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MusicSequenceSetSequenceType(_:_:)

Sets the sequence type for a music sequence.

Declaration

func MusicSequenceSetSequenceType(_ inSequence: MusicSequence, _ inType: MusicSequenceType) -> OSStatus

Parameters

  • inSequence:

    The music sequence whose sequence type you want to set.

  • inType:

    The type of sequence to assign to the music sequence. For the list of available sequence types, see Musicsequencetype. The default sequence type is kMusicSequenceType_Beats.

Return Value

A result code.

Discussion

The sequence type can be set to kMusicSequenceType_Beats at any time. The sequence type can only be set to kMusicSequenceType_Seconds or kMusicSequenceType_Samples if there are no tempo events already in the sequence.

The following considerations pertain to the various sequence types:

  • kMusicSequenceType_Beats—Tempo is specified as beats-per-minute. A music sequence of this type can contain any number of tempo events.

  • kMusicSequenceType_Samples—Tempo is specified as a sample rate, in terms of samples-per-second. If you set the tempo to 44,100 using a sequence of this type, then 44,100 beats corresponds to a duration of one second.

  • kMusicSequenceType_Seconds—The tempo should be set to 60; a beat is a second.

After setting a music sequence to the kMusicSequenceType_Samples or kMusicSequenceType_Seconds type, add a single tempo event to specify the tempo.

A meta event of interest for the kMusicSequenceType_Seconds sequence type is the SMPTE Offset meta event, which is stored in the tempo track. The sequence doesn’t do anything with this event.

See Also

Managing Music Sequences