[linux-audio-user] Python & ALSA --- documentation

[Rob Fell]

Rob Fell wrote:
> Peter Brinkmann wrote:
> 
>>> Would this work for you?
> 
>  > Almost.  I see no need (in my application) to ensure that the GUI
>  > events are serialised at the correct time in the event stream.
>  >
>  > I favour a periodic callback since a timeout on poll() indicates that
>  > there are no events pending - hence it would be a reasonable time to
>  > handle GUI events.
> 
> That's essentially what midiplayer.py does. Since most MIDI files
> contain a lot more events than can be scheduled at once, midiplayer.py
> just schedules a batch of a few hundred events at a time, followed by
> an echo event addressed to itself. Then it just sits around waiting
> for this echo event to arrive, at which time it schedules the next
> batch as well as another echo event, etc.
> 
> In your situation, you may just want to set things up in such a way that
> the MIDI thread keeps sending itself echo events at regular intervals.

IIUC in the case of midiplayer.py, all the events are generated by 
software: in my case I'm trying to merge a live stream from a physical 
device with events generated either by other physical devices or via the 
GUI.  GUI interaction should stall whilst there are real events to 
process - and the easiest way I see to handle this is to use the poll() 
timeout.

I can try other means of thread synchronisation, but I fear that will 
massively complicate the locking :(

R