Re: [AVT] Comments on draft-ietf-avt-rtp-svc-07.txt

Hi,

I am also confused why the packetization rules talks only about receivers, I would assume that the packetization is done by the sender and the sender should be able to send based on the receiver capabilities. This means that the sender MUST send the base using with single NAL unit if he wants a receiver supporting only this mode to process the stream

Roni

From: mike.nilsson at bt.com [mailto:mike.nilsson at bt.com]
Sent: Tuesday, February 19, 2008 3:33 PM
To: Even, Roni; ye-kui.wang at nokia.com; jonathan at vidyo.com; schierl at hhi.fhg.de
Cc: avt at ietf.org
Subject: RE: Comments on draft-ietf-avt-rtp-svc-07.txt

Roni,

I think we are in agreement here.

The text in the current draft that immediately precedes my proposed changed wording “… use of the single NAL unit packetization mode SHOULD be avoided whenever possible …” states “All receivers MUST support the single NAL unit packetization mode to provide backward compatibility to endpoints supporting only the single NAL unit mode of RFC 3984.”

Concerning the different packetisation modes that a receiver can support, my bullet point in comment 1 was too brief – it is clearly misleading. I think the following are the only two types of SVC receiver that we are allowing:

1) a receiver that supports the non-interleaved packetisation mode AND the single NAL unit mode

2) a receiver that supports the interleaved packetisation mode AND the non-interleaved packetisation mode AND the single NAL unit mode

Unlike RFC3984, a receiver can not support only the single NAL unit mode? (Unless it IS a RFC3984 receiver, capable of receiving H.264/AVC and not SVC).

Best regards

Mike

From: Even, Roni [mailto:roni.even at polycom.co.il]
Sent: 19 February 2008 12:20
To: Nilsson,ME,Mike,CXR4 R; ye-kui.wang at nokia.com; jonathan at vidyo.com; schierl at hhi.fhg.de
Cc: avt at ietf.org
Subject: RE: Comments on draft-ietf-avt-rtp-svc-07.txt

Mike,

About the single NAL unit.

In 1) "this specification supports the use of the interleaved and non-interleaved packetisation modes of RFC3984, but not the single NAL unit mode;"

Single NAL unit is supported in some cases. You have it in 16) about packetization rules. I am OK with your text but if you say whenever possible there should be some text stating that they may be used in the base layer for backward interoperability with systems that support RFC3984.

Roni