Subject: [AVT] draft-ietf-avt-rtp-svc-04 base layer term

From: "Even, Roni" <[email-masked]>
Date: Thu, 3 Jan 2008 16:38:48 +0200

Hi,

In section 5.1.2 you define the base layer different from the definition in annex G of H.264. You define full base layer to be the same as annex G. I find this confusing and suggest you use different terms

Even in the draft the text is not using the new defined terms correctly. See all the usage of base layer in the text above section 5.

Also the text for full base layer is different from annex G which I find clearer since it mentions the VCL NAL units that should be used in the base layer and which should not.

I also noticed that you use base layer only in the layer definition (did you mean base of full base) so it looks redundant

Roni

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

---

From: <[email-masked]>
Date: Fri, 4 Jan 2008 02:10:21 +0200

Hi again Roni,
 
I agree with you that it would be better to use different terms than
having the same term as in the SVC coding spec but with different
meanings. This will be done the next version - and we will copy the
"base layer" definition from the SVC spec if no one disagrees. For the
current term "base layer", does anyone have a good name recommendation?
"true base layer"? "subset base layer"? "base base layer"?
 
However, I disagree that in the current draft the defined terms "base
layer" and "full base layer" are not used correctly. Besides these two
definitions themselves, in all other occuring places, they are used as
they are defined. There is one exception of "base layer" in the open
issues - but I think you did not mean that one. 
 
At last, "base layer" has been used in many places than in the
definition of Layer, wherein it is also used as it is defined. 
 
BR, YK

________________________________

	From: ext Even, Roni [mailto:[email-masked]] 
	Sent: Thursday, January 03, 2008 4:39 PM
	To: [email-masked]
	Subject: [AVT] draft-ietf-avt-rtp-svc-04 base layer term

	Hi,

	In section 5.1.2 you define the base layer different from the
definition in annex G of H.264. You define full base layer to be the
same as annex G. I find this confusing and suggest you use different
terms

	Even in the draft the text is not using the new defined terms
correctly. See all the usage of base layer in the text above section 5.

	Also the text for full base layer is different from annex G
which I find clearer since it mentions the VCL NAL units that should be
used in the base layer and which should not.

	I also noticed that you use base layer only in the layer
definition (did you mean base of full base) so it looks redundant

	Roni

---

From: Alex Eleftheriadis <[email-masked]>
Date: Fri, 4 Jan 2008 12:26:06 +0200

I am very much in support of keeping the definitions between the two  
documents fully aligned.

Specifically for the current definition of a base layer as found in  
the 04 document, and taking into account that the definition of  
"layer representation" in the SVC spec is orthogonal to the temporal  
level (i.e., it only refers to dependency_id and quality_id), we can  
use:

- base layer at the lowest temporal resolution, or

- T0 base layer

The first one appears long-ish, but it's preferrable to the very  
vague "true" or "subset". The second one appears to me to be a usable  
shorthand. Further attribution to the term "layer" would be  
inappropriate, in view of SVC's definition of a layer representation.  
There are very few instances of the term in the document anyway, so  
the long version would not be tiring to the reader.

--
Alex Eleftheriadis
Vidyo, Inc.
[email-masked]

On Jan 4, 2008, at 2:10 AM, <[email-masked]> wrote:

> Hi again Roni,
>
> I agree with you that it would be better to use different terms  
> than having the same term as in the SVC coding spec but with  
> different meanings. This will be done the next version - and we  
> will copy the "base layer" definition from the SVC spec if no one  
> disagrees. For the current term "base layer", does anyone have a  
> good name recommendation? "true base layer"? "subset base layer"?  
> "base base layer"?
>
> However, I disagree that in the current draft the defined terms  
> "base layer" and "full base layer" are not used correctly. Besides  
> these two definitions themselves, in all other occuring places,  
> they are used as they are defined. There is one exception of "base  
> layer" in the open issues - but I think you did not mean that one.
>
> definition in annex G of H.264. You define full base layer to be  
> the same as annex G. I find this confusing and suggest you use  
> different terms
>
>
>
> Also the text for full base layer is different from annex G which I  
> find clearer since it mentions the VCL NAL units that should be  
> I also noticed that you use base layer only in the layer definition  
> (did you mean base of full base) so it looks redundant
>
>
>
> Roni
>

---

From: <[email-masked]>
Date: Fri, 4 Jan 2008 13:10:34 +0200

Thanks Alex for the good names. I like "T0 base layer" more, because
this one is the mainly used term in the draft, while the "full base
layer" or "(full) base layer" (meaning base layer or full base layer) is
used only in two places, therefore short is good.
 
BR, YK

	From: ext Alex Eleftheriadis [mailto:[email-masked]] 
	Sent: Friday, January 04, 2008 12:26 PM
	To: Wang Ye-Kui (Nokia-OCTO/Tampere)
	Cc: [email-masked]; [email-masked]
	Subject: Re: [AVT] draft-ietf-avt-rtp-svc-04 base layer term

	I am very much in support of keeping the definitions between the
two documents fully aligned.  

	Specifically for the current definition of a base layer as found
in the 04 document, and taking into account that the definition of
"layer representation" in the SVC spec is orthogonal to the temporal
level (i.e., it only refers to dependency_id and quality_id), we can
use:

	- T0 base layer

	The first one appears long-ish, but it's preferrable to the very
vague "true" or "subset". The second one appears to me to be a usable
shorthand. Further attribution to the term "layer" would be
inappropriate, in view of SVC's definition of a layer representation.
There are very few instances of the term in the document anyway, so the
long version would not be tiring to the reader.

	--
	Alex Eleftheriadis
	Vidyo, Inc.
	[email-masked]

		Hi again Roni,
		 
		I agree with you that it would be better to use
different terms than having the same term as in the SVC coding spec but
with different meanings. This will be done the next version - and we
will copy the "base layer" definition from the SVC spec if no one
disagrees. For the current term "base layer", does anyone have a good
name recommendation? "true base layer"? "subset base layer"? "base base
layer"?
		 
		However, I disagree that in the current draft the
defined terms "base layer" and "full base layer" are not used correctly.
Besides these two definitions themselves, in all other occuring places,
they are used as they are defined. There is one exception of "base
layer" in the open issues - but I think you did not mean that one. 
		 
		At last, "base layer" has been used in many places than
in the definition of Layer, wherein it is also used as it is defined. 
		 
		BR, YK

			From: ext Even, Roni
[mailto:[email-masked]] 
			Sent: Thursday, January 03, 2008 4:39 PM
			To: [email-masked]
			Subject: [AVT] draft-ietf-avt-rtp-svc-04 base
layer term

			Hi,

			In section 5.1.2 you define the base layer
different from the definition in annex G of H.264. You define full base
layer to be the same as annex G. I find this confusing and suggest you
use different terms

			Even in the draft the text is not using the new
defined terms correctly. See all the usage of base layer in the text
above section 5.

			Also the text for full base layer is different
from annex G which I find clearer since it mentions the VCL NAL units
that should be used in the base layer and which should not.

			I also noticed that you use base layer only in
the layer definition (did you mean base of full base) so it looks
redundant

			Roni

---

From: "Even, Roni" <[email-masked]>
Date: Fri, 4 Jan 2008 15:25:12 +0200

YK,

Look in 3.1, you use base layer but if you refer to the term in the
draft than it should have been full base layer

Roni

From: [email-masked] [mailto:[email-masked]] 
Sent: Friday, January 04, 2008 2:10 AM
To: Even, Roni; [email-masked]
Subject: RE: [AVT] draft-ietf-avt-rtp-svc-04 base layer term

Hi again Roni,

BR, YK

	Hi,

	Roni

---

From: <[email-masked]>
Date: Fri, 4 Jan 2008 20:48:21 +0200

Roni,
 
We intended not to use "full base layer" in 3.1, and say "A Layer may be
the base Layer or enhance the temporal resolution (i.e. the frame rate),
the spatial resolution, or the quality of the video content, relative to
the quality represented without the Layer." Thus a Layer may be a
temporal enhancement layer containing only AVC NAL units. 
 
However, you are right that we should express in the introduction that
the full base layer is AVC compatible. Will add a sentence for this. 
 
BR, YK

	From: ext Even, Roni [mailto:[email-masked]] 
	Sent: Friday, January 04, 2008 3:25 PM
	To: Wang Ye-Kui (Nokia-OCTO/Tampere); [email-masked]
	Subject: RE: [AVT] draft-ietf-avt-rtp-svc-04 base layer term

	YK,

	Look in 3.1, you use base layer but if you refer to the term in
the draft than it should have been full base layer

	Roni

	Hi again Roni,

than having the same term as in the SVC coding spec but with different

	However, I disagree that in the current draft the defined terms
"base layer" and "full base layer" are not used correctly. Besides these
two definitions themselves, in all other occuring places, they are used
as they are defined. There is one exception of "base layer" in the open
issues - but I think you did not mean that one. 

	BR, YK

		Hi,

		In section 5.1.2 you define the base layer different
from the definition in annex G of H.264. You define full base layer to
be the same as annex G. I find this confusing and suggest you use
different terms

		Even in the draft the text is not using the new defined
terms correctly. See all the usage of base layer in the text above
section 5.

		Also the text for full base layer is different from
annex G which I find clearer since it mentions the VCL NAL units that
should be used in the base layer and which should not.

		Roni