diff --git a/spec/ttml2.xml b/spec/ttml2.xml index 5e15b86ff..7cf974170 100644 --- a/spec/ttml2.xml +++ b/spec/ttml2.xml @@ -23234,12 +23234,15 @@ the rate of playback (or interpretation) of time may artificially dilated or nar playback of a related media object. Without loss of generality, the following discussion assumes a fixed play(back) rate. In the case of variable play rates, appropriate adjustments may need to be made to the resulting computations.

+

The document processing context defines the applicable epoch and any epoch-related offsets +to be used when establishing the synthetic document syncbase.

Clock Time Base

When operating with the clock time base, the following semantics apply for interpreting time expressions, as defined by <time-expression>, and their relationship to media time and local real time.

The clock time base C is related to local real time R -expressed in an arbitrary (implementation defined) epoch E +expressed in the epoch E (defined by the +document processing context) as follows:

@@ -23369,7 +23372,8 @@ during playback, presentation timing is not affected.

When operating with the media time base, the following semantics apply for interpreting time expressions, as defined by <time-expression>, and their relationship to media time and local real time.

The media time base M is related to local real time R -expressed in an arbitrary (implementation defined) epoch E as follows:

+expressed in the epoch E (defined by the +document processing context) as follows:

TTML Semantics – Clock Time and Real Time Relationship
TTML Semantics – Media Time and Real Time Relationship