Takashi Iwai wrote: >At Fri, 04 Oct 2002 01:10:50 +1000, >James Courtier-Dutton wrote: > > >>Hello >>I have searched the web to find the specs on this chip. No Luck. >>What I have found is that it is a Yamaha OPL3-SA2 or YMF711. >>Which playback rates does it support ? >> >> > >the dma engine of opl3sax is actually cs4231-compatible. >thus it supports the following sample rates: > 5510, 6620, 8000, 9600, 11025, 16000, 18900, 22050, > 27042, 32000, 33075, 37800, 44100, 48000 > > > >>I find that anything above 32k causes jittery playback. >> >> > >most likely you hit a bug ;) > >how is the symptom exactly? repeated (stutter) sounds? > > >what i heard about this chip is that the pcm is not audible until a >pcm mixer element is modified at each open. >but it looks like a different problem... > > >ciao, > >Takashi > > > > I think the problem is that the sound buffer is filled by the application, but then on a slow PC, the CPU is locked into doing something with the X display (XV video images), and the transfer inside alsa-lib from buffer to sound card does not get CPU time. So, basically samples are lost.
So, if I was to send 3 groups of samples to the sound card, A,B, C. The alsa-lib buffer is then filled with A,B,C, but the sound hardware grabs a period, so takes A and plays it, but when the sound card comes to get B, it does not have the CPU time, so the sound card just plays silence, when the sound card gets CPU time, it then plays B, then plays C, but as it played B and C late, my application tries to resync and drops D and then sends E to the sound card. Is there any reports in alsa to report missed interrupts to the application ? I understand that an "underrun" is when the interrupt gets CPU time, but the application is not up to speed, but what if there is too long a delay between the sound card signalling an interrupt, and the interrupt routine actually being run ? The sound card hardware will not get the samples it needs, but "underrun/xrun" is not sent back to the app. Cheers James ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
