[wdmaudiodev] Re: firewire audio at low latency
- From: "Evert van der Poll" <e.j.van.der.poll@xxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Mon, 8 Sep 2003 22:35:55 +0200
Hi,
I'm no expert on drivers for audio devices but I work with them. I would say
that a latency of 200 samples is not great but it's a decent score. The
minimum latency that can be attained depends on your system setup as well as
on the driver code. There are some Windows settings that can be tweaked to
get better performance.
For instance this link gives some tips for Windows 98 setup:
http://www.rme-audio.com/english/techinfo/lola.htm
There are others but it all depend on your OS.
My own soundcard offers me a minimum latency of 128 samples which is
perfectly workable for anything I want to do with it.
There are soundcards around that offer even smaller buffersizes like 64
samples. Yet I think that 50 samples is a pretty ambitious goal and I'm not
sure if that is at all within reach for a firewire device. Is it really
necessary to have these low latencies?
Evert
-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx]On Behalf Of Uwe Kirst
Sent: Monday, September 08, 2003 5:04 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] firewire audio at low latency
Hello,
I'm having some trouble getting low latencies with our firewire
minidriver. It comunicates directly with the 1394 stack by attaching
buffers of the same size using stream based dma.
i) attaching 200 or more samples / buffer @44100kHz works fine.
ii) attaching 100 samples / buffer:
The isoch listen callbacks are not spaced equidistantly any more. From
time to time two callbacks are coming at the same time. In that case one
of the next listen callbacks is missing. The avarage number of listen
callbacks seem to be still ok.
iii) attach 50 samples / buffer:
sometimes, depending on the cpu load, an isoch talk callback is missing.
I'm wondering if someone has similar experince or can explain how they
are working around this issue.
Thanks in advance!
Uwe
******************
WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
URL to WDMAUDIODEV page:
http://www.wdmaudiodev.de/
******************
WDMAUDIODEV addresses:
Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx
Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe
Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe
Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx
URL to WDMAUDIODEV page:
http://www.wdmaudiodev.de/
Other related posts:
