Play handles

In LMMS, play handles manage playback of notes, instruments, or sample clips. All play handles are managed by subclasses of PlayHandle.

Types of play handles

There are several types of PlayHandles defined:

• NotePlayHandle: manages Notes being played, and get audio output for specific note

• InstrumentPlayHandle: manages instruments which provides per-instrument audio output(single-streamed instruments)

• SamplePlayHandle: manages sample playback

• PresetPreviewHandle

• SampleRecordHandle

Important member variables and functions

• m_offset(type f_cnt_t): The number remaining of audio frames before the play handle starts to produce audio, evaluated at the beginning of a rendering period

Functions which subclasses should implement

PlayHandle itself can't be used directly because it doesn't implement some of the required functionalities.

• play(sampleFrame *buf): Render a period of audio buffer to buf and check/manage the playback state of the managed object

• isFinished(): Return whether the managed object finished playing and this can be deleted

• isFromTrack(const Track *track): Check if the play handle plays objects in the given track