[wdmaudiodev] Re: Record Buffer Issue
- From: "Jerry Evans" <jerry@xxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Thu, 16 Sep 2004 16:07:38 +0100
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
> Hello,
>
> 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, which
is
> just 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 device
can
> do)! 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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