draft-ietf-xrblock-rtcp-xr-video-lc-00.txt   draft-ietf-xrblock-rtcp-xr-video-lc-01.txt 
XRBLOCK R. Huang XRBLOCK R. Huang
INTERNET-DRAFT Huawei INTERNET-DRAFT Huawei
Intended Status: Standards Track A. Clark Intended Status: Standards Track A. Clark
Expires: August 29, 2015 Telchemy Expires: January 7, 2016 Telchemy
February 25, 2015 July 6, 2015
RTCP XR Report Block for Loss Concealment Metrics Reporting on RTCP XR Report Block for Loss Concealment Metrics Reporting on
Video Applications Video Applications
draft-ietf-xrblock-rtcp-xr-video-lc-00 draft-ietf-xrblock-rtcp-xr-video-lc-01
Abstract Abstract
This draft defines a new video loss concealment block type to augment This draft defines a new video loss concealment block type to augment
those defined in [RFC3611] and [RFC7294] for use in a range of RTP those defined in [RFC3611] and [RFC7294] for use in a range of RTP
video applications. video applications.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
skipping to change at page 2, line 21 skipping to change at page 2, line 21
Table of Contents Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . . 3 1.1 RTCP and RTCP XR Reports . . . . . . . . . . . . . . . . . . 3
1.2 Performance Metrics Framework . . . . . . . . . . . . . . . 3 1.2 Performance Metrics Framework . . . . . . . . . . . . . . . 3
1.3 Applicability . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Applicability . . . . . . . . . . . . . . . . . . . . . . . 3
2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Video Loss Concealment Methods . . . . . . . . . . . . . . . . 4 3 Video Loss Concealment Methods . . . . . . . . . . . . . . . . 4
4. Video Loss Concealment Report Block . . . . . . . . . . . . . 5 4. Video Loss Concealment Report Block . . . . . . . . . . . . . 5
5 SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 SDP Signaling . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1 SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . . 7 5.1 SDP rtcp-xr-attrib Attribute Extension . . . . . . . . . . . 8
5.2 Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . . 8 5.2 Offer/Answer Usage . . . . . . . . . . . . . . . . . . . . . 8
6 Security Considerations . . . . . . . . . . . . . . . . . . . . 8 6 Security Considerations . . . . . . . . . . . . . . . . . . . . 9
7 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 7 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 9
7.1 New RTCP XR Block Type Value . . . . . . . . . . . . . . . . 8 7.1 New RTCP XR Block Type Value . . . . . . . . . . . . . . . . 9
7.2 New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . . 9 7.2 New RTCP XR SDP Parameter . . . . . . . . . . . . . . . . . 9
7.3 Contact Information for registrations . . . . . . . . . . . 9 7.3 Contact Information for registrations . . . . . . . . . . . 9
8 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 9 8 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 10
9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1 Normative References . . . . . . . . . . . . . . . . . . . 9 9.1 Normative References . . . . . . . . . . . . . . . . . . . 10
9.2 Informative References . . . . . . . . . . . . . . . . . . 10 9.2 Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Metrics Represented Using the Template from RFC 6390 . 10 Appendix A. Metrics Represented Using the Template from RFC 6390 . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
1 Introduction 1 Introduction
Multimedia applications often suffer from packet losses in IP Multimedia applications often suffer from packet losses in IP
networks. In order to get a reasonable degree of quality in case of networks. In order to get a reasonable degree of quality in case of
packet losses, it is necessary to have loss concealment mechanisms at packet losses, it is necessary to have loss concealment mechanisms at
the decoder. Video loss concealment is a range of techniques to mask the decoder. Video loss concealment is a range of techniques to mask
the effects of packet loss in video communications. the effects of packet loss in video communications.
In some applications, reporting the information of receivers applying In some applications, reporting the information of receivers applying
skipping to change at page 4, line 31 skipping to change at page 4, line 31
displayed frame is frozen for the duration of the loss event. displayed frame is frozen for the duration of the loss event.
b) Inter-frame extrapolation b) Inter-frame extrapolation
If an area of the video frame is damaged by loss, the same area from If an area of the video frame is damaged by loss, the same area from
the previous frame(s) can be used to estimate what the missing pixels the previous frame(s) can be used to estimate what the missing pixels
would have been. This can work well in a scene with no motion but can would have been. This can work well in a scene with no motion but can
be very noticeable if there is significant movement from one frame to be very noticeable if there is significant movement from one frame to
another. Simple decoders may simply re-use the pixels that were in another. Simple decoders may simply re-use the pixels that were in
the missing area while more complex decoders may try to use several the missing area while more complex decoders may try to use several
frames to do a more complex extrapolation. frames to do a more complex extrapolation. Another example of a
sophisticated form of inter-frame repair is to estimate the motion of
the damaged region based on the motion of surrounding regions, and
use that to select what part of the previous frame to use for repair.
c) Interpolation c) Interpolation
A decoder may user the undamaged pixels in the video frame to A decoder may user the undamaged pixels in the video frame to
estimate what the missing block of pixels should have. estimate what the missing block of pixels should have.
d) Error Resilient Encoding d) Error Resilient Encoding
The sender may encode the message in a redundant way so that receiver The sender may encode the message in a redundant way so that receiver
can correct errors using the redundant information. The redundant can correct errors using the redundant information. The redundant
data useful for error resiliency performed at the decoder can be data useful for error resiliency performed at the decoder can be
embedded into the compressed image/video bitstream. For example, the embedded into the compressed image/video bitstream. For example, the
encoder may select an important area of an original video frame, encoder may select a crucial area of an original video frame, extract
extract some important characteristics of this area, e.g., motion some important characteristics of this area as the redundant
vector of each macroblock, and imperceptibly embed them into other information, e.g., redundant motion vector of the first macroblock in
parts of the video frame. FEC is also another error resilient method. a slice of this area and redundant motion vector difference of other
macroblocks in this slice of this area, and imperceptibly embed them
into other parts of the video frame sent in a different RTP packet or
in the next frame, e.g., other slices of this area. FEC is also
another error resilient method.
In this document, we differentiate between frame freeze and the other In this document, we differentiate between frame freeze and the other
3 concealment mechanisms described. 3 concealment mechanisms described.
4. Video Loss Concealment Report Block 4. Video Loss Concealment Report Block
This block reports the video loss concealment metrics to complement This block reports the video loss concealment metrics to complement
the audio metrics defined in [i.d-ietf-xrblock-rtcp-xr-loss- the audio metrics defined in [RFC7294]. The report block SHOULD be in
concealment]. This block may be stacked with other RTCP packets to conjunction with the information from the Measurement Information
form compound RTCP packets and share the average reporting interval Block [RFC6776]. Instances of this metrics block refer by SSRC to the
calculated by the RTCP method described in [RFC3550]. It should be separate auxiliary Measurement Information Block [RFC6776]. This
noted that the metrics in this report block are based on measurements metrics block relies on the measurement period in the Measurement
that are typically made at the time that a video frame is decoded and Information Block indicating the span of the report and SHOULD be
rendered for playout. The metrics in this block MUST be measured at a sent in the same compound RTCP packet as the Measurement Information
consistent point. Block. If the measurement period is not received in the same compound
RTCP packet as this metric block, this metric block MUST be
discarded. It should be noted that the metrics in this report block
are based on measurements that are typically made at the time that a
video frame is decoded and rendered for playout. The metrics in this
block MUST be measured at a consistent point.
The video loss concealment report block has the following format: The video loss concealment report block has the following format:
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 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=VLC | I | V | RSV | block length=6 | | BT=VLC | I | V | RSV | block length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Impaired Duration | | Impaired Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Concealed Duration | | Concealed Duration |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MIFP | MCFP | FFSC | MFFD | | Mean Frame Freeze Duration (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MIFP | MCFP | FFSC | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Format for the Video Loss Concealment Report Block Figure 1: Format for the Video Loss Concealment Report Block
Block Type (BT): 8 bits Block Type (BT): 8 bits
A Video Loss Concealment Report Block is identified by the A Video Loss Concealment Report Block is identified by the
constant VLC. constant VLC.
[Note to RFC Editor: Please replace VLC with the IANA provided [Note to RFC Editor: Please replace VLC with the IANA provided
RTCP XR block type for this block.] RTCP XR block type for this block.]
Interval Metric Flag (I): 2 bits Interval Metric Flag (I): 2 bits
This field indicates whether the reported metric is an interval, This field indicates whether the reported metric is an interval,
cumulative, or sampled metric [RFC6792]: cumulative, or sampled metric [RFC6792]:
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Video Loss Concealment Method Type (V): 2 bits Video Loss Concealment Method Type (V): 2 bits
This field is used to identify the video loss concealment method This field is used to identify the video loss concealment method
type used at the receiver. Each bit indicates one method type, as type used at the receiver. Each bit indicates one method type, as
follow: follow:
V=10 - Frame freeze V=10 - Frame freeze
V=11 - Other Loss Concealment Method V=11 - Other Loss Concealment Method
V=01&00 - Reserved V=01&00 - Reserved
If Frame freeze and other loss concealment method are used
together for the media stream, 2 report blocks, one with V=10 for
frame freeze and one with V=11 for other loss concealment method
SHOULD be compounded together to report the whole concealment
information.
block length: 16 bits block length: 16 bits
This field is in accordance with the definition in [RFC3611]. In This field is in accordance with the definition in [RFC3611]. In
this report block, it MUST be set to 6. The block MUST be this report block, it MUST be set to 6 when V=10 and be set to 5
discarded if the block length is set to a different value. when V=11. The block MUST be discarded if the block length is set
to a different value.
SSRC of source: 32 bits SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611]. As defined in Section 4.1 of [RFC3611].
Impaired Duration: 32 bits Impaired Duration: 32 bits
The total time length, expressed in units of RTP timestamp, of The total time length, expressed in units of RTP timestamp, of
video impaired by transmission loss before applying any loss video impaired by transmission loss before applying any loss
concealment methods. concealment methods.
Two values are reserved: A value of 0xFFFFFFFE indicates out of Two values are reserved: A value of 0xFFFFFFFE indicates out of
range (that is, a measured value exceeding 0xFFFFFFFD) and a value range (that is, a measured value exceeding 0xFFFFFFFD) and a value
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Concealed Duration: 32 bits Concealed Duration: 32 bits
The total time length, expressed in units of RTP timestamp, of The total time length, expressed in units of RTP timestamp, of
concealed damaged video pictures on which loss concealment method concealed damaged video pictures on which loss concealment method
corresponding to V is applied. corresponding to V is applied.
Two values are reserved: A value of 0xFFFFFFFE indicates out of Two values are reserved: A value of 0xFFFFFFFE indicates out of
range (that is, a measured value exceeding 0xFFFFFFFD) and a value range (that is, a measured value exceeding 0xFFFFFFFD) and a value
of 0xFFFFFFFF indicates that the measurement is unavailable. of 0xFFFFFFFF indicates that the measurement is unavailable.
Mean Frame Freeze Duration: 32 bits
Mean Frame Freeze Duration is the mean duration, expressed in
units of RTP timestamp, of the frame freeze events. The value of
Mean Frame Freeze Duration shall be calculated by summing the
total duration of all frame freeze events and dividing by the
number of events. This metric is optional. It only exists
whenV=10.
Mean Impaired Frame Proportion (MIFP): 8 bits Mean Impaired Frame Proportion (MIFP): 8 bits
Mean Impaired Frame Proportion is the mean proportion of each Mean Impaired Frame Proportion is the mean proportion of each
video frame impaired by loss before applying any loss concealment video frame impaired by loss before applying any loss concealment
method during the interval, expressed as a fixed point number with method during the interval, expressed as a fixed point number with
the binary point at the left edge of the field. It is equivalent the binary point at the left edge of the field. It is calculated
to taking the integer part after multiplying the loss fraction by by summing the impaired proportion of each video frame and
256. If a video frame is totally lost, a value of 0xFF shall be dividing by the number of frames during this period. The impaired
used for the frame when calculating the mean value. proportion of each video frame is obtained by dividing the number
of missing macroblocks from this video frame by the total
macroblock number of the video frame, which is equivalent to
taking the integer part after multiplying the fraction by 256. If
a video frame is totally lost, a value of 0xFF shall be used for
the frame when calculating the mean value.
Mean Concealed Frame Proportion (MCFP): 8 bits Mean Concealed Frame Proportion (MCFP): 8 bits
Mean Concealed Frame Proportion is the mean proportion of each Mean Concealed Frame Proportion is the mean proportion of each
video frame to which loss concealment (using V) was applied during video frame to which loss concealment (using V) was applied during
the interval, expressed as a fixed point number with the binary the interval, expressed as a fixed point number with the binary
point at the left edge of the field. It is equivalent to taking point at the left edge of the field. It is calculated by summing
the integer part after multiplying the loss fraction by 256. If a the concealed proportion of each video frame and dividing by the
lost video frame is totally concealed, a value of 0xFF and if number of frames during this period. The concealed proportion of
there are no concealed macroblocks, a value of 0, shall be used each video frame is obtained by dividing the number of concealed
for the frame when calculating the mean value. macroblocks from this video frame by the total macroblock number
of the video frame, which is equivalent to taking the integer part
after multiplying the fraction by 256. If a lost video frame is
totally concealed, a value of 0xFF and if there are no concealed
macroblocks, a value of 0, shall be used for the frame when
calculating the mean value.
Fraction of Frames Subject to Concealment (FFSC): 8 bits Fraction of Frames Subject to Concealment (FFSC): 8 bits
Fraction of Frames Subject to Concealment is calculated by Fraction of Frames Subject to Concealment is calculated by
dividing the number of frames to which loss concealment (using V) dividing the number of frames to which loss concealment (using V)
was applied by the total number of frames and expressing this was applied by the total number of frames and expressing this
value as a fixed point number with the binary point at the left value as a fixed point number with the binary point at the left
edge of the field. It is equivalent to taking the integer part edge of the field. It is equivalent to taking the integer part
after multiplying the loss fraction by 256. A value of 0 indicates after multiplying the fraction by 256. A value of 0 indicates that
that there were no concealed frame and a value of 0xFF indicates there were no concealed frame and a value of 0xFF indicates that
that the frames in the entire measurement interval are all the frames in the entire measurement interval are all concealed.
concealed.
Mean Frame Freeze Duration (MFFD): 8 bits Reserved: 8 bits
Mean Frame Freeze Duration is the mean duration of the frame These bits are reserved for future use. They MUST be set to zero
freeze events. The value of MFFD shall be calculated by summing by senders and ignored by receivers (see Section 4.2 of
the total duration of all frame freeze events and dividing by the [RFC6709]).
number of events. A value of 0xFF shall be used to indicate a
value in excess of 12700 milliseconds. A value of 0 MUST be set
when V=11.
5 SDP Signaling 5 SDP Signaling
[RFC3611] defines the use of SDP (Session Description Protocol) for [RFC3611] defines the use of SDP (Session Description Protocol) for
signaling the use of RTCP XR blocks. However XR blocks MAY be used signaling the use of RTCP XR blocks. However XR blocks MAY be used
without prior signaling (see section 5 of [RFC3611]). without prior signaling (see section 5 of [RFC3611]).
5.1 SDP rtcp-xr-attrib Attribute Extension 5.1 SDP rtcp-xr-attrib Attribute Extension
This session augments the SDP attribute "rtcp-xr" defined in Section This session augments the SDP attribute "rtcp-xr" defined in Section
5.1 of [RFC3611] by providing an additional value of "xr-format" to 5.1 of [RFC3611] by providing an additional value of "xr-format" to
signal the use of the report block defined in this document. signal the use of the report block defined in this document.
xr-format =/ xr-vlc-block xr-format =/ xr-vlc-block
xr-vlc-block = "video-loss-concealment" xr-vlc-block = "video-loss-concealment"
5.2 Offer/Answer Usage 5.2 Offer/Answer Usage
When SDP is used in offer-answer context, the SDP Offer/Answer usage When SDP is used in offer-answer context, the SDP Offer/Answer usage
defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters defined in [RFC3611] for unilateral "rtcp-xr" attribute parameters
applies. For detailed usage of Offer/Answer for unilateral applies. For detailed usage of Offer/Answer for unilateral
parameter, refer to section 5.2 of [RFC3611]. parameter, refer to section 5.2 of [RFC3611].
6 Security Considerations 6 Security Considerations
It is believed that this RTCP XR block introduces no new security It is believed that this RTCP XR block introduces no new security
considerations beyond those described in [RFC3611]. This block does considerations beyond those described in [RFC3611]. This block does
not provide per-packet statistics, so the risk to confidentially not provide per-packet statistics, so the risk to confidentially
skipping to change at page 10, line 12 skipping to change at page 10, line 50
Real-time Transport Control Protocol (RTCP)-Based Feedback Real-time Transport Control Protocol (RTCP)-Based Feedback
(RTP/SAVPF)", RFC 5124, February 2008. (RTP/SAVPF)", RFC 5124, February 2008.
[RFC5105] Lendl, O., "ENUM Validation Token Format Definition", [RFC5105] Lendl, O., "ENUM Validation Token Format Definition",
RFC 5105, December 2007. RFC 5105, December 2007.
[RFC4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R. [RFC4588] Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R.
Hakenberg, "RTP Retransmission Payload Format", RFC 4588, Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
July 2006. July 2006.
[RFC6776] Clark, A. and Q. Wu, "Measurement Identity and Information
Reporting Using a Source Description (SDES) Item and an
RTCP Extended Report (XR) Block", RFC6776, October 2012.
[RFC7201] Westerlund, M. and C., Perkins, "Qptions for Securing RTP [RFC7201] Westerlund, M. and C., Perkins, "Qptions for Securing RTP
Sessions", RFC 7201, April 2014. Sessions", RFC 7201, April 2014.
[RFC7202] Perkins, C. and M., Westerlund, "Securing the RTP [RFC7202] Perkins, C. and M., Westerlund, "Securing the RTP
Framework: Why RTP Does Not Mandate a Single Media Framework: Why RTP Does Not Mandate a Single Media
Security Solution", RFC 7202, April 2014. Security Solution", RFC 7202, April 2014.
[RFC7294] Clark, A., Zorn, G., Bi, C. and Q., Wu, "RTCP XR Report [RFC7294] Clark, A., Zorn, G., Bi, C. and Q., Wu, "RTCP XR Report
Block for Concealment Metrics Reporting on Audio Block for Concealment Metrics Reporting on Audio
Applications", April 2014. Applications", April 2014.
skipping to change at page 10, line 34 skipping to change at page 11, line 28
[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New [RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
Performance Metric Development", BCP 170, RFC 6390, Performance Metric Development", BCP 170, RFC 6390,
October 2011. October 2011.
[RFC6792] Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the [RFC6792] Wu, Q., Hunt, G., and P. Arden, "Guidelines for Use of the
RTP Monitoring Framework", RFC 6792, November 2012. RTP Monitoring Framework", RFC 6792, November 2012.
Appendix A. Metrics Represented Using the Template from RFC 6390 Appendix A. Metrics Represented Using the Template from RFC 6390
TBD. a. Video Impaired Duration Metric
* Metric Name: Video Impaired Duration Metric
* Metric Description: The total time length of video impaired by
transmission loss before applying any loss concealment methods.
* Method of Measurement or Calculation: The metric is based on
measurements that are typically made at the time that a video
frame is decoded and rendered for playout.
* Units of Measurement: This metric is expressed in units of RTP
timestamp.
* Measurement Point(s) with Potential Measurement Domain: It is
measured at the receiving end of the RTP stream.
* Measurement Timing: See paragraph 1 of Section 4.
* Use and Applications: The metric is applicable to video
applications of RTP and the video component of Audio/Video
applications in which packet loss concealment mechanisms are
incorporated into the receiving endpoint to mitigate the impact of
network impairments on QoE.
b. Video Concealed Duration Metric
* Metric Name: Video Concealed Duration Metric
* Metric Description: The total time length of concealed damaged
video pictures on which loss concealment method corresponding to V
is applied.
* Method of Measurement or Calculation: The metric is based on
measurements that are typically made at the time that a video
frame is decoded and rendered for playout.
* Units of Measurement: This metric is expressed in units of RTP
timestamp.
* Measurement Point(s) with Potential Measurement Domain: It is
measured at the receiving end of the RTP stream.
* Measurement Timing: See paragraph 2 of Section 4.
* Use and Applications: These metrics are applicable to video
applications of RTP and the video component of Audio/Video
applications in which packet loss concealment mechanisms are
incorporated into the receiving endpoint to mitigate the impact of
network impairments on QoE.
c. Mean Video Frame Freeze Duration Metric
* Metric Name: Mean Video Frame Freeze Duration Metric
* Metric Description: The mean duration of the frame freeze
events.
* Method of Measurement or Calculation: The metric is based on
measurements that are typically made at the time that a video
frame is decoded and rendered for playout. The metric shall be
calculated by summing the total duration of all frame freeze
events and dividing by the number of events.
* Units of Measurement: This metric is expressed in units of RTP
timestamp.
* Measurement Point(s) with Potential Measurement Domain: It is
measured at the receiving end of the RTP stream.
* Measurement Timing: See paragraph 2 of Section 4.
* Use and Applications: These metrics are applicable to video
applications of RTP and the video component of Audio/Video
applications in which packet loss concealment mechanisms are
incorporated into the receiving endpoint to mitigate the impact of
network impairments on QoE.
d. Mean Impaired Video Frame Proportion Metric
* Metric Name: Mean Impaired Video Frame Proportion Metric
* Metric Description: Mean proportion of each video frame impaired
by loss before applying any loss concealment method during the
interval.
* Method of Measurement or Calculation: The metric is based on
measurements that are typically made at the time that a video
frame is decoded and rendered for playout. It is calculated by
summing the impaired proportion of each video frame and dividing
by the number of frames during this period. The impaired
proportion of each video frame is obtained by dividing the number
of lost RTP packets from this video frame by the total packet
number of the video frame, which is equivalent to taking the
integer part after multiplying the loss fraction by 256. If a
video frame is totally lost, a value of 0xFF shall be used for the
frame when calculating the mean value.
* Units of Measurement: This metric is expressed as a fixed point
number with the binary point at the left edge of the field.
* Measurement Point(s) with Potential Measurement Domain: It is
measured at the receiving end of the RTP stream.
* Measurement Timing: See paragraph 2 of Section 4.
* Use and Applications: These metrics are applicable to video
applications of RTP and the video component of Audio/Video
applications in which packet loss concealment mechanisms are
incorporated into the receiving endpoint to mitigate the impact of
network impairments on QoE.
e. Mean Concealed Video Frame Proportion Metric
* Metric Name: Mean Concealed Video Frame Proportion Metric
* Metric Description: Mean proportion of each video frame to which
loss concealment (using V) was applied during the interval.
* Method of Measurement or Calculation: The metric is based on
measurements that are typically made at the time that a video
frame is decoded and rendered for playout. It is calculated by
summing the concealed proportion of each video frame and dividing
by the number of frames during this period. The concealed
proportion of each video frame is obtained by dividing the number
of concealed macroblocks from this video frame by the total
macroblock number of the video frame, which is equivalent to
taking the integer part after multiplying the fraction by 256. If
a lost video frame is totally concealed, a value of 0xFF and if
there are no concealed macroblocks, a value of 0, shall be used
for the frame when calculating the mean value.
* Units of Measurement: This metric is expressed as a fixed point
number with the binary point at the left edge of the field.
* Measurement Point(s) with Potential Measurement Domain: It is
measured at the receiving end of the RTP stream.
* Measurement Timing: See paragraph 2 of Section 4.
* Use and Applications: These metrics are applicable to video
applications of RTP and the video component of Audio/Video
applications in which packet loss concealment mechanisms are
incorporated into the receiving endpoint to mitigate the impact of
network impairments on QoE.
f. Fraction of Video Frames Subject to Concealment Metric
* Metric Name: Fraction of Video Frames Subject to Concealment
Metric
* Metric Description: Proportion of concealed video frames to
which loss concealment (using V) was applied comparing to the
total number of frames during the interval.
* Method of Measurement or Calculation: The metric is based on
measurements that are typically made at the time that a video
frame is decoded and rendered for playout. This metric is
calculated by dividing the number of frames to which loss
concealment (using V) was applied by the total number of frames.
It is equivalent to taking the integer part after multiplying the
fraction by 256. A value of 0 indicates that there were no
concealed frame and a value of 0xFF indicates that the frames in
the entire measurement interval are all concealed.
* Units of Measurement: This metric is expressed as a fixed point
number with the binary point at the left edge of the field.
* Measurement Point(s) with Potential Measurement Domain: It is
measured at the receiving end of the RTP stream.
* Measurement Timing: See paragraph 2 of Section 4.
* Use and Applications: These metrics are applicable to video
applications of RTP and the video component of Audio/Video
applications in which packet loss concealment mechanisms are
incorporated into the receiving endpoint to mitigate the impact of
network impairments on QoE.
Authors' Addresses Authors' Addresses
Rachel Huang Rachel Huang
Huawei Huawei
101 Software Avenue, Yuhua District 101 Software Avenue, Yuhua District
Nanjing 210012 Nanjing 210012
China China
EMail: rachel.huang@huawei.com EMail: rachel.huang@huawei.com
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