Module utc_timing 

UTCTiming schemes and the client-measured clock sample.

ISO/IEC 23009-1 5.8.5.7 Table 35 names the schemes; the sampling rule (midpoint of the request/response exchange, uncertainty = half the round trip plus the time source’s own resolution) is docs/dash-runtime/DESIGN.md 3.3. The caller measures sent_us and received_us on its own monotonic clock; nothing here reads a clock.

Structs

Exchange

The request/response pair the caller timed on its monotonic clock.

UtcSample

One clock measurement: at monotonic mono_us the UTC time was utc_us (Unix microseconds), give or take uncertainty_us.

Enums

UtcScheme

A UTCTiming scheme (Table 35).

Constants

DATE_HEADER_HALF_SECOND_US

Date carries whole seconds (RFC 9110 5.6.7): the sample is taken at the middle of the second and the half second is added to the uncertainty.

HTTP_NTP_RESOLUTION_US

Resolution of an NTP timestamp read over HTTP, in microseconds.

SCHEME_DIRECT

5.8.5.7: urn:mpeg:dash:utc:direct:2014.

SCHEME_HTTP_HEAD

5.8.5.7: urn:mpeg:dash:utc:http-head:2014.

SCHEME_HTTP_ISO

5.8.5.7: urn:mpeg:dash:utc:http-iso:2014.

SCHEME_HTTP_NTP

5.8.5.7: urn:mpeg:dash:utc:http-ntp:2014.

SCHEME_HTTP_XSDATE

5.8.5.7: urn:mpeg:dash:utc:http-xsdate:2014.

SCHEME_NTP

5.8.5.7: urn:mpeg:dash:utc:ntp:2014.

SCHEME_SNTP

5.8.5.7: urn:mpeg:dash:utc:sntp:2014.

UTC_BODY_MAX_BYTES

Largest UTC response body read (DESIGN risk R3).

Functions

sample_from_body

Sample from the body of an http-xsdate, http-iso or http-ntp response.

sample_from_date_header

Sample from the Date header of an http-head (or any) response.

sample_from_direct

Sample from a direct scheme @value, taken at the midpoint of the MPD response exchange.

sample_from_exchange

Build a sample from a timed exchange and the server time it returned.