[wdmaudiodev] Re: GetMappings and GetPosition in WavePCI
- From: "Frank Berreth" <fberreth@xxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Wed, 28 Aug 2002 11:48:52 -0700
It seems to me you are releasing the mappings out of order. Win2k does
check the order (which is kind-of a bug) and WinXP just doesn't care.
So make sure you release the mappings in order.
This posting is provided "AS IS" with no warranties, and confers no
rights.
-----Original Message-----
From: fox friend [mailto:foxfriend@xxxxxxxxx]=20
Sent: Tuesday, August 27, 2002 6:21 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] GetMappings and GetPosition in WavePCI
i encounted a strange problem in writing WavePCI
driver.=20
if i start to play a wave file in media player, i can
get some mappings from system and play. what happened
to me is that the stream will play the wave file
correct for the first 2 seconds, however the third sec
will repeat the 2nd second's contents. then the system
will stop and destroy this stream, then open a new
one. nevertheless, the same thing will happen again.
it always plays 2 seconds correctly, then repeat the
2nd second in the 3rd second. what's more, in the end
of this wave, it will keep playing the last second's
audio data without calling a stop. what happened here
is when i call GetMapping, system will keep giving the
same audio data instead of giving me an error
NTSTATUS. so the last stream won's stop.=20
if i start to play wave in sound recorder, it just
stay at the beginning, and won't move forward at all.
i will only get 5 small mappings here. after i release
them, when i call getmappings again, it won't give me
any more. GetPosition will be called only once before
the status becomes RUN.
once, i thought it was a problem related to
GetPosition. but even though i used timer to calculate
how much it should have played, the same thing would
still happen. this timer was calculated according to
the system time passed, sample size, sampling rate
etc. i did doubt whether it is because of GetPosition.
to clarify it, i once asked system for large trunk of
data, around 0x50000 bytes, at the initial stage
before Run (using media player). to my surprise, the
system did not reject me, it did give me data. however
the same thing happened again. this large trunk of
data was sufficient for system play around 4 seconds.
when i checked those data, it had already contained
the repeated data.
then i did the whole thing in the opposite way. i just
asked for small amount of data when each interrupt
came, then played it immediately (still using media
player). this amount of data was only enough for one
and half interval between two interrupt. however what
i saw was the same thing again.
the more funny thing is the driver i wrote can work
under XP using windows media play, while fail in
win2000. however in both case, the soundrecorder won't
play. it just stays at the beginning place. when i=20
check the output message, the system still gives me
only 5 small Mappings before the Run status in the
initial stage. after that, though my driver keeps
asking for new GetMapping, system will not give any
more data. (i do releast those 5 Mappings)
i really don't know why. is it still about GetMapping
or GetPosition. thank you for any forthcoming reply.
regards
Fox
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