[alsa-devel] Source of timing for MIDI and/or audio synchronization
marr at lumin.us
Tue Jun 12 08:17:57 CEST 2007
Hello (new to list), and thank you for the work you have been doing. As
an end-user of the ALSA project's development, I am very grateful for
being able to use softwares which provide audio functionality to Linux.
I have been reading up on the docs and list archives, but I still have
an open question for which I hope you can lead me to an answer.
I designed and built a MIDI sequencer based around a Microchip PIC18
MCU, and used the built-in hardware timers and interrupt levels to drive
the 'scheduler' for initiating MIDI output (EUSART) routines. In this
same vein, I would like to write a software sequencer with as 'tight'
timing as possible. So, in a similar concept for Linux - from where does
the timing of audio and MIDI events come from?
It occurred to me that it would be nice to have a loadable kernel module
(LKM) to which userland programs could subscribe for receiving 'soft
interrupts' based on some timer (cpu ticks?) so that various software
could all reference the same notion of the "current time" - a sort of
"master clock" with start/stop/continue as well.
Does ALSA provide this functionality? Can someone point me in the right
direction for learning more about this?
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