[wdmaudiodev] Re: avstream pin allocator framing requirements
- From: Tim Roberts <timr@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Tue, 20 Jun 2006 10:07:00 -0700
Nick Dowell wrote:
>
> I'm in the middle of writing my first avstream-based minidriver, and
> have been experimenting with the behaviour of everything. I'm
> confused, though, when it comes to the concept of allocator framing.
>
> I gather from the DDK documentation that I should be able to declare a
> KSALLOCATOR_FRAMING_EX struct and point to it in my pin descriptor,
> and through it specify what frame sizes my pin's process dispatch can
> accept.
>
> DECLARE_SIMPLE_FRAMING_EX(PinFraming,
> STATIC_KS_TYPE_DONT_CARE,
> KSALLOCATOR_REQUIREMENTF_SYSTEM_MEMORY,
> 1024, // Frames
> FILE_BYTE_ALIGNMENT,
> 6, // MinFrameSize
> 6 // MaxFrameSize
> );
>
> Now with these requirements specified by my pin, I'd expect to be
> given up to 1024 frames, each of 6 bytes in size, in one call to my
> process dispatch. What I actually get passed is one frame 8192 bytes
> long, clearly beyond the range I specified.
What sample did you start from? Several of the samples modify the
framing requirements on the fly using KsEdit when the actual pin format
is established.
Is this a source filter, or is there someone upstream? If there is a
filter upstream from you, then it may be that your allocator is
involved. You can be handed the frames they supply.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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