[LAU] Intel-hda jack low latency howto

Arnold Krille arnold at arnoldarts.de
Mon Nov 3 03:27:14 EST 2008


Am Montag, 3. November 2008 schrieb Ray Rashif:
> Thanks, Nathan. This is great; I've been scouring for some info on
> optimising Intel HDA for some time already. Btw, is there a reason to be
> using 48000? Like hardware restriction (because that's what I recall from
> one of the quotes from an ALSA developer)? Also, I've read around that 3
> periods are mainly for USB interfaces - any reasoning behind this one?

One of the design decisions of the hda is to support 48 kHz for DVD. And to 
make it simple they only support 48kHz in hardware. While you can open the 
device with lower samplingrates this will get resampled to 48kHz either by 
the driver or the chip. And as you don't know what quality that resampling 
algorithm has (remember the only thing "high" in the hda is the name), you 
will want to use 48kHz from start to end and only downsample to 41kHz 
directly before creating the cd master. Which has the advantage that you can 
use the fine libsamplerate instead...

Have fun,

Arnold
-- 
visit http://www.arnoldarts.de/
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