Re: [MMUSIC] [AVT] spatial-resolution parameter for RFC 3984bis

["Even, Roni" <[e-mail]>]

Ingemar,

ForH.264 the level parameter defines the maximum FS (frame size) in
macro blocks. The image can not be bigger than that since it specify the
maximum display buffer on the receiver. There is a parameter that
overrides it maxFS that allows the receiver to say that he can support
larger picture but then the level parameter maxmbps (max macro blocks
per second) will limit the frame rate. So For h.264 you cannot give
picture size bigger then level or maxFS

 

For H.263 you either specify maximum resolution using the parameters in
RFC 4629 or the level in table X.2 in H.263.

Text from H.263

Custom picture formats can have a custom pixel aspect ratio as described
in Table 3, if the custom pixel aspect ratio use is first negotiated by
external means. Custom picture formats can have any number of lines and
any number of pixels per line, provided that the number of lines is
divisible by four and is in the range [4, ... , 1152], and provided that
the number of pixels per line is also divisible by four and is in the
range [4, ... , 2048]. For picture formats having a width or height that
is not divisible by 16, the picture is decoded in the same manner as if
the width or height had the next larger size that would be divisible by
16 and then the picture is cropped at the right and the bottom to the
proper width and height for display purposes only.

Table 3/H.263 - Custom pixel aspect ratios

Pixel aspect ratio

Pixel width:Pixel height

Square

1:1

CIF

12:11

525-type for 4:3 picture

10:11

CIF for 16:9 picture

16:11

525-type for 16:9 picture

40:33

Extended PAR

m:n, m and n are relatively prime

All decoders and encoders shall be able to operate using the CIF picture
clock frequency. Some decoders and encoders may also support custom
picture clock frequencies. All decoders shall be able to operate using
the sub-QCIF picture format. All decoders shall also be able to operate
using the QCIF picture format. Some decoders may also operate with CIF,
4CIF or 16CIF, or custom picture formats. Encoders shall be able to
operate with one of the picture formats sub-QCIF and QCIF. The encoders
determine which of these two formats are used, and are not obliged to be
able to operate with both. Some encoders can also operate with CIF,
4CIF, 16CIF, or custom picture formats.

 

 

For H.261  there is no support for arbitrary picture size (CIF is the
largest) see RFC 4587

So in the general case there should be a way to reject the request and
maybe give the supported resolution, still it will be wrong to use this
attribute for H.261

Roni

 

From: Ingemar Johansson S [mailto:[e-mail]] 
Sent: Wednesday, July 30, 2008 12:23 PM
To: [e-mail]; Even, Roni
Cc: Randell Jesup; [e-mail]; [e-mail]; [e-mail]
Subject: RE: RE: [MMUSIC] [AVT] spatial-resolution parameter for RFC
3984bis

 

Hi

 

If I understand your email correctly we will, with the constructed SDP's
below, have the potential issue that imageattr may offer combinations (x
and y resoluions) that are not allowed for a given profile level ID. The
solution I see is that the profile levels provides with an upper (maybe
also a lower?) limit.

 

For instance if we have some (really wierd) imageattr like

a=imageattr:97 [x=[128:16:1920], y=[96:16:1280],par=[1.1 1.3]]

and the profile levels only supports a resolution up to 352x288 , the
latter limitation will apply which means that the imageattr should
infact be interpreted as

a=imageattr:97 [x=[128:16:352], y=[96:16:288],par=[1.1 1.3]]

 

This is not written anywhere in the draft and I don't right now know if
this will hold in the general case, please comment.

 

/Ingemar

 

 

________________________________

From: Kyunghun Jung [mailto:[e-mail]] 
Sent: den 30 juli 2008 00:54
To: Even, Roni
Cc: Randell Jesup; Ingemar Johansson S; [e-mail];
[e-mail]; [e-mail]
Subject: Re: RE: [MMUSIC] [AVT] spatial-resolution parameter for RFC
3984bis

	Thank you Mr. Even Roni for the information. 

	 

	 We would like to ask experts in MMUSIC and AVT to pay a special
interest to the relationship

	between imageattr and config/sprop-parameter-set. How to stack
the set of information in the SDP offer

	will influence the session setup.

	 

	For example, suppose imageattr specifies image sizes over
multiple levels. The following form might be necessary.

	 m=video 49154 RTP/AVPF 99

	b=AS:48

	b=RS:0

	b=RR:2500

	a=rtpmap:99 MP4V-ES/90000

	a=imageattr:99 [x=x1,y=y1] [x=x2,y=y2] [x=x3,y=y3]

	a=fmtp:99 profile-level-id=a; \

	   config=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_1 

	a=fmtp:99 profile-level-id=b; \

	   config=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_2 

	a=fmtp:99 profile-level-id=c; \

	   config=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_3 

	 

	In case imageattr specifies image sizes within a single level.

	a=imageattr:99 [x=x1,y=y1] [x=x2,y=y2] [x=x3,y=y3]

	a=fmtp:99 profile-level-id=8

	a=fmtp:99 config=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_1

	a=fmtp:99 config=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_2

	a=fmtp:99 config=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_3

	 

	The above forms are only basic possibilities and more systematic
design and suggestion are 

	requested from MMUSIC and AVT experts.

	 

	Have a nice meeting at Dublin!

	Kyunghun Jung

	 

	
	------- Original Message -------
	Sender : Even, Roni<[e-mail]>
	Date : 2008-07-30 00:13 (GMT+09:00)
	Title : RE: [MMUSIC] [AVT] spatial-resolution parameter for RFC
3984bis
	
	Hi, 
	First of all, ITU-T documents in pdf format are free at 
	http://www.itu.int/rec/T-REC/e 
	
	As for custom format inH.263. RFC 4629 section 8.1.1 had the
custom 
	resolution, no relation to specific level. 
	
	CUSTOM: Specifies the MPI (Minimum Picture Interval) for a 
	      custom-defined resolution.  The custom parameter receives
three 
	      comma-separated values, Xmax, Ymax, and MPI.  The Xmax and
Ymax 
	      parameters describe the number of pixels in the X and Y
axis and 
	      must be evenly divisible by 4.  The permissible values for
MPI are 
	      integer values from 1 to 32, which correspond to a maximum
frame 
	      rate of 30/(1.001 *the specified value). 
	
	Also note the next sentence 
	
	      A system that declares support of a specific MPI for one
of the 
	      resolutions SHALL also implicitly support a lower
resolution with 
	      the same MPI. 
	
	Roni Even 
	
	> -----Original Message----- 
	> From: Randell Jesup [mailto:[e-mail]] 
	> Sent: Tuesday, July 29, 2008 5:08 PM 
	> To: [e-mail] 
	> Cc: Ingemar Johansson S; [e-mail]; Even, Roni; Ye- 
	> [e-mail]; [e-mail] 
	> Subject: Re: [MMUSIC] [AVT] spatial-resolution parameter for
RFC 
	> 3984bis 
	>  
	> Kyunghun Jung <[e-mail]> writes: 
	> >Some clarifications are as follows. 
	> > 
	> > 
	> > 
	> >>So far as I know (and I didn't recheck), H.263 only allows
for 
	> resolutions 
	> >>specified in the fmtp (though QCIF and CIF are I think
required). 
	If 
	> you 
	> >>want 344x288, you need to add a CUSTOM resolution to the
fmtp line. 
	> And 
	> >>the mpi must be an integer in the fmtp.  Now, if both sides
use 
	this, 
	> then 
	> >>those restrictions could be relaxed. 
	> > 
	> >In H.263, Custom Picture Format (CPFMT) is supported at level
50 or 
	> >higher. 
	> > 
	> >3GPP requires only level 45 of H.263 for its mobile video
telephony 
	> and 
	> >whether its level is increased further is doubtful. In other
words, 
	> MPEG-4 
	> >and H.264 are expected to utilize imageattr a lot. 
	>  
	> I think you misunderstand my comment.  I was referring the the
SDP 
	fmtp 
	> line for H.263, where custom resolutions (other then CIF, etc)
can be 
	> specified. 
	>  
	> Since the ITU specs are a pain to come by (I think I have an
old H.263 
	> and 
	> Annexes stashed somewhere, but it isn't handy at the moment,
from 
	> home), I 
	> can't easily look up the Annex X profile/level stuff; I just
know how 
	> the 
	> SDP works from the IETF spec.  (I tried to look it up online -
Ugh, 
	> requires TIES account.  The ITU appears to not want anyone
except 
	large 
	> companies to implement their specs.)  :-( 
	>  
	> It sounds like "CUSTOM" isn't of any use for many scenarios. 
	>  
	> In any case, I was responding to Ingemar's example that used
custom 
	> resolutions in H.263. 
	>  
	> >Sincerely yours, 
	> > 
	> >Kyunghun Jung 
	> > 
	> > 
	> > 
	> >------- Original Message ------- 
	> >Sender : Randell Jesup<[e-mail]> 
	> >Date : 2008-07-29 00:49 (GMT+09:00) 
	> >Title : Re: [MMUSIC] [AVT] spatial-resolution parameter for
RFC 
	> 3984bis 
	> > 
	> >"Ingemar Johansson S" <[e-mail]>
writes: 
	> >>To answer Roni's and Ye-Kui's comments I believe that the
image 
	> attribute 
	> >>can be used for 3. However, looking in perspective I am not
longer 
	> sure 
	> >>that the possibility to specify a framerate range makes
sense as it 
	> does 
	> >>not connect  too wellto reality when it comes to e.g H.264
which 
	> talks 
	> >>about macroblocks per second. The conclusion is then that
the 
	> framerate 
	> >>(or MBs) is determined from the fmtp line. 
	> >>This means that if the imageattr specifies a large offered
range the 
	> frame 
	> >>rate is limited by what is possible for the given preferred 
	> resolution. 
	> >> 
	> >>As an example, consider H.263 with the fmtp line 
	> >> CIF=4;QCIF=3;SQCIF=2; 
	> >>the imageattr may then be specified as 
	> >>a=imageattr:97 [x=[128:8:352],y=[96:8:288],par=[1.2,1.3]] 
	> >>If the receiver prefers the resolution 344x288 (slightly
less than 
	> CIF) the maximum frame rate would be 30/(1.0001*4) ~ 7.5Hz. 
	> >>If the prefered resolution is 160x128 (slightly less than
QCIF) then 
	> the max frame rate is 30/(1.0001*3) Hz and so on. 
	> > 
	> >So far as I know (and I didn't recheck), H.263 only allows
for 
	> resolutions 
	> >specified in the fmtp (though QCIF and CIF are I think
required).  If 
	> you 
	> >want 344x288, you need to add a CUSTOM resolution to the fmtp
line. 
	> And 
	> >the mpi must be an integer in the fmtp.  Now, if both sides
use this, 
	> then 
	> >those restrictions could be relaxed. 
	> > 
	> >>For the H.264 case the frame rate depending of the preferred
image 
	> size 
	> >>would be limited according to the maximum framerate
repending on the 
	> max 
	> >>MBs and the resolution given in table A-6 in the H.264 spec.
For 
	> instance 
	> >>for level 2 an image size of 344x280 which is less than CIF
but 
	> larger 
	> >>than QVGA would yield a max frame rate of 30Hz. 
	> > 
	> >My suggestion would be for this to express preferences within
the 
	> normal 
	> >negotiated resolution and framerate space.  i.e for 264 the
level and 
	> >max-fs and max-mbps would determine the *maximum* frame and
framerate 
	> >supported, but this would be used to decide what to actually
send. 
	> > 
	> >See my original email below -- look for: 
	> > "I would suggest instead (and did in the thread back in
March)" 
	> > 
	> >> 
	> >>Would this distincion between framerate (or MBs) and
preferred image 
	> size work? 
	> >> 
	> >>/Ingemar 
	> >> 
	> >> 
	> >> 
	> >>> -----Original Message----- 
	> >>> From: Even, Roni [mailto:[e-mail]] 
	> >>> Sent: den 28 juli 2008 11:32 
	> >>> To: [e-mail]; Ingemar Johansson S;
[e-mail] 
	> >>> Cc: [e-mail] 
	> >>> Subject: RE: [AVT] spatial-resolution parameter for RFC
3984bis 
	> >>> 
	> >>> Hi, 
	> >>> I think that we have to be clear about the usage of the
parameter 
	> >>> 
	> >>> 1. Announce sending of the specific resolution - just 
	> >>> resolution 2. Request a specific resolution - Receiver
wants 
	> >>> a specific resolution 3. Negotiate available resolutions -

	> >>> The offer says, I can do CIF, QCIF, 1080P,... here it may 
	> >>> dependent in H.263 and H.261 on the frame rate while in
H.264 
	> >>> the limit is in the macroblocks per second which will
specify 
	> >>> the maximum frame rate. The reason for this offer is
because 
	> >>> it offers the operation points that the offerer can have.
The 
	> >>> level parameter in H.263 and H.264 gives a maximum but
does 
	> >>> not imply support for any resolution that the answer would

	> >>> like to receive that falls within the range of the level. 
	> >>> 
	> >>> I think the img attribute address 1 and 2, I am not sure
about 3 
	> >>> 
	> >>> Roni Even 
	> >>> 
	> >>> > -----Original Message----- 
	> >>> > From: [e-mail]
[mailto:[e-mail]] 
	> >>> > Sent: Monday, July 28, 2008 1:11 PM 
	> >>> > To: [e-mail]; [e-mail] 
	> >>> > Cc: Even, Roni; [e-mail] 
	> >>> > Subject: RE: [AVT] spatial-resolution parameter for RFC
3984bis 
	> >>> > 
	> >>> > 
	> >>> > Interesting! I just wrote the following email, planned
to 
	> >>> send to the 
	> >>> > MMUSIC mailing list. Now this comes only to AVT. Feel
free 
	> >>> to forward 
	> >>> > it to MMUSIC (don't know whether it is allowed to cross
posting) 
	> or 
	> >>> > let me to send that, if needed. 
	> >>> > 
	> >>> > 
	> >>> > After a reading of this draft
(draft-johansson-mmusic-image- 
	> >>> > attributes), I think the sprop-spatial-resolution
parameter in 
	> the 
	> >>> > RFC3984bis can go. It is completely covered by
imageattr. 
	> >>> > 
	> >>> > A couple of comments to
draft-johansson-mmusic-image-attributes. 
	> >>> > 
	> >>> > - It would be helpful to introduce the methods in
payload 
	> >>> format specs 
	> >>> > for H.261, H.263 and H.264. In particular, for the one I
am 
	> >>> familiar 
	> >>> > with (i.e. H.264), I am not sure how exactly image size 
	> >>> together with 
	> >>> > frame rate is negotiated. 
	> >>> > 
	> >>> > - Re the following paragraph, I am not sure which
parameters are 
	> >>> > "similar features" and MUST NOT be specified in
imageattr. 
	> >>> Basically, 
	> >>> > H.264 sequence parameter set (SPS)may contain all 
	> >>> information relating 
	> >>> > to what may be included in imageattr according to the
curent 
	> draft. 
	> >>> > For example, the VUI part of SPS may even contain frame 
	> >>> rate related 
	> >>> > synatx elements. 
	> >>> >    o  Conflict with sprop-parameter-set: H.264 defines
the 
	sprop- 
	> >>> >       parameter-set which may define features that are 
	> >>> defined in this 
	> >>> >       draft.  To avoid conflicts, sessions that use the 
	imageattr 
	> >>> >       attribute MUST NOT specify similar features in 
	> >>> sprop-parameter- 
	> >>> >       set. 
	> >>> > 
	> >>> > BR, YK 
	> >>> > 
	> >>> > >-----Original Message----- 
	> >>> > >From: ext Ingemar Johansson S 
	> >>> > >[mailto:[e-mail]] 
	> >>> > >Sent: Monday, July 28, 2008 1:04 PM 
	> >>> > >To: [e-mail] 
	> >>> > >Cc: Wang Ye-Kui (Nokia-NRC/Tampere); Even, Roni;
Randell Jesup 
	> >>> > >Subject: Re: [AVT] spatial-resolution parameter for RFC
3984bis 
	> >>> > > 
	> >>> > >Hi 
	> >>> > > 
	> >>> > > 
	> >>> > >Given the discussion below I really wonder if it is not
a 
	better 
	> >>> > >alternative to specifiy preferred image sizes using a
dedicated 
	> >>> > >(generic) SDP attribute. 
	> >>> > >Even though this is solved in some way in 3984bis we
still have 
	> to 
	> >>> > >provide with a solution for MPEG-4 or H.263 later on. 
	> >>> > >I drafted a proposed solution for an "a=imageattr"
attribute 
	> some 
	> >>> > >time ago that may be useful 
	> >>> > >http://tools.ietf.org/id/draft-johansson-mmusic-image- 
	> attributes- 
	> >>> > 01.txt 
	> >>> > >The draft provides with a solution that may work but
lacks a 
	> >>> > >requirement spec to outline exactly what the attribute 
	> >>> aims for. Also 
	> >>> > >extra work is needed to avoid conflicts with related 
	> >>> payload format 
	> >>> > >parameters. 
	> >>> > > 
	> >>> > >Regards 
	> >>> > >Ingemar 
	> >>> > > 
	> >>> > > 
	> >>> > >============================= 
	> >>> > >To: <Ye-Kui.Wang at nokia.com> 
	> >>> > >Subject: Re: [AVT] spatial-resolution parameter for RFC
3984bis 
	> >>> > >From: Randell Jesup <rjesup at wgate.com> 
	> >>> > >Date: Mon, 14 Jul 2008 09:35:18 -0400 
	> >>> > >Cc: roni.even at polycom.co.il, avt at ietf.org 
	> >>> > > 
	> >>> > ><Ye-Kui.Wang at nokia.com> writes: 
	> >>> > >>The resolution must be restricted by the level part of

	> >>> > >>profile-level-id and max-fs. Therefore, if a
configuration is 
	> agreed 
	> >>> > >>(or agreeable), then the answerer must request a
resolution 
	> under 
	> >>> > >>the constraint, and the offerer must accept the
request as 
	long 
	> as 
	> >>> > >>it meets the restriction.  This is similar as
sprop-parameter- 
	> sets, 
	> >>> > >>as long as it is complaint with the agreed (or
agreeable) 
	> >>> > >>configuration, the other side must accept it. 
	> >>> > > 
	> >>> > >I would suggest instead (and did in the thread back in
March): 
	> that 
	> >>> > >as a receiver property, it is the *preferred* maximum
frame 
	> size. 
	> >>> > >The receiver is required to decode and handle any size
up to 
	the 
	> size 
	> >>> > >implied by the level (and max-fs if given), but the
receiver 
	> prefers 
	> >>> > >this size (for example, it may support 1920x1080, but
only have 
	> an 
	> >>> > >LCD display that can display 1200x720, so there's no
*need* to 
	> send 
	> >>> > >it anything higher (and the encoder may prefer to avoid

	encoding 
	> more 
	> >>> > >macroblocks, especially in an MCU that shares
resources)).  In 
	> other 
	> >>> > >cases, the sender may have the stream already encoded
in 
	> different 
	> >>> > >resolutions, and this can help select the best one to
send to 
	> save 
	> >>> > >encoding (and bandwidth) resources. 
	> >>> > > 
	> >>> > >There is no requirement that the encoder scale, but if
it wants 
	> to it 
	> >>> > >can. 
	> >>> > > 
	> >>> > >It also (if I remember) provides aspect-ratio
information. 
	> >>> > > 
	> >>> > >>Would it work this way? 
	> >>> > >> 
	> >>> > >>BR, YK 
	> >>> > >> 
	> >>> > >>>-----Original Message----- 
	> >>> > >>>From: ext Even, Roni [mailto:roni.even at
polycom.co.il] 
	> >>> > >>>Sent: 14 July, 2008 10:38 
	> >>> > >>>To: Wang Ye-Kui (Nokia-NRC/Tampere); avt at ietf.org 
	> >>> > >>>Subject: RE: [AVT] spatial-resolution parameter for
RFC 
	> 3984bis 
	> >>> > >>> 
	> >>> > >>>YK, 
	> >>> > >>>Just to clarify, 
	> >>> > >>>The text on the receiver side says that this is the
requested 
	> >>> > >>>resolution, it does not address issue of negotiation,

	> >>> what will the 
	> >>> > >>>sender do if it cannot send this resolution, should
it 
	> >>> reject the 
	> >>> > >>>stream?. 
	> >>> > >>>If this is for negotiation do you except to do a new 
	> >>> offer answer 
	> >>> > >>>if the receiver wants a new resolution? 
	> >>> > >>> 
	> >>> > >>>Roni 
	> >>> > >>> 
	> >>> > >>>> -----Original Message----- 
	> >>> > >>>> From: avt-bounces at ietf.org [mailto:avt-bounces
at 
	> >>> ietf.org] On 
	> >>> > >>>> Behalf Of Ye-Kui.Wang at nokia.com 
	> >>> > >>>> Sent: Sunday, July 13, 2008 7:57 PM 
	> >>> > >>>> To: avt at ietf.org 
	> >>> > >>>> Subject: [AVT] spatial-resolution parameter for RFC
3984bis 
	> >>> > >>>> 
	> >>> > >>>> 
	> >>> > >>>> Concluded from the discussions in the email threads
listed 
	> >>> > >below, I 
	> >>> > >>>> added a new parameter, spatial-resolution, to the
RFC 
	> >>> > >3984bis draft 
	> >>> > >>>> (which will be submitted by tomorrow): 
	> >>> > >>>> 
	> >>> > >>>> http://www.ietf.org/mail- 
	> archive/web/avt/current/msg09425.html 
	> >>> > >>>> http://www.ietf.org/mail- 
	> archive/web/avt/current/msg09650.html 
	> >>> > >>>> 
	> >>> > >>>> The parameter is specified as follows (basically as
Randell 
	> >>> > >>>> suggested in 
	> >>> > >>>> 
	> >>>
http://www.ietf.org/mail-archive/web/avt/current/msg09429.html). 
	> >>> > >>>> 
	> >>> > >>>> spatial-resolution: 
	> >>> > >>>> This parameter MAY be used to indicate the maximum
spatial 
	> >>> > >>>> resolution of a NAL unit stream or the preferred
spatial 
	> >>> > >resolution 
	> >>> > >>>> of a receiver. 
	> >>> > >>>> The value is a base16 [6] (hexadecimal)
representation of 
	> the 
	> >>> > width 
	> >>> > >>>and 
	> >>> > >>>> height of the spatial resolution, in pixels,
separated 
	> >>> by a comma. 
	> >>> > >>>> 
	> >>> > >>>> Usage in SDP offer/answer: 
	> >>> > >>>> - When "a=sendrecv" or no direction attribute is
used, 
	> >>> > >>>> "spatial-resolution" indicates both the maximum
spatial 
	> >>> > >>>> resolution of the stream sent by the declaring
entity and 
	> the 
	> >>> > >preferred spatial 
	> >>> > >>>> resolution for receiving a stream. 
	> >>> > >>>> - When "a=sendonly", "spatial-resolution" indicates
the 
	> maximum 
	> >>> > >>>spatial 
	> >>> > >>>> resolution of the outgoing stream. 
	> >>> > >>>> - When "a=recvonly", "spatial-resolution" indicates

	> >>> the preferred 
	> >>> > >>>> spatial resolution for receiving a stream. 
	> >>> > >>>> 
	> >>> > >>>> Comments are welcome. 
	> >>> > >>>> 
	> >>> > >>>> BR, YK 
	> >>> > >>>> _______________________________________________ 
	> >>> > >>>> Audio/Video Transport Working Group avt at ietf.org

	> >>> > >>>> https://www.ietf.org/mailman/listinfo/avt 
	> >>> > >>> 
	> >>> > >>_______________________________________________ 
	> >>> > >>Audio/Video Transport Working Group 
	> >>> > >>avt at ietf.org 
	> >>> > >>https://www.ietf.org/mailman/listinfo/avt 
	> >>> > > 
	> >>> > > 
	> >>> > >-- 
	> >>> > >Randell Jesup, Worldgate (developers of the Ojo 
	> >>> videophone), ex-Amiga 
	> >>> > >OS team rjesup at wgate.com "The fetters imposed on 
	> >>> liberty at home 
	> >>> > >have ever been forged out of the weapons provided for 
	> >>> defence against 
	> >>> > >real, pretended, or imaginary dangers from abroad." 
	> >>> > >        - James Madison, 4th US president (1751-1836) 
	> >>> > > 
	> >>> > >******************************************* 
	> >>> > >Ingemar Johansson 
	> >>> > >Senior Research Engineer, IETF "nethead" 
	> >>> > >EAB/TVP - Multimedia Technologies 
	> >>> > >Ericsson Research Ericsson AB 
	> >>> > >Box 920 S-971 28 Luleaa, Sweden 
	> >>> > >Tel: [phone] 
	> >>> > >ECN: 850-43042 
	> >>> > >ECC: 850-43074 
	> >>> > >Mobile: [phone] 
	> >>> > >******************************************* 
	> >>> > > 
	> >>> 
	>  
	>  
	> -- 
	> Randell Jesup, Worldgate (developers of the Ojo videophone),
ex-Amiga 
	> OS team 
	> [e-mail] 
	> "The fetters imposed on liberty at home have ever been forged
out of 
	> the weapons 
	> provided for defence against real, pretended, or imaginary
dangers 
	from 
	> abroad." 
	>         - James Madison, 4th US president (1751-1836) 

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