[wdmaudiodev] Re: AVStream Capture question
- From: Harry Graham <harry_graham@xxxxxxxxxx>
- To: "'wdmaudiodev@xxxxxxxxxxxxx'" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Thu, 17 Jul 2003 17:09:32 -0700
Wade,
I suggest you set KSPIN_FLAG_INITIATE_PROCESSING_ON_EVERY_ARRIVAL, and call
KsPinAttemptProcessing from the DPC.
In the AvStrProcess routine, you can clone/lock the leading edge stream
pointers as needed, or until the lock fails.
In my design I limit the maximum amount of data queued up at any point in
time, to prevent the system from doing something stupid, like queuing up all
the physical memory in the system. So I will return STATUS_PENDING from
AvStrProcess if I think there is enough data queued, so that AvStrProcess is
not invoked again until my DPC executes, or there is another frame sent to
the stream.
In the case where AvStrProcess is invoked, if
KsPinGetLeadingEdgeStreamPointer or KsStreamPointerClone fail, I return
STATUS_SUCCESS, so they are retried immediately. If KsStreamPointerLock
fails, I return STATUS_PENDING, as there is no point in invoking
AvStrProcess again, until another frame arrives.
Harry
-----Original Message-----
From: wade [mailto:wdawson61@xxxxxxxxx]
Sent: Thursday, July 17, 2003 1:01 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: AVStream Capture question
Harry:
Thanks for your response. A question though. In you opinion, should I set
the KSPIN_DESCRIPTOR.Flags (KSPIN_FLAG_INITIATE_PROCESSING_ON_EVERY_ARRIVAL)
to force a call to my AvStrProcess() when new frames arrive? I'm assuming
this way I can fill newly arriving frames with any data that may not have
fit at DPC time (if, for instance, KsStreamPointerAdvanceOffsets caused
queue run off) . I'm assuming that the arrival of a new frame should trigger
me to transfer the rest of the data that the DPC's Processing call couldn't.
In the case of no data lying around from the last DPC (it all fit in the
available frames the time DPC called KsPinAttemptProcessing()) ) I'm
assuming that I should just return STATUS_PENDING, and return STATUS_SUCCESS
when I fill and complete frames?
Thanks for your help.
Harry Graham <harry_graham@xxxxxxxxxx> wrote:
Wade,
There are many different ways to use the stream pointers in AVStream. I
have not personally used KsStreaPointerGetNextClone, but I suspect that this
is causing your problem.
I would suggest calling KsPinAttemptProcessing from the DPC, and perform all
the stream pointer manipulation and hardware queuing in the Process
callback.
Harry
-----Original Message-----
From: wade [mailto:wdawson61@xxxxxxxxx]
Sent: Wednesday, July 16, 2003 5:01 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] AVStream Capture question
Hi:
I'm writing a capture-only AVStreams driver for a simple piece of hardware.
I get an ISR dispatch and queue my DPC to move x samples to AVStream frames.
In my AvStrMiniProcess (called on every frame arrival and loosely based on
Avshws) routine I am advancing through the Avstream queue cloning pointers
to each frame. I return STATUSS_SUCCESS on the frames I'm able to clone and
STATUS_PENDING on the ones I can't. In my DPC I step through the Clones
using KsStreamPointerGetNextClone(), filling the frames and deleting the
clone pointers as the frame is filled.
KSStudio never shows the frames being completed. KS's dispatch timer is
canceling them.
Is there an easier or better way to do this? I'm about ready to break down
and allocate a NonPaged buffer for my DPC to put samples in and fill the
AVStream frames as they arrive in my AvStrMiniProcess routine. Any help is
greatly appreciated.
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