the RFC series.

https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag=1163
4

At the ipdvb meeting on 7th March, the WG noted that the MPEG-2
specification requires conformant TS Multiplexes to provide Program Specific
Information (PSI) for each stream in the TS Multiplex. Other MPEG-2 based
transmission standards may also define Service Information (SI). This
information may allow Receivers and Re-multiplexors to locate a specific ULE
Stream (i.e., the PID value that carries a ULE Stream).

The WG therefore intends to apply for allocation of an appropriate code
point(s) (i.e. Descriptor / Identifier) from the relevant organisations that
co-ordinate the use of MPEG-2.

If you have experience of the procedure, or have any useful comments, or
would be willing to help develop text for an appropriate request, could you
please let me know.

Gorry Fairhurst
(ipdvb WG Chair)

---

From: Michael A Dolan <[email-masked]>
Date: Wed, 09 Mar 2005 07:14:48 -0800

Private range MPEG field values do not have an authoritative registry, but 
ATSC has informally provided an industry code point document:

http://www.atsc.org/standards/Code_Point_Registry.pdf

For format_identifier values (used in the registration descriptor), SMPTE 
is the formal ISO registrar:

http://www.smpte-ra.org/mpeg.html

Regards,

         Mike

---

From: Martin Stiemerling <[email-masked]>
Date: Wed, 09 Mar 2005 20:14:17 +0100

Hi Gorry,

As stated during the session, I'm willing to help but not familiar with the
procedure to get such code points.

  Martin

--On Mittwoch, 9. März 2005 8:11 Uhr -0600 Gorry Fairhurst 
<[email-masked]> wrote:

|
| Dear all,
|
| The ipdvb WG of the IETF have developed a document that describes an Ultra
| Lightweight Encapsulation (ULE) mechanism for the transport of IPv4 and
| IPv6 Datagrams and other network protocol packets directly over the ISO
| MPEG-2 Transport Stream as TS Private Data.
|
| This document has now been submitted to the Internet Engineering Steering
| Group (IESG) with a request for publication as an IETF Standards Track
| document in the RFC series.
|
| https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag=1
| 163 4
|
| At the ipdvb meeting on 7th March, the WG noted that the MPEG-2
| specification requires conformant TS Multiplexes to provide Program
| Specific Information (PSI) for each stream in the TS Multiplex. Other
| MPEG-2 based transmission standards may also define Service Information
| (SI). This information may allow Receivers and Re-multiplexors to locate
| a specific ULE Stream (i.e., the PID value that carries a ULE Stream).
|
| The WG therefore intends to apply for allocation of an appropriate code
| point(s) (i.e. Descriptor / Identifier) from the relevant organisations
| that co-ordinate the use of MPEG-2.
|
| If you have experience of the procedure, or have any useful comments, or
| would be willing to help develop text for an appropriate request, could
| you please let me know.
|
| Gorry Fairhurst
| (ipdvb WG Chair)
|
|
|
|
|
|
|
|
|
|

---

From: Gorry Fairhurst <[email-masked]>
Date: Fri, 11 Mar 2005 11:27:03 -0600

Thanks Mike, 

This looks like the correct thing, which registry item should we be asking
to create?

If we have support for the same type in a DVB multiplex, do you know if
there is any merit in co-ordinating this process?

Best wishes,

Gorry

---

From: Michael A Dolan <[email-masked]>
Date: Fri, 11 Mar 2005 11:33:44 -0800

By all means do it the same on all MPEG-2 transports!  To do this "right", 
you need to:

1. pick a stream_type value > 0x80 - look at the ATSC registry and find an 
unused one you like.  Then send email to ATSC telling them what you did and 
providing a link to the IETF document for reference.
2. register a format_identifier value with the SMPTE RA, such as "ULE1"
3. require transports carrying these streams put the ISO 13818-1 
registration descriptor in the PMT ES_info descriptor loop with the value 
assigned from #2
4. update the IETF document with the above information so you have 
interoperability

Steps #2 and #3 may seem a bit redundant if you pick an unused value in 
#1.  However, there is no formal registry and your "assigned" value can in 
fact be legally used by anyone else.  All of the above steps would be 
required in an ATSC transport.  DVB and ARIB may be more flexible - don't 
know.  But in any event, this is how it should be done to ensure 
unambiguous signaling of the stream containing these packets.

ISO will not assign you a value below 0x80 from 13818-1, Table 2.29 since 
they did not define the elementary stream.

As an analogy, AC-3 audio (not an ISO codec) is customarily 
stream_type=0x81 (in ATSC and DVB both), and requires the registration 
descriptor with the registered value "AC-3" in the PMT ES_info loop.

No coordination is needed if you document this in the IETF document - ATSC 
and DVB should simply do it as recommended.  If you do not document this in 
the IETF document, then someone will have to pay attention in DVB and ATSC 
both to ensure it is done the same way and documented somehow.  Better that 
you do it once.

Regards,

         Mike

---

From: Carsten Bormann <[email-masked]>
Date: Sun, 13 Mar 2005 08:45:08 +0100

On Mar 11 2005, at 20:33 Uhr, Michael A Dolan wrote:

> registration descriptor in the PMT ES_info descriptor loop with the 
> value assigned from #2

I'm not so sure about the "require" part.
"Suggest" sounds more like it.
(Not all ULE applications will require the full complexity of the 
tables.)

Gruesse, Carsten

---

From: Michael A Dolan <[email-masked]>
Date: Sun, 13 Mar 2005 14:50:07 -0800

How will you know without ambiguity that the stream contains ULE packets if 
you don't?

At 3/12/2005 11:45 PM, Carsten Bormann wrote:
>(Not all ULE applications will require the full complexity of the tables.)
>
>Gruesse, Carsten

---

From: Carsten Bormann <[email-masked]>
Date: Mon, 14 Mar 2005 00:56:09 +0100

On Mar 13 2005, at 23:50 Uhr, Michael A Dolan wrote:

> How will you know without ambiguity that the stream contains ULE 
> packets if you don't?

By previous agreement. (E.g., after renting an entire transponder 
exclusively for ULE packets.)

What I'm trying to say is that the ULE encapsulation is not dependent 
on the DVB/ATSC magic around it doing its thing (or, more precisely, is 
only dependent on it if that magic is in actual use by some component 
on the way).  So it would be a mistake for ULE to stipulate that those 
tables are maintained properly.

Or, in other words, if the DVB/ATSC magic is required to properly 
transport the ULE packets, this is not a conformance requirement on the 
ULE packets, but on the system that injects them into the DVB/ATSC 
world.

Gruesse, Carsten