Owen.yan wrote: > > Dear sir: > Hi Owen, This is a mailing list so there really isn't an individual person you are contacting. I don't represent alsa, just giving advice as I can. > > Does alsa has any tools that can reduce music’s sample rates or > increase it. > alsa includes the dmix plugin by default, and this does crude resampling (linear interpolation) automatically. One external command line tool is sox, that under the covers uses libsamplerate. The audacity sound editor also includes this functionality with its own library. Both of these are capable of much better quality but aren't done on the fly like the dmix plugin does. http://www.mega-nerd.com/libsndfile/ http://www.mega-nerd.com/libsamplerate/ http://sox.sourceforge.net/ http://audacity.sourceforge.net/ > And another question: can alsa mix its playback and capture data? If > can, which tool does it use? > You have to tell it to do this through some external means. In a recent post, one suggestion was arecord -f <foo> | aplay arecord and aplay are in the utils package of alsa. Again, this can also be done with audacity. Two other solutions here are jack and pulseaudio. http://audacity.sourceforge.net/ http://jackaudio.org/ http://www.pulseaudio.org For all of the above functionality you can write your own routine to do them. Here is a link to the top level of the alsa api documentation. If you dig down, you should be able to find all alsa functionality needed. You can use alsa in combination with external libraries to get the results you want http://www.alsa-project.org/main/index.php/ALSA_Library_API > > Best Regards > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Owen Yan(hongliang) > > InfoMax Communication Co., Ltd. > NO. 5 Xinghai Rd.,Suzhou Industrial Park 215021 > Tel: 86-512-62580888-3455 > E-Mail: owen.yan@xxxxxxxxxxxxxx <mailto:owen.yan@xxxxxxxxxxxxxx> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
