[wdmaudiodev] Re: (No Thread-Topic: [wdmaudiodev]
- From: Tim Roberts <timr@xxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Sun, 3 Jul 2016 18:51:24 -0700
On Jul 3, 2016, at 5:52 PM, 若水 <shlikewater@xxxxxxxxx> wrote:
Hello, I am studying avstream audio driver development. About pin
_KSPIN_DESCRIPTOR_EX, I have some questions.
1 If I only develop a common audio driver, no other effect function, for mic
function, do I need just ONE capture pin?
Correct.
2 How to set Flags in pin descriptor? When I start a recorder application, I
want to get the data at Pin::DispatchProcess function. But I don't know how
to set the flags.
Well, for a microphone, you don't get data in the Process function, you get
empty buffers. It's up to you to put data in them. Sometimes that's done in
Process, sometimes that's done in a separate routine triggered by hardware
activity.
Look over the individual flags and see what you think. You often want to know
every time a new empty buffer arrives, so
KSPIN_FLAG_INITIATE_PROCESSING_ON_EVERY_ARRIVAL is often useful. If your
hardware will be doing DMA transfers, you may want KSPIN_GENERATE_MAPPINGS.
Beyond that, you may not need any others.
3 How to set KSALLOCATOR_FRAMING_EX in _KSPIN_DESCRIPTOR_EX? If my mic
hardware is 2channels, 16bits, 48000samples, and I use
DECLARE_SIMPLE_FRAMING_EX to realize KSALLOCATOR_FRAMING_EX, how to set the
Frams, MiniFrameSize and MaxFrameSize?
If you don't care about buffer sizing or locations, then set that member to
NULL. In that case, the graph will decide the buffering based on other
requirements.
—
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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