Re: [LAD] Library for accurate time stamping using a DLL

Hi everyone, Fons, thanks to your essay "Using a DLL to filter time" [1], that you mentionned in a discussion we had in August, I've put together a small library, named Pendule, for accurate timing within a real time context. It's a tiny piece of code, but offers a very easy to use replacement for gettimeofday(). Plus, it includes some benchmarking/measuring tools, that produce that sort of fancy graphics (this one using a PCI hda intel card): http://www.samalyse.com/code/pendule/shortgraph.png Usage is very simple. first create an instance: #include <pendule.h> Pendule *pendule = pendule_new(buffer_size / sample_rate, bandwidth); Then, in the realtime thread, update the loop every process cycle: pendule_cycle(pendule); And use pendule_gettime() instead of gettimeofday(): double current_time_in_seconds = pendule_gettime(pendule); As expected, looking at the graph above, the obtained time doesn't drift as the audio time, and has a lower jitter than the system time. Well, at least, it works for me. However, although my measures are pretty encouraging, I am not 100% sure of my DLL implementation. Could you please review it ? It's there: http://svn.samalyse.com/pendule/trunk/src/pendule.c

You can grab everything using svn: svn co http://svn.samalyse.com/pendule/trunk pendule I'd like to know how it works for others. You can easily test your hardware/system and make graphs with: ./waf configure ./waf build ./measure ./graph Check the README for more. [1] http://www.kokkinizita.net/papers/usingdll.pdf Best regards,