Yes I do understand the theory of this, my problem is that I do not generate the data in the callback, it is generated elsewhere in my code so when I call SndStreamStart it blocks and therefore I cannot get back to my program to get more data and interruptions in the audio occur. Is there a way to get around this? Am I missing something? Thanks Monika
"Ron Nicholson" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > On Mon, 17 Nov 2003 13:29:51, Monika Kauntz writes: > >I am trying to use the extended sound APIs to record data, do some > >processing on it and play out some audio. I am not recording or playuing > >back from a file but using buffers to store the data instead. > >My problem is that for example in playback I do not have all the data to > >play at once and it is not generated in the callback so I get interruptions > >in the playback. > > Read up on packetized and streaming audio. When streaming audio, > one obviously needs to get or generate audio samples at least as fast as > they are being sent to the D/A converter in order not to get any glitches > or interruptions in the sound waveform. If you can't do this, you > can't avoid some interruptions (although telephone company R&D > labs have inventing many techniques for hiding them.) > > When using the PalmOS Sampled Sound API's, if before starting your > sound you have one or two buffers pre-filled, and you keep filling them > at at least the rate your sound callback is emptying them, then your > callback will always have data available to copy to the sound channel to > avoid any glitches or interruptions. Syncronization flags between > the various threads are useful for monitoring the buffer fill and use > rates. > > When processing audio, you need to make sure the input buffers are > filled and processed before passing them to the output channel. The > latency input to output will depend on the sample rate, the packet buffer > length and the speed of processing each packet buffer. > > > IMHO. YMMV. > > Ron Nicholson > HotPaw Productions > http://www.hotpaw.com/rhn/palm > > > > > -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
