9 Jan
2014
9 Jan
'14
2:26 p.m.
[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