On Sun, 1 Feb 2004 11:29:15 +0000 (GMT),
=?iso-8859-1?q?vikram=20sonawane?= <[EMAIL PROTECTED]> wrote:
>hello,
> i'm having a problem using SndStreamCreate for
>recording....Can n e one give me a WORKING sample code
>
>demostrating the working of sndstreamcreate.i'm using
>Tungsten T simulator....
>thanx,
My application is too big to post, but the essentials are these:
The sound stream is opened with:
Err error = SndStreamCreate(&soundStream,
sndInput,
11025, //NominalSamplesPerSecond
sndInt16Little,
sndMono,
soundInCallback,
(void*)&Ibufptrs,
2048, //RequestedBlockSize,
0); //..0 = callback is NOT ARM..
where the call back is:
Err soundInCallback(void *userData,
SndStreamRef stream,
void *buffer,
UInt32 frameCount)
{
Int16 *p;
p = ((BufPtrs*)userData)->bufCurrent;
if(p)
{
MemMove(p,buffer,RequestedBlockSize*sizeof(Int16));
p += RequestedBlockSize;
if(p >= ((BufPtrs*)userData)->bufPastEnd)
p = ((BufPtrs*)userData)->bufOrigin;
((BufPtrs*)userData)->bufCurrent = p;
EvtWakeup();
}
return errNone;
}
where the BufPtrs structure is defined by:
typedef struct {
Int16 *bufOrigin;
Int16 *bufPastEnd;
Int16 *bufCurrent;
} BufPtrs;
Then, I field the nilEvent in the main form event handler:
case nilEvent:
CheckSoundCallback();
break;
where CheckSoundCallback() is defined by:
void CheckSoundCallback(void)
{
Int16 *p;
p = Mbufptrs.bufCurrent;
while((p!=Ibufptrs.bufCurrent) && Ibufptrs.bufCurrent)
{
/*--process Mbufptrs.bufCurrent--*/
//..then:...
p += RequestedBlockSize;
if(p >= Mbufptrs.bufPastEnd)
p = Mbufptrs.bufOrigin;
Mbufptrs.bufCurrent = p;
}
}
In this way, the callback does minimal processing, and leaves all the
heavy lifting to the event handler.
Robert Scott, Ypsilanti, MI
(reply through this forum, not by e-mailing me directly)
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