2.4.1.1 microsoft_latency_management_capability

The microsoft_latency_management_capability parameter specifies whether the Wi-Fi Display Sink is capable of dynamically changing the display latency of the video bit stream. When sent by the Wi-Fi Display Sink, the parameter specifies the desired latency mode.

This parameter is included by the Wi-Fi Display Source in the M3 request to specify support for latency management, by the Wi-Fi Display Sink in the M3 response to specify support for latency management, and by the Wi-Fi Display Source in a SET_PARAMETER request to set the latency mode to a new value.

For the purposes of this section, "latency" is defined as the time from the moment the last RTP packet is received for a video frame, until the time that the Wi-Fi Display Sink renders the frame to the output device.

The ABNF syntax is as follows:

    microsoft-latency-management-capability = "microsoft_latency_management_capability:" SP
           ( latency-management-cap / latency-mode ) CRLF
    latency-management-cap = "supported" / "none"
    latency-mode = "low" / "normal" / "high"

Possible values for the latency-management-cap parameter are as follows:

Value

Meaning

supported

Specifies that the Wi-Fi Display Sink is capable of changing the latency mode.

none

Specifies that the Wi-Fi Display Sink is not capable of changing the latency mode.

Possible values for the latency-mode parameter are as follows:

Value

Meaning

low

Specifies that the Wi-Fi Display Sink SHOULD keep latency under 50 milliseconds.<7>

normal

Specifies that the Wi-Fi Display Sink SHOULD keep latency under 100 milliseconds.<8>

high

Specifies that the Wi-Fi Display Sink SHOULD buffer additional frames in order to ensure smooth playback, as long as the latency stays under 500 milliseconds.