[wdmaudiodev] Re: DMA mode?
- From: Pallavi Joshi <pallavi.v.joshi@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Wed, 12 Aug 2009 09:39:08 -0700
Hi Tim,
One last question, can you suggest a way of speeding things up in my case?
As I said my output (rendering) takes more time than my input (capturing).
My output is asynchronous while input is synchronous.
Thanks,
Pallavi
On Tue, Aug 11, 2009 at 5:54 PM, Pallavi Joshi <pallavi.v.joshi@xxxxxxxxx>wrote:
> I meant the kernel streaming buffers that I am handing to usbaudio.sys
> through IOCTL_KS_WRITE_STREAM.
> Yah, I know I can't overwrite them. The problem is that the
> playback(render) takes much longer than the capture operation. Hence the
> overwriting issue. I wanted to speed up the playback operation by using DMA
> buffers, but that is already in place looks like!
>
> Anyways, thanks a lot for replying.
>
> Pallavi
>
>
>
>
>
> On Tue, Aug 11, 2009 at 5:45 PM, Tim Roberts <timr@xxxxxxxxx> wrote:
>
>> Pallavi Joshi wrote:
>> >
>> > Yup, I meant reducing the latency! Thanks so much for replying. This
>> > is easy then :)
>> >
>> > The main issue that I am facing is that I overwrite the playback
>> > buffer with new data before my previous data has finished playing.
>> > This is what MSDN documentation says about asynchronous IO:
>> > "Do not deallocate or modify the OVERLAPPED structure or the data
>> > buffer until all asynchronous IO has been completed."
>> >
>> > Due to this, I get missing data in my audio stream. Do you have any
>> > suggestions?
>>
>> I'm not sure, you have a lot of concepts mixed up here. Which playback
>> buffer are you overwriting? Is it the application buffer that is being
>> handed to your ASIO driver? Is it the kernel streaming buffers you are
>> handing to usbaudio.sys through IOCTL_KS_WRITE?
>>
>> The advice is good: you can't start reusing a buffer until you know the
>> guy beneath you is finished with it, but the exact definition of
>> "finished with it" depends on which level you're at.
>>
>> --
>> Tim Roberts, timr@xxxxxxxxx
>> Providenza & Boekelheide, Inc.
>>
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>
>
> --
> Pallavi Joshi
> (480)-280-2017
>
--
Pallavi Joshi
(480)-280-2017
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