tt element merging rules clarification

[kozmaz87]

I am looking for the specific rules to merge the tt element

def merge(self, other, dataset):
    # TODO: compatibility check, rules of merging TBD
    # merged_tt = tt_type(
    #     lang=self.lang,
    #     extent=self.extent,
    #     timeBase=self.timeBase,
    #     frameRate=self.frameRate,
    #     frameRateMultiplier=self.frameRateMultiplier,
    #     markerMode=self.markerMode,
    #     dropMode=self.dropMode,
    #     clockMode=self.clockMode,
    #     cellResolution=self.cellResolution,
    #     sequenceIdentifier=self.sequenceIdentifier,
    #     sequenceNumber=self.sequenceNumber,
    #     authoringDelay=self.authoringDelay,
    #     authorsGroupIdentifier=self.authorsGroupIdentifier,
    #     authorsGroupControlToken=self.authorsGroupControlToken,
    #     authorsGroupControlRequest=self.authorsGroupControlRequest,
    #     referenceClockIdentifier=self.referenceClockIdentifier,
    #     _strict_keywords=False
    # )
    # return merged_tt

[kozmaz87]

What is the decision on this?

[nigelmegitt]

We need to do more analysis I think. This is for merging two part 3 documents? That is not actually required or specified functionality; we only do it in the context of splicing prior to onward conversion. However I think we still need to answer it.

We need attribute-by-attribute rules I think. In some cases part 3 constrains them to be equal, like clockMode; in other cases you can come up with a common denominator type rule, e.g. tts:extent, but in some cases there might be no sensible answer, and it may actually be an error condition - authorsGroupControlToken for example.

[nigelmegitt]

Is this still something we still need to do? Can it be written as a user story? It would help to know what the merge circumstances are.