One document matched: draft-wu-avt-rtcp-xr-quality-monitoring-00.txt
Networking Working Group Q.Wu
Internet Draft Huawei
Intended status: Standard Track G.Zorn
Expires: December 2010 Network Zen
June 29, 2010
RTCP XR Report for video Quality Monitoring
draft-wu-avt-rtcp-xr-quality-monitoring-00.txt
Abstract
This document defines an RTCP XR Report Block that allows the
reporting of video quality metrics primarily for video application of
RTP.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with
the provisions of BCP 78 and BCP 79.
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Table of Contents
1. Introduction.................................................2
2. Requirements Notation........................................4
3. Applicability................................................4
4. RTP Flows Synchronization Delay Report Block.................5
5. Audio-Video Synchronization Report Block.....................6
6. Statistics Summary Report Block..............................7
7. TR 101 290 Decodability Metrics Block........................9
8. Video Stream Metrics Report Block...........................13
8.1. Packet Loss and Discard Metrics........................15
8.2. Burst Metrics..........................................17
8.3. Delay Metrics..........................................18
8.4. Configuration Parameter Metrics........................18
8.5. Jitter Buffer Parameters...............................18
9. Perceptual Quality Metrics Block............................19
10. SDP Signaling..............................................22
11. IANA Consideration.........................................23
12. Security Consideration.....................................25
13. References.................................................25
13.1. Normative References..................................25
13.2. Informative References................................26
1. Introduction
Along with the wide deployment of broadband access and development of
new emerging IPTV services (e.g., broadcast video, video on demand),
there is increasing interest in monitoring and managing networks and
applications that deliver real time application over IP, to ensure
all end users obtain acceptable video/audio quality. The main drives
come from operators, since offering the performance monitoring
capability can help diagnose the potential network impairment,
facilitate in root cause analysis and verify compliance of service
level agreements(SLAs) between Internet Service Providers (ISPs) and
content provider.
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The factors that affect the Real time application quality can be
split into two categories. The first category is network dependent
factors consist of Packet losses, delay and jitter (which also
translates into losses in the playback buffer). The factors in the
second category are application specific factors that affect video
quality and is 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.
Comparing with application specific factors, the network dependent
factors sometimes are not sufficient to measure video quality, since
the ability to analyze the video in the application layer provides
quantifiable measurements for subscriber QoE that may not be captured
in the transmission layers or from the RTP layer down. A typical
monitoring scenario 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 video quality is required.
In order to provide accurate measures of video quality for operator
when transporting video across a network, the video quality Metrics
is highly required which can be conveyed in the RTCP XR packets
[RFC3611] has the following three benefits:
O Tuning the video encoder algorithm to satisfy the video quality
requirements
O Determining which system techniques to use in a given situation and
when to switch from one technique to another as system parameters
change
O Verifying the continued correct operation of an existing system.
As described in [RFC3611], seven report block formats are defined for
network management and quality monitoring. However there are no block
types used for conveying video quality metrics. This document focuses
on specifying new report block types used to convey video specific
quality metrics.
The report block types defined in this document fall into two
categories. The first category consists of synchronization
information on received RTP packets. The report in the second
category convey metrics relating to packet receipts defined in
[RFC3611], that are summary in nature but that are more detailed, or
of a different type, than that conveyed in existing RTCP packets.
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All told, six report block formats are defined by this document. Of
these, two are synchronization information block type
- RTP Flows Synchronization Delay Report Block
- Audio-Video Synchronization Report Block
The other four are the summary metrics block type
- Statistics Summary Report Block
- TR 101 290 [TR101 290] Decodability Metrics Block
- Video Stream Metrics Report Block
- Perceptual Quality Metrics Block
2. Requirements Notation
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 [RFC2119].
3. Applicability
All the report blocks defined in this document could be used by
dedicated network monitoring applications. As specified in [RFC3611],
for such an application, it might be appropriate to allow more than
5% of RTP data bandwidth to be used for RTCP packets, thus allowing
proportionately larger and more detailed report blocks.
Audio-Video Synchronization Report Block has been defined for video
conferencing applications. Any such applications can use this report
block to monitor A/V component synchronization to ensure satisfactory
QOE. The tighter tolerances than typically has been recommended for
such applications.
RTP Flows Synchronization Delay Report Block has been defined
primarily for layered or multi-description video coding application.
In such applications when joining a layered video session, a receiver
may not synchronize playout across the multimedia session until RTCP
SR packets have been received on all of the component RTP sessions.
This report block can be used to ensure synchronization between
different Media layers for the same multimedia session.
Video Stream Metrics Report Block and Statistics Summary Report Block
can be applied to any real time video application, while TR 101 290
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Decodability Metrics Report Block and Perceptual Quality Metrics
Report Block can be used any real time visual-audio application.
4. RTP Flows Synchronization Delay Report Block
This block reports Synchronization Delay between RTP sessions of the
same video stream sent using MST [SVC] beyond the information carried
in the standard RTCP packet format. Information is recorded about
Session Bandwidth and Synchronization Delay.
The RTP Flows Synchronization Delay Report Block has the following
format:
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 | Reserved | Block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Sender |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Initial Synchronization Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Block type (BT): 8 bits
A The Statistics Summary Report Block is identified by the
constant TBD.
Reserved: 8 bits
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.
Block length: 16 bits
The constant 3, in accordance with the definition of this field
in Section 3 of [RFC3611].
SSRC of Sender: 32 bits
The SSRC of the RTP data packet source being reported upon by
this report block. (section 4.1 of RFC 3611).
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Session Bandwidth: 32 bits
This field indicates the maximum bandwidth allocated to each RTP
Session. The value in this field represents the bandwidth
allocation per RTP Session in kilobits per second, with values
in the range 0 <= BW < 65536.
Initial Synchronization Delay: 32 bits
The average delay, expressed in units of 1/65536 seconds,
between the RTCP packets received on all of the components RTP
sessions and the beginning of session. [I.D-ietf-avt-rapid-rtp-
sync-10]. The value is calculated as follows:
Initial Synchronization Delay = Max (the time interval between
Receiving the first RTP packet with Synchronization Metadata and
the start of a session, the time interval between receiving the
first RTCP packet in the RTP session with the longest RTCP
reporting interval and the start of a session).
5. Audio-Video Synchronization Report Block
This block reports the audio-video synchronization requirements
between audio and video components beyond the information carried in
the standard RTCP packet format. Information is recorded about
tolerant audio lead video time and tolerant audio lag video time.
The Audio-Video Synchronization Report Block has the following format:
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 |L| Reserved | Block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Audio Lead Video | Audio Lag Video |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Block type (BT): 8 bits
A The Statistics Summary Report Block is identified by the
constant TBD.
Audio Lead/Lag Video flag(L): 1 bit
Bit set to 1 if Audio Lead Video field contains a report, 0 if
Audio Lag Video field contains a report.
Reserved.: 7 bits
This field is reserved for future definition. In the absence of
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such a definition, the bits in this field MUST be set to zero
and MUST be ignored by the receiver.
Block length: 16 bits
The constant 2, in accordance with the definition of this field
in Section 3 of [RFC3611].
SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611].
Audio Lead Video time: 16 bits
This field indicates the tolerant audio lead video time in
milliseconds [WT-126]. This value is calculated based on the
interarrival time between previous video RTP packet and the next
first audio RTP packet and timestamps of both previous video RTP
packet and the next first audio packet.
Audio Lag Video: 16 bits
This field indicates the tolerant audio lag video time in
milliseconds [WT-126]. This value is calculated based on the
interarrival time between previous video RTP packet and the next
first audio RTP packet and timestamps of both previous video RTP
packet and the next first audio packet.
6. Video Statistics Summary Report Block
This block reports statistics beyond the information carried in the
Statistics Summary Report Block RTCP packet specified in the section
4.6 of [RFC3611]. Information is recorded about lost frame packets,
duplicated frame packets, lost layered component packets, duplicated
layered component packets. Such information can be useful for network
management and video quality monitoring.
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 parameters are
reported and which are not. The fields corresponding to unreported
parameters MUST be present, but are set to zero. The receiver MUST
ignore any Decodaility metrics Block with a non-zero value in any
field flagged as unreported.
The Statistics Summary Report Block has the following format:
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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 |L|D|FT | LT |P| block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| begin_seq | end_seq |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lost_frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| dup frames |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lost_layered component packets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| dup layered component_packets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| lost_partial frame packets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| dup partial frame_packets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Block type (BT): 8 bits
The Statistics Summary Report Block is identified by the
constant TBD.
loss report flag (L): 1 bit
Bit set to 1 if the lost_frame packets field or
lost_layered_component field or lost partial frame packets field
contains a report, 0 otherwise.
duplicate report flag (D): 1 bit
Bit set to 1 if the dup_frame packets field or
dup_layered_component packets field or dup partial frame packets
contains a report, 0 otherwise.
Frame type flag (FT): 2 bits
This field is used to indicate the frame type to be reported.
Bits set to 1 if the lost_frames field or dup_frames field
contain a I_frame report, 2 if the lost_frams field and
dup_frames field contain a P frame report, 3 if the lost_frames
field and dup_frames field contain a B frame report, 0 otherwise.
Layer Type flag (LT): 3 bits
This field is used to indicate the Layer Type of layered video
to be reported. LT is set to 1 if the loss_component_packet
field and dup_component packet contain the base layer packet in
SVC [SVC], 2 if the loss_component packet field and
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dup_component packet contain enhancement layer 1 packet in SVC,
3 if the loss_component packet field and dup_component packet
contain the enhancement layer 2 packet, 0 otherwise.
P: 1 bit
Bit set to 1 if the lost_partial frame packets field or
dup_partial_frame packets field contains a report, 0 otherwise.
Block length: 16 bits
The constant 8, in accordance with the definition of this field
in Section 3 of [RFC3611].
SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611].
begin_seq: 16 bits
As defined in Section 4.1 of [RFC3611].
end_seq: 16 bits
As defined in Section 4.1 of [RFC3611].
lost_frames: 32 bits
Number of lost_frames in the above sequence number interval.
dup_frames: 32 bits
Number of dup_frames in the above sequence number interval.
lost_layered component packets: 32 bits
Number of lost_component packets in the above sequence number
interval.
dup_layered component packets: 32 bits
Number of dup_component packets in the above sequence number
interval.
lost_partial frame packets: 32 bits
Number of lost_partial frame packets in the above sequence
number interval.
dup_partial frame packets: 32 bits
Number of dup_partial frame packets in the above sequence number
interval.
7. TR 101 290 Decodability Metrics Block
This block reports Decodability metrics statistics beyond the
information carried in the standard RTCP packet format. Information
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is recorded about the number of Transport Stream Synchronization
Losses, Sync byte errors, Continuity count errors, Transport errors,
PCR errors, PCR repetition errors, PCR repetition errors, PCR
discontinuity indicator errors, PTS errors. Such information can be
useful for network management and video quality monitoring.
Note that this is only applicable to MPEG-2 Transport stream and not
to any other video codec.
The metrics 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
Decodaility metrics Block with a non-zero value in any field flagged
as unreported.
The Decodability metrics Block has the following format:
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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 |L|B|C|T|P|S|rvd| block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| begin_seq | end_seq |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Number of packets | Number of TS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transport Stream Synchronization Losses |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sync byte errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Continuity count errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transport errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCR errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCR repetition errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PCR discontinuity indicator errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PTS errors |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
block type (BT): 8 bits
A TR101.290 decodability metrics Block is identified by the
constant TBD.
Transport Stream Synchronization Loss flag (L): 1 bit
Bit set to 1 if the Transport Stream Synchronization Loss field
contains a report, 0 otherwise.
Sync byte error flag (B):1 bit
Bit set to 1 if the Continuity count error field contains a
report, 0 otherwise.
Continuity count error flag (C):1 bit
Bit set to 1 if the Sync byte error field contains a report, 0
otherwise.
Transport error flag (T):1 bit
Bit set to 1 if the Transport error field contains a report, 0
otherwise.
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PCR related error flag (P):1 bit
Bit set to 1 if the PCR error field, PCR repetition error field
and PCR discontinuity indicator error field contains a report, 0
otherwise.
PTS error flag (S):1 bit
Bit set to 1 if the PTS error field contains a report, 0
otherwise.
rvd: 2 bits
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.
block length: 16 bits
The constant 10, in accordance with the definition of this field
in Section 3 of [RFC3611].
SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611].
begin_seq: 16 bits
As defined in Section 4.1 of [RFC3611].
end_seq: 16 bits
As defined in Section 4.1 of [RFC3611].
Number of Packets
Number of RTP packets in the above sequence number interval.
Number of TSs
Number of TSs in the above sequence number interval.
Transport Stream Synchronization Losses: 32 bits
Number of Transport Stream Synchronization Losses in the above
sequence number interval.
Sync byte errors: 32 bits
Number of Transport sync byte errors in the above sequence
number interval.
Continuity count error: 32 bits
Number of Transport Continuity count errors in the above
sequence number interval.
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Transport errors: 32 bits
Number of Transport errors in the above sequence number interval.
PCR errors: 32 bits
Number of PCR errors in the above sequence number interval.
PCR repetition errors: 32 bits
Number of Transport PCR repetition errors in the above sequence
number interval.
PCR discontinuity indicator errors: 32 bits
Number of PCR discontinuity indicator errors in the above
sequence number interval.
PTS errors: 32 bits
Number of PTS errors in the above sequence number interval.
8. Video Stream Metrics Report Block
The video Stream Metrics Report Block provides metrics for monitoring
the quality of video stream. This metrics includes Loss and discard
metrics, Burst metrics, Delay metrics for I-Frame packets, B-Frame
packets and P-Frame packets, Configuration parameter metrics. The
block reports separately on packets lost on the IP channel, and those
that have been received but then discarded by the receiving jitter
buffer. It also reports on the combined effect of losses and discards,
as both have equal effect on video quality.
In order to properly assess the quality of a video stream, it is
desirable to consider the degree of burstiness of packet loss
[RFC3357]. Following One-way Loss Pattern Sample Metrics specified in
[RFC3357], a measure of the spacing between consecutive network
packet loss or error events, is a "loss distance". The loss distance
metric captures the spacing between the loss periods. The duration of
a loss or error event (e.g. and how many packets are lost in that
duration) is a "loss period", the loss period metric captures the
frequency and length (burstiness) of loss once it starts. Delay
reports include the transit delay between RTP end points and the end
system processing delays, both of which contribute to the user
perceived delay.
Implementations MUST provide values for all the fields defined here.
For certain metrics, if the value is undefined or unknown, then the
specified default or unknown field value MUST be provided.
The block is encoded as six 32-bit words:
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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 |FT | reserved | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loss rate | Discard rate | Loss Period |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loss Distance | Max Loss Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Round trip delay | End system delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Gmin | RX config | JB nominal |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| JB maximum | JB abs max |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
block type (BT): 8 bits
A Video Stream Metrics Report Block is identified by the
constant TBD.
Frame type flag (FT): 2 bits
This field is used to indicate the frame type to be reported.
Bits set to 1 if the Loss rate field and discard rate field
contain a I_frame report, 2 if the Loss rate field and discard
rate field contain a P frame report, 3 if the Loss rate field
and discard rate field contain a B frame report, 0 otherwise.
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reserved: 6 bits
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.
block length: 16 bits
The constant 8, in accordance with the definition of this field
in Section 3.
SSRC of source: 32 bits
The SSRC of the RTP data packet source being reported upon by
this report block.
The remaining fields are described in the following four sections:
Packet Loss and Discard Metrics, Delay Metrics, Configuration Metrics,
and Jitter Buffer Parameters.
8.1. Packet Loss and Discard Metrics
It is very useful to distinguish between packets lost by the network
and those discarded due to jitter. Both have equal effect on the
quality of the video stream, however, having separate counts helps
identify the source of quality degradation. These fields MUST be
populated, and MUST be set to zero if no packets have been received.
Loss rate for I-Frame packets: 8 bits
The fraction of RTP data packets from the source lost since
the beginning of reception, expressed as a fixed point
number with the binary point at the left edge of the field.
This value is calculated by dividing the total number of I
frame packets lost (after the effects of applying any error
protection such as FEC) by the total number of packets
expected, multiplying the result of the division by 256,
limiting the maximum value to 255 (to avoid overflow), and
taking the integer part. The numbers of duplicated packets
and discarded packets do not enter into this calculation.
Since receivers cannot be required to maintain unlimited
buffers, a receiver MAY categorize late-arriving packets as
lost. The degree of lateness that triggers a loss SHOULD
be significantly greater than that which triggers a discard.
Discard rate for I-Frame packets: 8 bits
The fraction of RTP data packets from the source that have
been discarded since the beginning of reception, due to
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late or early arrival, under-run or overflow at the
receiving jitter buffer. This value is expressed as a
fixed point number with the binary point at the left edge
of the field. It is calculated by dividing the total
number of I-Frame packets discarded(excluding duplicate
packet discards) by the total number of packets expected,
multiplying the result of the division by 256, limiting the
maximum value to 255 (to avoid overflow), and taking the
integer part.
Loss rate for P-Frame packets: 8 bits
The loss rate for P-Frame packets is similar to the loss
rate for I-Frame packets. The value is calculated by
dividing the total number of P frame packets lost (after
the effects of applying any error protection such as FEC)
by the total number of packets expected, multiplying the
result of the division by 256
Discard rate for P-Frame packets: 8 bits
The discard rate for P-Frame packets is similar to the
discard rate for I-Frame packets. The value is calculated
by dividing the total number of P-Frame packet
discarded(excluding duplicate packet discards) by the total
number of packets expected, multiplying the result of the
division by 256.
Loss rate for B-Frame packets: 8 bits
The loss rate for B-Frame packets is similar to the loss
rate for I-Frame packets. The value is calculated by
dividing the total number of B frame packets lost (after
the effects of applying any error protection such as FEC)
by the total number of packets expected, multiplying the
result of the division by 256
Discard rate for B-Frame packets: 8 bits
The discard rate for B-Frame packets is similar to the
discard rate for P-Frame packets. The value is calculated
by dividing the total number of B-Frame packet
discarded(excluding duplicate packet discards) by the total
number of packets expected, multiplying the result of the
division by 256.
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8.2. Burst Metrics
Loss Distance: 16 bits
The mean duration, expressed in milliseconds, of the loss
intervals that have occurred since the beginning of
reception [WT-126]. The duration of each loss distance is
calculated based upon the frames that mark the beginning
and end of that period. It is equal to the timestamp of
the end frame, plus the duration of the end frame, minus
the timestamp of the beginning frame. If the actual values
are not available, estimated values MUST be used. If there
have been no burst periods, the burst duration value MUST
be zero.
Loss Period: 16 bits
The mean duration, expressed in milliseconds, of the burst
loss periods that have occurred since the beginning of
reception [WT-126]. The duration of each period is
calculated based upon the frame that marks the end of the
prior burst loss and the frame that marks the beginning of
the subsequent burst loss. It is equal to the timestamp of
the subsequent burst frame, minus the timestamp of the
prior burst packet, plus the duration of the prior burst
packet. If the actual values are not available, estimated
values MUST be used. In the case of a gap that occurs at
the beginning of reception, the sum of the timestamp of the
prior burst packet and the duration of the prior burst
packet are replaced by the reception start time. In the
case of a gap that occurs at the end of reception, the
timestamp of the subsequent burst packet is replaced by the
reception end time. If there have been no gap periods, the
gap duration value MUST be zero.
Max Loss Duration of a single error: 16 bits
The maximum loss duration, expressed in milliseconds, of the
loss periods that have occurred since the beginning of
reception. The recommended max loss duration is specified
as less than 16 ms in [WT-126], which provides a balance
between interleaver depth protection from impulse noise
induced xDSL errors, delay added to other applications and
video service QoE requirements to reduce visible
impairments.
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8.3. Delay Metrics
Similar to the delay metrics for audio stream defined in the section
4.7.3 of [RFC3611], the delay metrics for video stream fall into two
category: end-system delay due to RTP payload multiplexing and round
trip delay due to multiplexing RTP frames within a UDP frame.
Round trip delay: 16 bits
As defined in Section 4.7.3 of [RFC3611].
End system delay: 16 bits
As defined in Section 4.7.3 of [RFC3611].
8.4. Configuration Parameter Metrics
Similar to the configuration metrics defined in the section 4.7.6 of
[RFC3611], the configuration metrics for video stream include
Gmin,receiver configuration byte,packet loss concealment,jitter
buffer adaptive,jitter buffer rate.
Gmin: 8 bits
As defined in Section 4.7.6 of [RFC3611].
Receiver configuration byte (RX config): 8 bits
As defined in Section 4.7.6 of [RFC3611].
Packet loss concealment (PLC): 2 bits
As defined in Section 4.7.6 of [RFC3611].
Jitter buffer adaptive (JBA): 2 bits
As defined in Section 4.7.6 of [RFC3611].
Jitter buffer rate (JB rate): 4 bits
As defined in Section 4.7.6 of [RFC3611].
8.5. Jitter Buffer Parameters
Similar to the Jitter Buffer Parameters defined in the section 4.7.7
of [RFC3611], the Jitter Buffer Parameters for video stream include
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jitter buffer nominal delay, jitter buffer maximum delay, jitter
buffer absolute maximum delay.
Jitter buffer nominal delay (JB nominal): 16 bits
As defined in Section 4.7.7 of [RFC3611].
Jitter buffer maximum delay (JB maximum): 16 bits
As defined in Section 4.7.7 of [RFC3611].
Jitter buffer absolute maximum delay (JB abs max): 16 bits
As defined in Section 4.7.7 of [RFC3611].
9. Perceptual Quality Metrics Block
This block reports the perceptual Quality Metrics beyond the
information carried in the standard RTCP packet format. Information
is recorded about Video MOS, Audio Video MOS, Video Service
Transmission Quality, Video Service Audio Quality, Video Service
Multimedia Quality, Video Service Picture Quality.
The metrics 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
Decodability metrics Block with a non-zero value in any field flagged
as unreported.
The Perceptual Quality Metrics Block has the following format:
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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|S|T|A|M|P|Rsd| block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MOS-V | MOS-AV |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VSTQ | VSAQ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VSMQ | VSPQ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loss Period VSPQ | Loss Distance VSPQ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Block type (BT): 8 bits
A The Statistics Summary Report Block is identified by the
constant TBD.
Interval Metric flag (I): 1 bit
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).
MOS-V flag (S): 1 bit
Bit set to 1 if the MOS-V field and MOS-AV field contains a
report, 0 otherwise.
Video Service Transmission Quality flag (T): 1 bit
Bit set to 1 if the Video Service Transmission Quality field
contains a report, 0 otherwise.
Video Service Audio Quality flag (A): 1 bit
Bit set to 1 if the Video Service Transmission Quality field
contains a report, 0 otherwise.
Video Service Multimedia Quality flag (M): 1 bit
Bit set to 1 if the Video Service Multimedia Quality field
contains a report, 0 otherwise.
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Video Service Picture Quality flag (P): 1 bit
Bit set to 1 if the Video Service Picture Quality field, Loss
Period VSPQ, Loss Distance VSPQ contains a report, 0 otherwise.
Rsd.: 2 bits
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.
SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611].
MOS-V: 16 bits
The estimated mean opinion score for video quality (MOS-V) is a
video quality metric on a scale from 1 to 5, in which 5
represents excellent and 1 represents unacceptable. This
metric is defined as not including the effects of audio
impairments and can be compared to MOS scores obtained from
video quality tests. It is expressed as an integer in the
range 10 to 50, corresponding to MOS x 10. For example, a
value of 35 would correspond to an estimated MOS score of 3.5.
A value of 127 indicates that this parameter is unavailable.
Values other than 127 and the valid range defined above MUST
not be sent and MUST be ignored by the receiving system.
MOS-AV: 16 bits
The estimated mean opinion score for Audio-Video quality (MOS-
AV) is defined as including the effects of delay and other
effects that would affect Audio-Video quality. It is expressed
as an integer in the range 10 to 50, corresponding to MOS x 10,
as for MOS-AV.
A value of 127 indicates that this parameter is unavailable.
Values other than 127 and the valid range defined above MUST
not be sent and MUST be ignored by the receiving system.
VSTQ: 16 bits
Video Service Transmission Quality (TBC)
VSAQ: 16 bits
Video Service Audio Quality (TBC)
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VSMQ: 16 bits
Video Service Multimedia Quality (TBC)
VSPQ: 16 bits
Video Service Picture Quality (TBC)
Loss Period VSPQ: 16 bits
Video Service Picture Quality during Loss Period (TBC)
Loss Distance VSPQ: 16 bits
Video Service Picture Quality during Loss Distance (TBC)
10. SDP Signaling
Six new parameters are defined for the six report block defined in
this document to be used with Session Description Protocol (SDP)
[RFC4566] using the Augmented Backus-Naur Form (ABNF) [RFC5234]. It
has the following syntax within the "rtcp-xr" attribute [RFC3611]:
rtcp-xr-attrib = "a=rtcp-xr:" [xr-format *(SP xr-format)] CRLF
xr-format = RTP-flows-syn
/audio-video-syn
/percept-quality-metrics
/ video-stream-metric
/ video-stat-summary
/ decodability-metric
RTP-flows-syn =" RTP-flows-syn" ["=" max-size]
audio-video-syn" audio-video-syn" ["=" max-size]
percept-quality-metrics ="percept-quality-metrics" ["=" max-size]
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video-stream-metric ="video-stream-metric" ["=" max-size]
video-stat-summary ="video-stat-summary" ["=" stat-flag *("," stat-flag)]
stat-flag = "I Frame loss and duplication"
/ "P Frame loss and duplication"
/ "B Frame loss and duplication"
decodability-metric ="decodability-metric" ["=" stat-flag *("," stat-
flag)]
stat-flag = " Interval Metric"
/ "MOS-V and MOS-AV"
/" VSTQ"
/"VSAQ"
/"VSMQ"
/"VSPQ"
max-size = 1*DIGIT ; maximum block size in octets
Figure x
Refer to Section 5.1 of [RFC3611] for a detailed description and
the full syntax of the "rtcp-xr" attribute.
11. IANA Consideration
New block types for RTCP XR are subject to IANA registration. For
general guidelines on IANA considerations for RTCP XR, refer to
[RFC3611].
This document assigns six block type values in the RTCP XR Block Type
Registry with the following registrations format:
Name: RFSD
Long Name: RTP Flows Synchronization Delay
Value: TBD
Reference: This document.
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Name: AVS
Long Name: Audio-Video Synchronization
Value: TBD
Reference: This document.
Name: VSS
Long Name: Video Statistics Summary
Value: TBD
Reference: This document.
Name: TDM
Long Name: TR 101 290 Decodability Metrics
Value: TBD
Reference: This document.
Name: VSM
Long Name: Video Stream Metrics
Value: TBD
Reference: This document.
Name: PQM
Long Name: Perceptual Quality Metric
Value: TBD
Reference: This document.
This document also registers the six SDP [RFC4566] parameters for the
"rtcp-xr" attribute in the RTCP XR SDP Parameters Registry,i.e.,
" RTP-flows-syn "
"audio-video-syn"
"percept-quality-metrics"
"video-stream-metric"
"video-stat-summary"
"decodability-metric"
The contact information for the registrations is:
Qin Wu
sunseawq@huawei.com
101 Software Avenue, Yuhua District
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Nanjing, JiangSu 210012 China
12. Security Consideration
TBD.
13. Acknowledgement
The authors would like to thank Youqing Yang, Wenxiao Yu,Yinliang Hu
for their valuable comments and suggestions on this document.
14. References
14.1. Normative References
[RFC2250] Hoffman,D., Fernando,G., Goyal,V., M.Civanlar," RTP
Payload Format for MPEG1/MPEG2 Video",RFC2250,January,1998
[RFC3611] Friedman,T. ,Caceres,R. ,A. Clark," RTP Control Protocol
Extended Reports (RTCP XR)",RFC3611,November,2003
[RFC3357] Koodli,R.,R.,Ranvikanth,"One-way Loss Pattern Sample
Metrics",RFC3357,August,2002
[I.D.ietf-avt-rapid-rtp-sync]
Perkins, C., T. Schierl," Rapid Synchronisation of RTP
Flows", draft-ietf-avt-rapid-rtp-sync (work in
progress),May,2010
[RFC5760] Ott, J. and J. Chesterfield, "RTCP Extensions for Single-
Source Multicast Sessions with Unicast Feedback", RFC5760,
November 2009.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
[SVC] Wenger, S., Wang, Y., Schierl, T., and A. Eleftheriadis,
"RTP Payload Format for SVC Video", draft-ietf-avt-rtp-
svc-21 (work in progress), April 2010.
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14.2. Informative References
[ISO138184]ISO/IEC 13818-4 "Information Technology - Generic coding
of moving pictures and association audio information -
Part4: Conformance Testing"
[WT-126] DSL Forum Technical Report TR-126 "Trip-Play Services
Qualities of Experience (QoE) Requirements",December,2006
[TR101 290] Digital Video Broadcast(DVB);Measurement guideline for
DVB Systems
[J.144]ITU-T Recommendation J.144 "Objective perceptual video
quality measurement techniques for digital cable
television in the presence of a full reference"
[MONARCH] Hunt, G., "Monitoring Architectures for RTP", ID draft-
hunt-avt-monarch-01, August 2008.
[PMOLFRAME]
Clark, A., "Framework for Performance Metric Development",
ID draft-ietf-pmol-metrics-framework-02, March 2009.
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Authors' Addresses
Qin Wu
Huawei Technologies Co.,Ltd.
101 Software Avenue, Yuhua District
Nanjing,JiangSu,210012
China
Email: sunseawq@huawei.com
Glen Zorn
Network Zen
1463 East Republican Street
#358
Seattle, WA 98112
USA
Email: gwz@net-zen.net
Wu Expires December 29, 2010 [Page 27]
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