[wdmaudiodev] Re: AW: DirectSound and XXDVD Strange behavior
- From: Nick Gorohov <engkosha2001@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Mon, 18 Oct 2004 08:52:46 -0700 (PDT)
Dear David!
1) correct, The App does not do that.
2) True; DSound can ( and in some cases will ) insert
"silence pack" ( buffer with 0's ) into stream, so, driver
may receive such 0 packs from "nowhere". Wave driver
will never do that.
It should not be a problem for you, just ignore this packs
and continue search for the spdif header key-word. Microsoft
is slowly going to the idea with never stopping audio on PC;
that means, they will never fix this for you (I mean silence
insertion)
Nick Gorokhov
--- david lee <davidlioncity@xxxxxxxxxxxx> wrote:
> Dear Nick,
>
> Yes, I do agree with what you said. Okay, It is better to give an example to
>
> clarify the situation what I met. Basically, I get one SPDIF package, for
> example, 6144bytes for AC3 data, by call GetMapping. However, by following
> GetMapping call, I get all zero data and there is no any SPDIF header for
> these data. Thus:
> 1) These data are sent by Applications. But it looks like impossible because
> all data sent by application will be packaged, which means that I will get
> SPDIF Header.
> Either,
> 2) DSound insert these data. But I really cannot understand why DSound will
> insert these data. According to DDK documents, if portclass do not have
> enough data send to miniport driver, it will
> repeat the buffer which it holds. Therefore, I should not get all these zero
> data while the repeated buffer.
>
> BTW Can any application guys or Microsfot guys give comments?
>
> David
>
> Nick Gorohov <engkosha2001@xxxxxxxxx> wrote:
> Dear David!
>
> I am Audio Filter designer at Sonic ( www.sonic.com ).
> Yes, we do that with SPDIF: the beginning is real portion
> of the spdif data ( the real amount is in data header),
> the rest filled with 0's. The trick is that a whole pack
> of data has the same number of audiosamples that
> unencrypted ( PCM ) pack will have. So, can ignore all
> these 0's.
>
> Regards,
>
> Nick Gorokhov
>
>
> --- david lee wrote:
>
> > Dear Stephan,
> >
> > In fact, I set theConnectionInterface.Id =NULL, then what is the default
> > value.
> >
> > According to what you say, as long as I update the position, the port class
> > will send more valid data to me. Am I correct?
> >
> > Thanks
> > Stephan Kappertz wrote:
> > You should check the pins ConnectionInterface.Id when the pin is created.
> > Most likely the ConnectionInterface is
> KSINTERFACE_STANDARD_LOOPED_STREAMING.
> > This means that your driver receives just one valid circular buffer when
> > playback starts. It is supposed to loop through this buffer until playback
> > stops. The current DMA position that your driver reports will be used to
> > update the portion of the circular buffer with new data that is currently
> NOT
> > played.
> >
> > Stephan
> >
> >
> >
> > -----Ursprüngliche Nachricht-----
> > Von: wdmaudiodev-bounce@xxxxxxxxxxxxx
> > [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] Im Auftrag von david lee
> > Gesendet: Monday, October 11, 2004 11:35 AM
> > An: wdmaudiodev@xxxxxxxxxxxxx
> > Betreff: [wdmaudiodev] DirectSound and PowerDVD/WinDVD Strange behavior
> >
> >
> > Dear all,
> >
> > When I use PowerDVD/WinDVD SPDIF pass through and select direct sound audio
> > render, I always get a lot of zero data with a few valid data in the
> > beginning of playback. Due to use driver to decode the AC3/DTS data, I am
> not
> > sure how to handle these zero data. Any suggestion? (Treat them as data
> need
> > to be decoded or as rubbish and discarded)
> >
> > BTW, if I select waveout audio render, All the data at the beginning are
> > useful valid data,which I can decode.
> >
> > Thanks in advance
> >
> > David
> >
> > Yahoo! Mobile
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> >
> > Yahoo! Mobile
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>
>
>
>
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