absoluteDisplayStart vs absolutePlaybackStart

[mxAlexG]

Hi,
How both properties differ from each other? I am trying to get the tick position value from a Beat instance. The problem however is that the value is useless when there are repeating sections in the score. I would appreciate a clarification.

Regards.

[Danielku15]

The difference is documented on the model:

alphaTab/src/model/Beat.ts

Lines 371 to 381 in 4d8eac9

	/**
	* The timeline position of the voice within the current bar as it is displayed. (unit: midi ticks)
	* This might differ from the actual playback time due to special grace types.
	*/
	public displayStart: number = 0;
	/**
	* The timeline position of the voice within the current bar as it is played. (unit: midi ticks)
	* This might differ from the actual playback time due to special grace types.
	*/
	public playbackStart: number = 0;

It mainly relates to the special handling of grace notes within music notation. Their time when they are played is different from the time they are relatively displayed within the measure.

When you generate a midi out of a score, a special lookup object MidiTickLookup is generated which allows a lookup of a bar/beat given a midi tick position. It can be obtained from the API object through the api.tickCache. As it is rather a low-level API I recommend looking through the code of alphaTab to understand all its details.

[mxAlexG]

Thanks for the clarification.