On 2004-05-28 19:49:08 +0000 Fred Gleason <[EMAIL PROTECTED]> wrote:
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.
what if you use a buffer {maybe something that would interactively adjust the relative latencies and serve to each card separately.You would have to set time somewhere else. {unless you set your time with one card and fed stuff to the other relative to that.}
