[LAU] Latency and USB interfaces

[Tim Goetze]

[Clemens Ladisch]
>In most cases, the ALSA buffer/period parameters directly reflect
>hardware parameters, but in the case of protocols like USB where it is
>not possible to transfer data directly out of a ring buffer, there is an
>additional packet queue, which adds latency.  (The length of that queue
>is either constant or proportional to the period size, depending on the
>driver.)

Thanks you Clemens for clearing that up.  How would one go about
determining the size of this queue between ALSA and USB?  

And is it correct to assume that in a best-case scenario where the
sample clock is synchronised to the USB clock and the period size
coincides with the interval at which USB frames are signalled, the
additional latency will be one period? 

Cheers, Tim