How to implement looping using the MIDI player ?

[arcln]

Hello,

I'm trying to loop a MIDI file from and to a specific tick using the Fluidsynth API.
I started from the Loading and playing a MIDI file code base, which works just as expected.

In order to call fluid_player_seek() and make the MIDI loop, I need a callback that is executed on every tick, which I didn't find.
I did find the fluid_player_set_playback_callback() function however :

• It is only called for MIDI events, so if there is no event on the tick I want to loop, the loop will be delayed until the next event.
• When it reaches the last tick (fluid_player_get_current_tick() == fluid_player_get_total_ticks()), the MIDI is removed from the play queue so audio is stopped despite a call to fluid_player_seek(..., 0)
• Even when adding the audio again using fluid_player_add(), I need to wait the next "call" to be able to use fluid_player_seek(), which is very inconvenient.

How can I implement this?

Thanks!

[derselbst]

The MIDI player hasn't been designed for such precise control. Feel free to propse changes to fix those quirks. However, I see no way of getting a callback on every tick.

Alternatively, you could consider to use the sequencer API instead. There, you can schedule timer events that give you a callback at a very certain tick. However you'll have to "emulate" the seeking yourself. I'm doing something like that together with libsmf in my app, to support MIDI track loops. But here I know when loop will happen as this is indicated by a CC. So not sure if this suits your use-case at all.

[arcln]

Hi,

Thanks for your reply. I read the code in your app, and it indeed fixes the problem I was facing.
However, considering the amount of logic and additional state it creates, and considering most of this logic is already present in fluid player, I decided to implement a per-tick callback in the player.

I PR'd this in #780.