At Thu, 27 Mar 2003 23:14:22 -0400, Manuel Jander wrote: > > Hi, > > Paul Davis wrote: > > >>When an application opens a mono substream, the sound has to > >>be sent to one channel only or must the low level driver > >>transparently convert it to stereo ? > >> > >> > > > >one channel only. > > > >in ALSA, low level drivers do not do any kind of format > >conversion. that is accomplished (if necessary) by code running in > >user-space, typically part of alsa-lib. the low level driver simply > >advertises the capabilities of the hardware, provides ways to use > >those capabilities, and lets the midlevel code and alsa-lib do the rest. > > > > > > ...but, if you are doing mono playback, your sound driver has to setup > your soundcard to playback on both channels the same mono channel. The > Vortex > driver (still not in the main branch) for example splits the mono signal > on its internal > mixer into 2 identical signals which are feed one into each CODEC channels.
no, please don't do that. in the ALSA, instead of the lowlevel driver, alsa-lib (and oss-emulation module) will do this job. the driver is supposed to inform exactly what it supports. in this case, both channels_min and channels_max will be 2. the difference of configuration will be absorbed by the plug-in of alsa-lib and oss-emulation module. ciao, Takashi ------------------------------------------------------- This SF.net email is sponsored by: The Definitive IT and Networking Event. Be There! NetWorld+Interop Las Vegas 2003 -- Register today! http://ads.sourceforge.net/cgi-bin/redirect.pl?keyn0001en _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
