Re: [xrblock] [rtcweb] FW: I-DAction:draft-alvestrand-rtcweb-stats-registry-00.txt

Qin Wu <> Sat, 29 September 2012 03:40 UTC

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From: Qin Wu <>
To: Harald Alvestrand <>,
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Date: Sat, 29 Sep 2012 11:40:26 +0800
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Subject: Re: [xrblock] [rtcweb] FW: I-DAction:draft-alvestrand-rtcweb-stats-registry-00.txt
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----- Original Message ----- 
From: "Harald Alvestrand" <>
To: <>
Sent: Friday, September 28, 2012 7:31 PM
Subject: Re: [rtcweb] [xrblock]FW: I-DAction:draft-alvestrand-rtcweb-stats-registry-00.txt

> On 09/27/2012 01:20 AM, Schwarz, Albrecht (Albrecht) wrote:
>>> I am happy to see my comments being forwarded to if
>> they
>>> are interested and want to more input from XRBLOCK WG. However I am
>> not
>>> sure how much of their work is related to XRBLOCK work? Do they only
>>> look for some basic metrics obtained from SR/RR. But I agree with you
>>> consistency between the metrics used by RTCP XR and RTCWEB is a good
>>> thing.
>> The work on "rtcweb-stats" is related to XRBLOCK in my opinon.
>> At least the "basic metrics from SR/RR" with respect to packet loss are controversial and could be misleading, and should be replaced by correspondent XR performance metric types.
>> The deficiency of some of these basic metrics was one reason to start work on extension reports (XR, and former HR).
> Indeed. The reason I started the document with packet counts and packet 
> loss from SR/RR was that I thought these would be uncontroversial and 
> unambiguous; I'm seeking guidance from XR people on what other metrics 
> are well known enough - and implemented widely enough - that it makes 
> sense to include them.
> (For reference, the WebRTC codebase seems to decode block type 7 and no 
> other block type....)

[Qin]: For jitter, you may refer to both RFC3550 section 6.4.1 for inter-arrival jitter and
draft-ietf-xrblock-rtcp-xr-pdv for "2-point PDV" and "Absolute Packet Delay Variation 2 (MAPDV2) ".
Since jitter is also known as Packet Delay Variation.

For other metrics, I think you may also include round trip delay metric by referring to draft-ietf-rtcp-xr-delay
include discard metric by referring to draft-ietf-rtcp-xr-discard.

For measurement timing for these XR blocks, you should refer to draft-ietf-xrblock-meas-identity.

If you look into end device related metrics, you may look at jitter buffer metric,
concealment seconds metrics, loss concealment metrics developed in XRBLOCK WG, 
these metrics also affect real time appliation quality.
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