play-1.js: add support for metronome + count-in

[joaocc]

Hi,
Do you have anything lined up to (optionally) play a metronome sound on top of the current generated sound?
If this is the case, it would also be great to have a count-in of 1 or 2 bars (ie, just the metronome sound for 1 or 2 bars before starting the visual and audio).
Thx

[moinejf]

I have no use of a metronome, but you can do it yourself: just replace play.js and add the metronome before the call to toaudio5.play (the audiocontext is in 'ac' in the 'conf' object ).

[joaocc]

How would you suggest we sync the metronome beats with the note outputs? Is there any callback that is being triggered on the tempo? Thx

[moinejf]

A simple solution: add a 'metronome' voice.
In your version of play.js, wrap the AbcPlay method 'add()'.
In add(), you get the symbol list which is sorted by time and the voice table.
Then, add a voice, insert the metronome notes in this voice and lnsert these notes at the right time in the symbol list.
For the metronome to start before the tune, shift all the 'time's of the symbols.

[joaocc]

Thx! We will look into that.

[bwl21]

@joaocc did you implement @moinejf's proposal?

[joaocc]

Not yet.
At this moment we have a "plain" metronome playing a bit before.
However, we will probably do a "silent" count-in (1 or 1/2 bar), followed by a 1 bar with metronome, and then start the playalong. Also, at the moment, we don't know if we have the js-fu to implement it the way @moinejf suggested.