On Friday 28 May 2004 15:19, Ivica Ico Bukvic wrote: > Hmm, it would be a fun project then to come up with a profiler of various > audio cards by recording and then capturing a specific buffer of audio > data. Then by comparing them (assuming that this drift is constant) see how > many empty samples there are (or if the playback is slower, how many > samples are missing), and then create a framework that allows real-time > resampling in order to compensate for that discrepancy whenever multiple > soundcards are being used :-D
I strongly suspect that you'd find your results to be non-repeatable. Many factors can subtly influence the output frequency of even crystal-locked SRGs: ambient temperature, power supply voltage variation, even component aging. This issue affects many more applications than just audio. *Any* system that requires precise replication of clock (as, for example, most any digital telecommunication scheme does) faces this dilemma. In the end, some form *locking*, slave clock to master, is needed. A variety of methodologies, such as PLL (phase lock loop) exist to do this, but the bottom line remains that some sort of hardware support will be necessary. Cheers! |-------------------------------------------------------------------------| | Frederick F. Gleason, Jr. | Director of Broadcast Software Development | | | Salem Radio Labs | |-------------------------------------------------------------------------| | I know the answer! The answer lies within the heart of all mankind! | | The answer is twelve? I think I'm in the wrong building. | | -- Charles Schulz | |-------------------------------------------------------------------------|