192kHz PCI audio card with a 16-channel scatter-gather engine. See
http://www.lynxstudio.com/aes16.html. I support up to 8 cards per system
for a total of 128 input channels and 128 output channels. US$695/each.
You can get a demo in London at HHB ;-).
Thank you,
David
Hi David
Sorry, this is peripheral to your question: can you tell me what audio hardware you are using here ?
Thx
Jerry
----- Original Message ----- From: "David A. Hoatson" <dhoatson@xxxxxxx>
To: <wdmaudiodev@xxxxxxxxxxxxx>
Sent: Thursday, September 16, 2004 3:30 PM
Subject: [wdmaudiodev] Record Buffer Issue
isHello,
I have noticed some specific behaviour for recording that is causing major
grief for my audio driver (IMiniportWavePci/IMiniportWavePciStream).
For playback, the buffers are chopped up into 10ms increments and it seems
that a maximum of about 3 buffers are sent down to my driver from the WDM
port class driver. If the sample rate scales up, so does the buffer size
so each buffer is still 10ms in length. Playback at any sample rate works
as expected.
For recording, eight 64-byte buffers are passed in regardless of sample rate. At 48kHz stereo, this means each buffer represents ~0.66ms, whichcanjust at the limit of what gives acceptable performance from faster machines. At 192kHz, the port driver still only gives eight 64-byte buffers, so now that same buffer only represents 0.166ms for stereo, or only 1 sample period for 16 channel interleaved 32-bit (which my devicedo)! This means the PC is not able to respond to each interrupt fast enough and audio breakup will occur in only 1.3ms (192kHz/Stereo). This essentially means that recording through the port class driver is not possible at higher sample rates/higher channel counts. I should mention that I am using Windows XP SP2.
So far I have found nothing that allows my driver to control the size or
number of buffers that are passed in from the upper level driver. Does
anyone have a solution to this problem? I'm sure there is something very
basic that I am missing...
Thank you,
David
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