On Sat, 27 Mar 2004 14:36:31 -0500, Robert Reif wrote:
Another problem is that drivers support different formats in different modes. Because of software emulation in alsa, a driver may appear to support any format but then fail when you try to mmap it because then software conversions can't come into play.
I talked with one of the ALSA developers on IRC a day or two ago, and he appeared to think mmap would work regardless of what plugin chain was in use (resampling/conversion is implemented in alsa plugins). He said if it didn't work it was a bug.
Anecdotal evidence seems to suggest this works now too. I was playing 22khz/8bit sample - the winamp demo file - on my i810 card and it was using MMAP access yet still able to play (for a few seconds before bailing with an assert in alsalib).
IIRC in XP DirectSound primary buffers no longer correspond to the sound cards memory, they are just like any other and sent to the XP kernel mixer. Is it possible the same is now true of ALSA?
thanks -mike