[wdmaudiodev] Re: Capture latency with USB card

  • From: "Jerry Evans" <jerry@xxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Wed, 25 Jun 2003 17:18:04 +0100

Hi Pierre. I assume that the figures you are quoting are measured end to end ? 
What buffering latency does your KS code impose ? I found I was getting 
similiar numbers with the latest WinXP USB drivers and USB1 audio devices.
  ----- Original Message ----- 
  From: Pierre Brisson 
  To: wdmaudiodev@xxxxxxxxxxxxx 
  Sent: Wednesday, June 25, 2003 3:14 PM
  Subject: [wdmaudiodev] Capture latency with USB card


  I am writing an application using KS. The application allows users to monitor 
the input.
  With a PCI card, I get delays down to 6-7 ms (measured with a signal 
generator and a scope).
  With a USB audio device though, the minimum stable delay I can get is around 
20-25 ms.
  The cause of the problem seems to be the instability of the capture side. I 
measure the time
  between capture events and I get delays up to 20ms on USB where it should be 

  I am using Microsoft USB audio driver (latest version) and I heard that it 
can achieve better
  performance. Did anybody experienced such problems with USB audio? 



  Pierre Brisson
  Adacel Inc.
  450-672-3888 ext 335

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