Sorry, a re-send. Reply to was set to the sender and not the group. On Saturday 13 February 2010 12:42:56 pm Peter Hamilton wrote: > > Since you didn't specify a M$ OS > > No, I specified Linux: > >> 3.13BX, Portaudio, Xubuntu 9.10. > > See other message to Dave for more detail. Problem now fixed by > switching from Portaudio to OSS. I don't have a clue why, but all works > as expected with OSS.
Sorry, didn't see the reference. But the loading was as I expected. The reason for the difference is in the efficiency of the sample rate converter. In my experience the OSS sample rate converter is a lot more efficient than the converter built into PortAudio for certain sample rate conversion ratios. That is compounded by the 44100 native sample rate of the card. I suspect that a card that had a native sample rate of 48000 would not have loaded the PortAudio sample rate converter as badly. It's better to have a soundcard that supports any of the sample rates needed by the application natively, but these are increasingly hard to find these days. It might be interesting to see how Pulse handles this. The quick fix is probably to use OSS emulation on these cards that have a higher sample rate conversion overhead. I had one card like this that I was using on a machine that had plenty of CPU overhead so I didn't care about the additional loading. But it just was not as sensitive and some of the digital modes such as Olivia refused to decode correctly using the PortAudio sample rate conversion routines to 44100. Using OSS the CPU load dropped and everything decoded fine. Rick Kunath, k9ao _______________________________________________ fldigi-alpha mailing list [email protected] https://lists.berlios.de/mailman/listinfo/fldigi-alpha
