One document matched: draft-wu-xrblock-rtcp-xr-quality-monitoring-04.xml
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<rfc category="std" docName="draft-wu-xrblock-rtcp-xr-quality-monitoring-04"
ipr="trust200902">
<front>
<title abbrev="RTCP XR QoE Report Blocks">RTCP XR Blocks for multimedia
quality metric reporting</title>
<author fullname="Qin Wu" initials="Q." surname="Wu">
<organization>Huawei</organization>
<address>
<postal>
<street>101 Software Avenue, Yuhua District</street>
<city>Nanjing</city>
<region>Jiangsu</region>
<code>210012</code>
<country>China</country>
</postal>
<email>sunseawq@huawei.com</email>
</address>
</author>
<author fullname="Glen Zorn" initials="G." surname="Zorn">
<organization>Network Zen</organization>
<address>
<postal>
<street>77/440 Soi Phoomjit, Rama IV Road</street>
<street>Phra Khanong, Khlong Toie</street>
<city>Bangkok</city>
<code>10110</code>
<country>Thailand</country>
</postal>
<phone>+66 (0) 87 502 4274</phone>
<email>gwz@net-zen.net</email>
</address>
</author>
<author fullname="Roland Schott" initials="R." surname="Schott">
<organization>Deutsche Telekom Laboratories</organization>
<address>
<postal>
<street>Deutsche-Telekom-Allee 7</street>
<street></street>
<city>Darmstadt</city>
<code>64295</code>
<country>Germany</country>
</postal>
<email>Roland.Schott@telekom.de</email>
</address>
</author>
<author fullname="Kai Lee" initials="K." surname="Lee">
<organization>China Telecom</organization>
<address>
<postal>
<street>China Telecom Beijing Research Institute</street>
</postal>
<email>leekai@ctbri.com.cn</email>
</address>
</author>
<date year="2011" />
<abstract>
<t>This document defines an RTCP XR Report Block and associated SDP
parameters that allow the reporting of multimedia quality metrics for
use in a range of RTP applications.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>This draft defines a new block type to augment those defined in <xref
target="RFC3611"></xref>, for use in a range of RTP applications.
<vspace blankLines="1" />The new block type provides information on
multimedia quality using one of several standard metrics.<vspace
blankLines="1" />The metrics belong to the class of application level
metrics defined in <xref target="MONARCH"></xref> (work in
progress).</t>
</section>
<section title="Terminology">
<section title="Standards Language">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119">RFC 2119</xref>.</t>
<t>The terminology used is <list>
<t>Numeric formats S X:Y<list>
<t>where S indicates a two's complement signed representation,
X the number of bits prior to the decimal place and Y the
number of bits after the decimal place.</t>
<t>Hence 8:8 represents an unsigned number in the range 0.0 to
255.996 with a granularity of 0.0039. S7:8 would represent the
range -127.996 to +127.996. 0:16 represents a proper binary
fraction with range</t>
<t>0.0 to 1 - 1/65536 = 0.9999847</t>
<t>though note that use of flag values at the top of the
numeric range slightly reduces this upper limit. For example,
if the 16- bit values 0xfffe and 0xffff are used as flags for
"over-range" and "unavailable" conditions, a 0:16 quantity has
range</t>
<t>0.0 to 1 - 3/65536 = 0.9999542</t>
</list></t>
</list></t>
</section>
</section>
<section title="Applicability">
<t>The Multimedia Quality Metrics Report Block can be used in any
real-time AV application.<vspace blankLines="1" />The factors that
affect real-time AV application quality can be split into two
categories. The first category consists of transport- dependent factors
such as packet loss, delay and jitter (which also translates into losses
in the playback buffer). The factors in the second category are
application-specific factors that affect real time application (e.g.,
video) quality and are sensitivity to network errors. These factors can
be but not limited to video codec and loss recovery technique, coding
bit rate, packetization scheme, and content characteristics. <vspace
blankLines="1" /> Compared with application-specific factors, the
transport-dependent factors sometimes are not sufficient to measure real
time data quality, since the ability to analyze the real time data in
the application layer provides quantifiable measurements for subscriber
Quality of Experience (QoE) that may not be captured in the transmission
layers or from the RTP layer down. In a typical scenario, monitoring of
the transmission layers can produce statistics suggesting that quality
is not an issue, such as the fact that network jitter is not excessive.
However, problems may occur in the service layers leading to poor
subscriber QoE. Therefore monitoring using only network-level
measurements may be insufficient when application layer content quality
is required. <vspace blankLines="1" /> In order to provide accurate
measures of real time application quality when transporting real time
contents across a network, the synthentical multimedia quality Metrics
is highly required which can be conveyed in the RTCP XR packets[RFC3611]
and may have the following three benefits: <vspace
blankLines="1" /><list style="symbols">
<t>Tuning the content encoder algorithm to satisfy real time data
quality requirements</t>
<t>Determining which system techniques to use in a given situation
and when to switch from one technique to another as system
parameters change</t>
<t>Verifying the continued correct operation of an existing
system</t>
</list></t>
</section>
<section anchor="SMQM"
title="Synthetical Multimedia Quality Metrics Block">
<t>This block reports the multimedia application performance or quality
beyond the information carried in the standard RTCP packet format.
Information is recorded about multimedia application QoE metric which
provides a measure that is indicative of the user's view of a service.
Multimedia application QoE metric is commonly expressed as a MOS ("Mean
Opinion Score"), MOS is on a scale from 1 to 5, in which 5 represents
excellent and 1 represents unacceptable. MOS scores are usually obtained
using subjective testing or using objective algorithm. However
Subjective testing to estimate the multimedia quality may be not
suitable for measuring the multimedia quality since the results may vary
from test to test. Therefore using objective algorithm to calculate MOS
scores is recommended. ITU-T recommendations define the methodologies
for assessment of the performance of multimedia stream <xref
target="G.107"></xref><xref target="P.564"></xref><xref
target="G.1082"></xref><xref target="P.NAMS"></xref><xref
target="P.NBAMS"></xref> and provides a method to evaluate QoE
estimation algorithms and objective model for video and audio. Hence
this document recommends vendors and implementers to use these
International Telecommunication Union (ITU)-specified methodologies to
measure parameters when possible. <vspace blankLines="1" /></t>
<section title="Metric Block Structure">
<t>The report block contents are dependent upon a series of flag bits
carried in the first part of the header. Not all parameters need to be
reported in each block. Flags indicate which are and which are not
reported. The fields corresponding to unreported parameters MUST be
present, but are set to zero. The receiver MUST ignore any Perceptual
Quality Metrics Block with a non-zero value in any field flagged as
unreported.</t>
<t>The Synthetical Multimedia Quality Metrics Block has the following
format: <figure>
<artwork>
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=TBD |I| MC | Rsd.| block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rsv. | MOS Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</artwork>
</figure></t>
</section>
<section title="Definition of Fields in Multimedia Quality Metrics Block">
<t><list style="hanging">
<t hangText="Block type (BT): 8 bits"><vspace blankLines="1" />The
Synthetical Multimedia Quality Metrics Block is identified by the
constant <SMQM>. <vspace blankLines="1" /></t>
<t hangText="Interval Metric flag (I): 1 bit "><vspace
blankLines="1" /> This field is used to indicate whether the Basic
Loss/Discard metrics are Interval or Cumulative metrics, that is,
whether the reported values applies to the most recent measurement
interval duration between successive metrics reports (I=1) (the
Interval Duration) or to the accumulation period characteristic of
cumulative measurements (I=0) (the Cumulative Duration). <vspace
blankLines="1" /></t>
<t hangText="MoS Type (MT): 4 bits"><vspace blankLines="1" />This
field is used to indicate the MOS type to be reported. The MOS
type is defined as follows: <vspace blankLines="1" /><list>
<t>0000 MOS-LQ - Listening Quality MoS.</t>
<t>0001 MOS-CQ - Conversation Quality MoS.</t>
<t>0010 MOS-V - Video Quality MOS.</t>
<t>0011 MOS-AV - Audio-Video Quality MOS.</t>
<t>0100~1111 - Reserved for future definitions.<vspace
blankLines="1" /></t>
</list>MoS-LQ measures the quality of audio for listening
purposes only while MoS-CQ measures the quality of audio for
conversation purpose only. MoS-V and MoS-AV measures the quality
of video application or Audio-Video application.Both MoS-LQ and
MoS-CQ are commonly used in VoIP applications. MOS-LQ uses either
wideband audio codec or narrowband audio codec, or both and does
not take into account any of bidirectional effects, such as delay
and echo. MOS-CQ uses narrowband codec and takes into account
listening quality in each direction, as well as the bidirectional
effects. If MoS type is MoS-LQ and MoS-CQ, the MoS value can be
calculated based on ITU-T G.107<xref target="G.107"></xref>, ITU-T
P.564 <xref target="P.564"></xref>or ETSI TS 101 329-5 <xref
target="ETSI"></xref>, if the Mos type is MoS-V or MoS-AV, the Mos
value can be calculated based on ITU-T P.NAMS <xref
target="P.NAMS"></xref>or ITU-T P.NBAMS <xref
target="P.NBAMS"></xref>. If new MOS types are defined, they can
be added by an update to this document. If the receiver does not
understand the MOS type defined in this document it should discard
this report.<vspace blankLines="1" /></t>
<t hangText="Rsd.:3 bits "><vspace blankLines="1" /> This field is
reserved for future definition. In the absence of such a
definition, the bits in this field MUST be set to zero and MUST be
ignored by the receiver. <vspace blankLines="1" /></t>
<t hangText="Block Length: 16 bits"><vspace blankLines="1" />The
length of this report block in 32-bit words, minus one. For the
Packet Delay Variation Metrics block, the block length is equal to
2.<vspace blankLines="1" /></t>
<t hangText="SSRC of source: 32 bits"><vspace blankLines="1" /> As
defined in Section 4.1 of <xref target="RFC3611"></xref>. <vspace
blankLines="1" /></t>
<t hangText="Rsd.:16 bits "><vspace blankLines="1" /> This field
is reserved for future definition. In the absence of such a
definition, the bits in this field MUST be set to zero and MUST be
ignored by the receiver. <vspace blankLines="1" /></t>
<t hangText="MOS Value: 16 bits"><vspace blankLines="1" />The
estimated mean opinion score for multimedia application quality is
defined as including the effects of delay,loss, discard,jitter and
other effects that would affect multimedia quality . It is
expressed in numeric format 8:8 with the value in the range 0.0 to
255.996. The valid the measured value ranges from 0.0 to 50.0,
corresponding to MoS x 10 as for MoS. If the measured value is
over ranged, the value 0xFFFE SHOULD be reported to indicate an
over-range measurement. If the measurement is unavailable, the
value 0xFFFF SHOULD be reported. Values other than 0xFFFE,0xFFFF
and the valid range defined above MUST NOT be sent and MUST be
ignored by the receiving system. <vspace blankLines="1" /></t>
</list></t>
</section>
</section>
<section title="SDP Signaling">
<t>One new parameter is defined for the report block defined in this
document to be used with Session Description Protocol (SDP) <xref
target="RFC4566"></xref> using the Augmented Backus-Naur Form (ABNF)
<xref target="RFC5234"></xref>. It has the following syntax within the
"rtcp-xr" attribute <xref target="RFC3611"></xref>: <figure align="left">
<artwork>
rtcp-xr-attrib = "a=rtcp-xr:"
[xr-format *(SP xr-format)] CRLF
xr-format = multimedia-quality-metrics
multimedia-quality-metrics = "multimedia-quality-metrics"
</artwork>
</figure> Refer to Section 5.1 of <xref target="RFC3611">RFC
3611</xref> for a detailed description and the full syntax of the
"rtcp-xr" attribute.</t>
</section>
<section title="IANA Considerations">
<t>New report block types for RTCP XR are subject to IANA registration.
For general guidelines on IANA allocations for RTCP XR, refer to <xref
target="RFC3611">Section 6.2 of</xref>. <vspace blankLines="1" /> This
document assigns one new block type value in the RTCP XR Block Type
Registry: <list>
<t><list hangIndent="12" style="hanging">
<t hangText="Name:">SMQM</t>
<t hangText="Long Name:">Synthetical Multimedia Quality
Metric</t>
<t hangText="Value"><SMQM></t>
<t hangText="Reference:"><xref target="SMQM"></xref> <vspace
blankLines="1" /></t>
</list></t>
</list> This document also registers one new SDP <xref
target="RFC4566"></xref> parameter for the "rtcp-xr" attribute in the
RTCP XR SDP Parameters Registry: <list>
<t><list style="symbols">
<t>“multimedia-quality-metrics”</t>
</list></t>
</list> <vspace blankLines="1" /> The contact information for the
registrations is: <figure align="center">
<artwork>
Qin Wu
sunseawq@huawei.com
101 Software Avenue, Yuhua District
Nanjing, JiangSu 210012 China
</artwork>
</figure></t>
</section>
<section title="Security Considerations">
<t>The new RTCP XR report blocks proposed in this document introduces no
new security considerations beyond those described in <xref
target="RFC3611"></xref>.</t>
</section>
<section title="Acknowledgements">
<t>The authors would like to thank Alan Clark, Bill Ver Steeg, David R
Oran, Ali Begen,Colin Perkins, Roni Even,Youqing Yang, Wenxiao Yu and
Yinliang Hu for their valuable comments and suggestions on this
document.</t>
</section>
</middle>
<back>
<references title="Normative References">
&rfc3611;
&rfc2119;
&rfc4566;
&rfc5234;
</references>
<references title="Informative References">
<reference anchor="G.1082">
<front>
<title>Measurement-based methods for improving the robustness of
IPTV performance</title>
<author>
<organization>ITU-T</organization>
</author>
<date month="April" year="2009" />
</front>
<seriesInfo name="ITU-T Recommendation" value="G.1082" />
</reference>
<reference anchor="P.564">
<front>
<title>Conformance testing for narrowband Voice over IP transmission
quality assessment models</title>
<author>
<organization>ITU-T</organization>
</author>
<date month="July" year="2006" />
</front>
<seriesInfo name="ITU-T Recommendation" value="P.564" />
</reference>
<reference anchor="G.107">
<front>
<title>The E Model, a computational model for use in transmission
planning</title>
<author>
<organization>ITU-T</organization>
</author>
<date month="April" year="2009" />
</front>
<seriesInfo name="ITU-T Recommendation" value="G.107" />
</reference>
<reference anchor="ETSI">
<front>
<title>Quality of Service (QoS) measurement methodologies</title>
<author>
<organization>ETSI</organization>
</author>
<date month="November" year="2000" />
</front>
<seriesInfo name="ETSI" value="TS 101 329-5 V1.1.1" />
</reference>
<reference anchor="P.NAMS">
<front>
<title>Non-intrusive parametric model for the Assessment of
performance of Multimedia Streaming</title>
<author>
<organization>ITU-T</organization>
</author>
<date month="November" year="2009" />
</front>
<seriesInfo name="ITU-T Recommendation" value="P.NAMS" />
</reference>
<reference anchor="P.NBAMS">
<front>
<title>non-intrusive bit-stream model for assessment of performance
of multimedia streaming</title>
<author>
<organization>ITU-T</organization>
</author>
<date month="November" year="2009" />
</front>
<seriesInfo name="ITU-T Recommendation" value="P.NBAMS" />
</reference>
<reference anchor="MONARCH">
<front>
<title>Monitoring Architectures for RTP</title>
<author fullname="Qin Wu" initials="Q." surname="Wu">
<organization>Huawei</organization>
</author>
<date month="April" year="2011" />
</front>
<seriesInfo name="ID" value="draft-ietf-avtcore-monarch-00" />
<format type="TXT" />
</reference>
</references>
<section title="Change Log">
<section title="draft-wu-xrblock-rtcp-xr-quality-monitoring-03">
<t>The following are the major changes compared to previous version
02: <list style="symbols">
<t>Remove the tag field.</t>
<t>Define MOS Value field as 32 bits integer value field.</t>
<t>Clear unused references.</t>
<t>Add text to MOS type field for clarification.</t>
<t>Other Editorial changes.</t>
</list></t>
</section>
<section title="draft-wu-xrblock-rtcp-xr-quality-monitoring-04">
<t>The following are the major changes compared to previous version
03: <list style="symbols">
<t>Add Numeric format definition and express the MoS-Value in
Numeric format.</t>
<t>Change 32bits MoS Value into 16bits MoS Value.</t>
<t>Add some text to MoS Type definition to clarify the algorithm
calculation.</t>
<t>Separate MoS-A into MoS-LQ and MoS-CQ and add some text to
clarify the difference between them.</t>
<t>Add one more reference for MoS-LQ and MoS-CQ value
calculation.</t>
<t>Other Editorial changes.</t>
</list></t>
</section>
</section>
</back>
</rfc>
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