K.2 Calculation
26.2473GPPProgressive Download and Dynamic Adaptive Streaming over HTTP (3GP-DASH)Release 17Transparent end-to-end Packet-switched Streaming Service (PSS)TS
The PSS server should support MOS estimation according to ITU-T P.1203 [49] Mode 0. To enable the MOS estimation, the QoE reporting should include the following metrics in either MPD@metrics or OMA DM QoE Management Object ‘metrics’:
– Initial Playout Delay (section 10.2.5)
– Play List (section 10.2.7)
– MPD Information, unless already available by other means (section 10.2.8)
– Device Information (section 10.2.10)
The attribute MPD.Metrics.Range@duration or the OMA DM QoE Management Object ‘duration’ shall be set to a value between 1 and 5 minutes.
The value of MPD.Metrics.Reporting@reportinginterval or OMA DM QoE Management Object ‘Interval’ shall be larger or equal than the value of MPD.Metrics.Range@duration or OMA DM QoE Management Object ‘duration’.
The DASH client reports collected metrics using quality metric reporting protocol defined in clause 10.6.
The mapping between QoE metrics and input to ITU-T P.1203 [49] Mode 0 is provided in table K-1 to K-4 below.
Table K-1 mapping between QoE metrics and input in ITU-T P.1203 mode 0 model for video stream
|
Video Metrics needed for ITU-T P.1203[49] model |
QoE metrics defined in clause 10.2 |
Remark |
||
|
Description |
Value |
Metric |
Description |
|
|
Target Video bit-rate |
Bit-rate in kbps. |
Mpdinfo |
Provides the MPD information for the representation or subrepresentation identified by representationid and subreplevel, if present. Related attributes: @bandwidth, @width, @height, and @codecs. Note: codec attribute includes video codec profile information and video frame rate information |
Target Video bit-rate has been supported by @bandwidth attribute. Video frame-rate and Video codec and profile have been supported by @ codec attribute. Video encoding resolution has been supported by @width and @height attributes. |
|
Video frame-rate |
Frame rate in frames per second. |
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|
Segment duration |
Duration in seconds |
|||
|
Video encoding resolution |
Number of pixels (WxH) in transmitted video |
|||
|
Video codec and profile |
One of: H264-baseline, H264-high, H264-main |
|||
|
Play List |
Provides information on when and how long different representations or subrepresentations have been used during the session. |
Note that the actual timing of the required input for the P.1203 quality model may be influenced by actions such as play/pause. |
||
Table K-2 mapping between QoE metrics and input in ITU-T P.1203 mode 0 model for audio stream
|
Audio Metrics needed for ITU-T P.1203 model |
QoE metrics defined in clause 10.2 |
Remark |
||
|
Description |
Value |
Metric |
Description |
|
|
Target Audio bit-rate |
Bit-rate in kbps. |
Mpdinfo |
Provides the MPD information for the representation or subrepresentation identified by representationid and subreplevel, if present. Related attributes: @bandwidth, and @codecs. Note: codec attribute includes audio codec profile information, audio sampling frequency and Number of audio channels information |
Target Audio bit-rate has been supported by @bandwidth attribute. Audio codec, Audio sampling frequency and Number of audio channels have been supported by @ codecs attribute. |
|
Segment duration |
Duration in seconds |
|||
|
Audio codec |
One of: AAC-LC, AAC-HEv1, AAC-HEv2, AC3 |
|||
|
Audio sampling frequency |
In Hz |
|||
|
Number of audio channels |
2 |
|||
|
Play List |
Provides information on when and how long different representations or subrepresentations have been used during the session. |
Note that the actual timing of the required input for the P.1203 quality model may be influenced by actions such as play/pause. |
||
Table K-3 mapping between QoE metrics and input in ITU-T P.1203 mode 0 model for stalling
|
Metrics needed for ITU-T P.1203 model |
QoE metrics defined in clause 10.2 |
Remark |
||
|
Description |
Value |
Metric |
Description |
|
|
Buffering event start |
The start time of the buffering/stalling event in seconds relative to the start of the original video clip, expressed in media time (not wall clock time) Note: This is 0 for initial buffering. |
Play List |
The start time of a buffering/stalling event is equal to the end time of a trace entry with the stop reason equal to "rebuffering” |
– |
|
Event duration |
The duration of the buffering/stalling event in seconds. |
Play List |
The duration of each buffer event is calculated from the PlayList according to the example described in the Play List metric clause. |
– |
Table K-4 mapping between QoE metrics and input in ITU-T P.1203 mode 0 model for device information
|
Metrics needed for ITU-T P.1203 model |
QoE metrics defined in clause 10.2 |
Remark |
||
|
Description |
Value |
Metric |
Description |
|
|
The resolution of the image displayed to the user |
Number of pixels (WxH) in displayed video |
Device Information |
videoWidth and videoHeight |
. |
|
The device type on which the media is played |
pc or mobile |
Device Information |
screenWidth x pixelWidth, screenHeight x pixelHeight |
P.1203 formally classifies devices up to 10" (diagonal) as mobiles, but to cover most handheld devices (phones and tablets) devices up to 12" could be classified as mobiles |
|
The size of the video shown |
WxH in mm |
Device Information |
videoWidth x pixelWidth, videoHeight x pixelHeight |
|
Annex L (normative):
QoE Measurement Collection Functionalities