> Is there some way to test the cards and measure their frequency? If > so, you could do a pretty full-blown NTP for sound cards and that > would be pretty freakin cool.
I know when programming the old SoundBlaster 16 cards they would trigger an interrupt when they switched output buffers (so you could fill up the next buffer with data ready to be played), so presumably you could use something like this to accurately time how long it takes to play a sound, which should allow you to measure the frequency. I would've thought though that if you had a software buffer of X milliseconds, then you should be sending that buffer to the card every X milliseconds (according to some other timer in the system.) If it takes longer before the card is ready for the next buffer then you need to drop some samples before sending the buffer to the card, and if the card wants the next buffer sooner than X milliseconds after the last one you'll need to add some samples. Sure, it wouldn't be audiophile-level quality, but it'd be enough for anyone who's happy with a couple of $10 sound cards in their system... Cheers, Adam. ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
