draft-ietf-xrblock-rtcp-xr-loss-conceal-01.txt   draft-ietf-xrblock-rtcp-xr-loss-conceal-02.txt 
Network Working Group C. Bi Network Working Group C. Bi
Internet-Draft STTRI Internet-Draft STTRI
Intended status: Standards Track A. Clark Intended status: Standards Track A. Clark
Expires: December 24, 2012 Telchemy Expires: January 3, 2013 Telchemy
G. Hunt G. Hunt
Unaffiliated Unaffiliated
Q. Wu Q. Wu
Huawei Huawei
G. Zorn, Ed. G. Zorn, Ed.
Network Zen Network Zen
June 22, 2012 July 2, 2012
RTCP XR Report Block for Loss Concealment Metric Reporting RTCP XR Report Block for Loss Concealment Metric Reporting
draft-ietf-xrblock-rtcp-xr-loss-conceal-01.txt draft-ietf-xrblock-rtcp-xr-loss-conceal-02.txt
Abstract Abstract
This document defines an RTCP XR Report Block that allows the This document defines an RTCP XR Report Block that allows the
reporting of Loss Concealment metrics primarily for audio reporting of loss concealment metrics primarily for audio
applications of RTP. applications of RTP.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 24, 2012. This Internet-Draft will expire on January 3, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Standards Language . . . . . . . . . . . . . . . . . . . . 3 1.1. Standards Language . . . . . . . . . . . . . . . . . . . . 3
1.2. Loss Concealment Report Block . . . . . . . . . . . . . . . 3 1.2. Loss Concealment Report Block . . . . . . . . . . . . . . . 3
1.3. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3 1.3. RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . 3
1.4. Performance Metrics Framework . . . . . . . . . . . . . . . 4 1.4. Performance Metrics Framework . . . . . . . . . . . . . . . 4
1.5. Applicability . . . . . . . . . . . . . . . . . . . . . . . 4 1.5. Applicability . . . . . . . . . . . . . . . . . . . . . . . 4
2. Loss Concealment Block . . . . . . . . . . . . . . . . . . . . 4 2. Loss Concealment Block . . . . . . . . . . . . . . . . . . . . 4
2.1. Report Block Structure . . . . . . . . . . . . . . . . . . 4 2.1. Report Block Structure . . . . . . . . . . . . . . . . . . 4
2.2. Definition of Fields in Loss Concealment Report Block . . . 4 2.2. Definition of Fields in Loss Concealment Report Block . . . 4
3. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
4.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 8 4.1. New RTCP XR Block Type value . . . . . . . . . . . . . . . 8
4.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . . 8 4.2. New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . . 8
4.3. Contact Information for Registrations . . . . . . . . . . . 8 4.3. Contact Information for Registrations . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 9 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
1.1. Standards Language 1.1. Standards Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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The new block type provides metrics for actions taken by the receiver The new block type provides metrics for actions taken by the receiver
to mitigate the effect of packet loss and packet discard. to mitigate the effect of packet loss and packet discard.
Specifically, the first metric (On-Time Playout Duration) reports the Specifically, the first metric (On-Time Playout Duration) reports the
duration of normal playout of data which the receiver obtained from duration of normal playout of data which the receiver obtained from
the sender's stream. A second metric (Loss Concealment Duration) the sender's stream. A second metric (Loss Concealment Duration)
reports the total time during which the receiver played out media reports the total time during which the receiver played out media
data which was manufactured locally, because the sender's data for data which was manufactured locally, because the sender's data for
these periods was not available due to packet loss or discard. A these periods was not available due to packet loss or discard. A
similar metric (Buffer Adjustment Concealment Duration) reports the similar metric (Buffer Adjustment Concealment Duration) reports the
duration of playout of locally-manufactured data replacing data which duration of playout of locally-manufactured data replacing data
is unavailable due to adaptation of an adaptive de-jitter buffer. unavailable due to adaptation of an adaptive de-jitter buffer.
Further metrics (Playout Interrupt Count and Mean Playout Interrupt Further metrics (Playout Interrupt Count and Mean Playout Interrupt
Size) report the number of times normal playout was interrupted, and Size) report the number of times normal playout was interrupted, and
the mean duration of these interruptions. the mean duration of these interruptions.
Loss Concealment Duration and Buffer Adjustment Concealment Duration Loss Concealment Duration and Buffer Adjustment Concealment Duration
are reported separately because buffer adjustment is typically are reported separately because buffer adjustment is typically
arranged to occur in silence periods so may have very little impact arranged to occur in silence periods so may have very little impact
on user experience, whilst loss concealment may occur at any time. on user experience, whilst loss concealment may occur at any time.
The metric belongs to the class of transport-related terminal metrics The metric belongs to the class of transport-related terminal metrics
defined in Wu, et al. [I-D.ietf-avtcore-monarch]. defined in Wu, et al. [I-D.ietf-avtcore-monarch].
1.3. RTCP and RTCP XR Reports 1.3. RTCP and RTCP XR Reports
The use of RTCP for reporting is defined in Schulzrinne, et The use of RTCP for reporting is defined in Schulzrinne, et
al. [RFC3550]. Friedman, Cacares & Clark [RFC3611] define an al. [RFC3550]. Friedman, Cacares & Clark [RFC3611] define an
extensible structure for reporting using an RTCP Extended Report extensible structure for reporting using an RTCP Extended Report
(XR). This draft defines a new Extended Report block that MUST be (XR). This draft defines a new Extended Report block that MUST be
used as defined in RFC 3550 and RFC 3611. used as specified in RFC 3550 and RFC 3611.
1.4. Performance Metrics Framework 1.4. Performance Metrics Framework
Clark & Claise [RFC6390] provides guidance on the definition and Clark & Claise [RFC6390] provides guidance on the definition and
specification of performance metrics. Wu, et specification of performance metrics. Wu, et
al. [I-D.ietf-avtcore-monarch] provides guidelines for RTCP XR report al. [I-D.ietf-avtcore-monarch] provides guidelines for RTCP XR report
block formats. The report block defined in this document is in block formats. The report block defined in this document is in
accordance with those guidelines. accordance with those guidelines.
1.5. Applicability 1.5. Applicability
This metric is primarily applicable to audio applications of RTP. This metric is primarily applicable to audio applications of RTP.
EDITOR'S NOTE: are there metrics for concealment of transport errors EDITOR'S NOTE: are there metrics for concealment of transport errors
for video? for video?
2. Loss Concealment Block 2. Loss Concealment Block
2.1. Report Block Structure 2.1. Report Block Structure
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 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=NLC | I |plc| rsv. | block length=5 | | BT=<NLC> | I |plc| resv | block length=5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| On-time Playout Duration | | On-time Playout Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loss Concealment Duration | | Loss Concealment Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Buffer Adjustment Concealment Duration | | Buffer Adjustment Concealment Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Playout Interrupt Count | Mean Playout Interrupt Size | | Playout Interrupt Count | Mean Playout Interrupt Size |
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Figure 1: Structure of the Loss Concealment Metrics Block Figure 1: Structure of the Loss Concealment Metrics Block
2.2. Definition of Fields in Loss Concealment Report Block 2.2. Definition of Fields in Loss Concealment Report Block
Block type (BT): 8 bits Block type (BT): 8 bits
A Loss Concealment Metrics Report Block is identified by the A Loss Concealment Metrics Report Block is identified by the
constant <NLC>. constant <NLC>.
[Note to RFC Editor: please replace <NLC> with the IANA provided [Note to RFC Editor: please replace <NLC> with the RTCP XR block
RTCP XR block type for this block.] type allocated by IANA for this block.]
Interval Metric flag (I): 2 bit Interval Metric flag (I): 2 bits
This field is used to indicate whether the Delay metrics are This field is used to indicate whether the delay metrics are
Sampled, Interval or Cumulative metrics, that is, whether the sampled, interval or cumulative metrics, that is, whether the
reported values applies to the most recent measurement interval reported values applies to the most recent measurement interval
duration between successive metrics reports (I=10) (the Interval duration between successive metrics reports (I=10) (the interval
Duration) or to the accumulation period characteristic of duration) or to the accumulation period characteristic of
cumulative measurements (I=11) (the Cumulative Duration) or is a cumulative measurements (I=11) (the cumulative duration) or is a
sampled instantaneous value (I=01) (Sampled Value). sampled instantaneous value (I=01) (sampled value).
Packet Loss Concealment Method (plc): 2 bits Packet Loss Concealment Method (plc): 2 bits
This field is used to identify the packet loss concealment method This field is used to identify the packet loss concealment method
in use at the receiver, according to the following code: in use at the receiver, according to the following scheme:
bits 014-015
0 = silence insertion
1 = simple replay, no attenuation 00 = silence insertion
2 = simple replay, with attenuation 01 = simple replay, no attenuation
3 = enhanced 10 = simple replay, with attenuation
Other values reserved 11 = enhanced
Reserved (resv): 4 bits Reserved (resv): 4 bits
These bits are reserved. They SHOULD be set to zero by senders These bits are reserved. They MUST be set to zero by senders and
and MUST be ignored by receivers. SHOULD be ignored by receivers.
block length: 16 bits block length: 16 bits
The length of this report block in 32-bit words, minus one. For The length of this report block in 32-bit words, minus one. For
the Delay block, the block length is equal to 5. the Loss Concealment block, the block length is equal to 5.
SSRC of source: 32 bits SSRC of source: 32 bits
As defined in Section 4.1 of RFC 3611. As defined in Section 4.1 of RFC 3611.
On-time Playout Duration (ms): 32 bits On-time Playout Duration (ms): 32 bits
'On-time' playout is the uninterrupted, in-sequence playout of 'On-time' playout is the uninterrupted, in-sequence playout of
valid decoded audio information originating from the remote valid decoded audio information originating from the remote
endpoint. This includes comfort noise during periods of remote endpoint. This includes comfort noise during periods of remote
talker silence, if voice activity detection (VAD) is in use, and talker silence if voice activity detection (VAD) is in use, and
locally generated or regenerated tones and announcements. locally generated or regenerated tones and announcements.
An equivalent definition is that on-time playout is playout of any An equivalent definition is that on-time playout is playout of any
signal other than those used for concealment. signal other than those used for concealment.
On-time playout duration MUST include both speech and silence On-time playout duration MUST include both speech and silence
intervals, whether VAD is used or not. This duration is reported intervals, whether VAD is used or not. This duration is reported
in millisecond units. in millisecond units.
If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE
SHOULD be reported to indicate an over-range measurement. If the SHOULD be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFFFF SHOULD be measurement is unavailable, the value 0xFFFFFFFF SHOULD be
reported. reported.
Loss Concealment Duration (ms): 32 bits Loss Concealment Duration (ms): 32 bits
The duration, in milliseconds, of audio playout corresponding to The duration, in milliseconds, of audio playout corresponding to
Loss-type concealment. loss-type concealment.
Loss-type concealment is reactive insertion or deletion of samples Loss-type concealment is reactive insertion or deletion of samples
in the audio playout stream due to effective frame loss at the in the audio playout stream due to effective frame loss at the
audio decoder. "Effective frame loss" is the event in which a audio decoder. "Effective frame loss" is the event in which a
frame of coded audio is simply not present at the audio decoder frame of coded audio is simply not present at the audio decoder
when required. In this case, substitute audio samples are when required. In this case, substitute audio samples are
generally formed, at the decoder or elsewhere, to reduce audible generally formed, at the decoder or elsewhere, to reduce audible
impairment. impairment.
If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE
SHOULD be reported to indicate an over-range measurement. If the SHOULD be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFFFF SHOULD be measurement is unavailable, the value 0xFFFFFFFF SHOULD be
reported. reported.
Buffer Adjustment Concealment Duration (ms): 32 bits Buffer Adjustment Concealment Duration (ms): 32 bits
The duration, in milliseconds, of audio playout corresponding to The duration, in milliseconds, of audio playout corresponding to
Buffer Adjustment-type concealment, if known. buffer adjustment concealment, if known.
If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE If the measured value exceeds 0xFFFFFFFD, the value 0xFFFFFFFE
SHOULD be reported to indicate an over-range measurement. If the SHOULD be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFFFF SHOULD be measurement is unavailable, the value 0xFFFFFFFF SHOULD be
reported. reported.
Buffer Adjustment-type concealment is proactive or controlled Buffer adjustment concealment is proactive or controlled insertion
insertion or deletion of samples in the audio playout stream due or deletion of samples in the audio playout stream due to jitter
to jitter buffer adaptation, re-sizing or re-centering decisions buffer adaptation, re-sizing or re-centering decisions within the
within the endpoint. endpoint.
Because this insertion is controlled, rather than occurring Because this insertion is controlled, rather than occurring
randomly in response to losses, it is typically less audible than randomly in response to losses, it is typically less audible than
loss-type concealment. For example, jitter buffer adaptation loss-type concealment. For example, jitter buffer adaptation
events may be constrained to occur during periods of talker events may be constrained to occur during periods of talker
silence, in which case only silence duration is affected, or silence, in which case only silence duration is affected, or
sophisticated time-stretching methods for insertion/deletion sophisticated time-stretching methods for insertion/deletion
during favorable periods in active speech may be employed. during favorable periods in active speech may be employed.
Concealment events which cannot be classified as Buffer Concealment events which cannot be classified as buffer adjustment
Adjustment- type MUST be classified as Loss-type. MUST be classified as loss concealment.
Playout Interrupt Count: 16 bits Playout Interrupt Count: 16 bits
The number of interruptions to normal playout which occurred The number of interruptions to normal playout which occurred
during the reporting period. during the reporting period.
If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be If the measured value exceeds 0xFFFD, the value 0xFFFE SHOULD be
reported to indicate an over-range measurement. If the reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFF SHOULD be reported. measurement is unavailable, the value 0xFFFF SHOULD be reported.
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The use of the Session Description Protocol (SDP) [RFC4566] for The use of the Session Description Protocol (SDP) [RFC4566] for
signaling the use of XR blocks is described in RFC 3611. XR blocks signaling the use of XR blocks is described in RFC 3611. XR blocks
MAY be used without prior signaling. MAY be used without prior signaling.
This section augments the SDP attribute "rtcp-xr" [RFC3611] by This section augments the SDP attribute "rtcp-xr" [RFC3611] by
providing an additional value of "xr-format" to signal the use of the providing an additional value of "xr-format" to signal the use of the
report block defined in this document. report block defined in this document.
rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF rtcp-xr-attrib = "a=" "rtcp-xr" ":" [xr-format *(SP xr-format)] CRLF
(defined in [RFC3611]) (defined in RFC 3611)
xr-format =/ xr-conceal-block xr-format =/ xr-conceal-block
xr-conceal-block = "loss-conceal" xr-conceal-block = "loss-conceal"
4. IANA Considerations 4. IANA Considerations
New block types for RTCP XR are subject to IANA registration. For New block types for RTCP XR are subject to IANA registration. For
general guidelines on IANA considerations for RTCP XR, refer to RFC general guidelines on IANA considerations for RTCP XR, refer to RFC
3611. 3611.
4.1. New RTCP XR Block Type value 4.1. New RTCP XR Block Type value
This document assigns the block type value NJB in the IANA "RTCP XR This document assigns the block type value <NLC> in the IANA "RTCP XR
Block Type Registry" to the "Loss Concealment Metrics Block". Block Type Registry" to the "Loss Concealment Metrics Block".
[Note to RFC Editor: please replace <NLC> with the RTCP XR block type [Note to RFC Editor: please replace <NLC> with the RTCP XR block type
assigned by IANA for this block.] assigned by IANA for this block.]
4.2. New RTCP XR SDP Parameter 4.2. New RTCP XR SDP Parameter
This document also registers a new parameter "loss-conceal" in the This document also registers a new parameter "loss-conceal" in the
"RTCP XR SDP Parameters Registry". "RTCP XR SDP Parameters Registry".
skipping to change at page 9, line 47 skipping to change at page 9, line 39
(RTCP XR)", RFC 3611, November 2003. (RTCP XR)", RFC 3611, November 2003.
[RFC4566] Handley, M., Jacobson, V., and C. [RFC4566] Handley, M., Jacobson, V., and C.
Perkins, "SDP: Session Description Perkins, "SDP: Session Description
Protocol", RFC 4566, July 2006. Protocol", RFC 4566, July 2006.
7.2. Informative References 7.2. Informative References
[I-D.ietf-avtcore-monarch] Wu, W., Hunt, G., and P. Arden, [I-D.ietf-avtcore-monarch] Wu, W., Hunt, G., and P. Arden,
"Guidelines for Use of the RTP Monitoring "Guidelines for Use of the RTP Monitoring
Framework", draft-ietf-avtcore-monarch-16 Framework", draft-ietf-avtcore-monarch-17
(work in progress), June 2012. (work in progress), June 2012.
[RFC6390] Clark, A. and B. Claise, "Guidelines for [RFC6390] Clark, A. and B. Claise, "Guidelines for
Considering New Performance Metric Considering New Performance Metric
Development", BCP 170, RFC 6390, Development", BCP 170, RFC 6390,
October 2011. October 2011.
Authors' Addresses Authors' Addresses
Claire Bi Claire Bi
Shanghai Research Institure of China Telecom Corporation Limited Shanghai Research Institure of China Telecom Corporation Limited
No.1835,South Pudong Road No.1835, South Pudong Road
Shanghai 200122 Shanghai 200122
China China
EMail: bijy@sttri.com.cn EMail: bijy@sttri.com.cn
Alan Clark Alan Clark
Telchemy Incorporated Telchemy Incorporated
2905 Premiere Parkway, Suite 280 2905 Premiere Parkway, Suite 280
Duluth, GA 30097 Duluth, GA 30097
USA USA
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