Clemens Ladisch wrote: >> However, I wish to be able to make the sequencer or player work without the >> use of the ALSA queue nor the workaround in (2). > > Why? Because the queue output and draining, AFAICS, is implemented in a blocking manner. When events are being played by the queue in the kernel, the application blocks, and I have no control on what is being played, except that I could raise a SIGTERM anytime and end the app. AFAIK, using the queue is fine for a simple MIDI player, but not for a sequencer, when you need full control of everything that happens with the audio output. >> How could I get the app to <u|nano>sleep() in the most accurate way in >> userspace without using the ALSA queue nor the extra subscription to an >> output port? > > On newer kernels, you could try POSIX interval timers. What newer kernels? Interval timers, as far as I've tested, result in more latency than simple sleeps. And yes, I've tried select(), which seems to be more accurate than usleep(). >> Or, is there a drain or output routine that supports callbacks? > > Why can't you simply call the callback when some event has been > received? Received by what? By the extra subscription to the output port? As I've mentioned in the original post, I know this works but for now, I'd want to try out simpler sleeps than having an extra output port subscription. The queue blocks when it plays events. Thus, the supposed callback function which, as you suggest, should be called after the event is received, will already be useless since the callback will only be executed once the queue unblocks. Thank you very much. > > > Regards, > Clemens Best Regards, Carlo -- Carlo Florendo Softare Engineer/Network Co-Administrator Astra Philippines Inc. UP-Ayala Technopark, Diliman 1101, Quezon City Philippines http://www.astra.ph -- The Astra Group of Companies 5-3-11 Sekido, Tama City Tokyo 206-0011, Japan http://www.astra.co.jp _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
