[alsa-devel] ALSA DMIX support without MMAP ?

ANISH KUMAR anish.singh at samsung.com
Mon Jan 18 04:25:31 CET 2010

> Actually i am working on soc platform(android-S3C6410) and wanted to
> use DMIX and some good resampler for my software mixing instead of
> current software mixing and resampling in upper layer(Above
> alsa-lib).DMIX is working fine but this resampling is causing some
> jitter.During rate conversion it looks for
> libasound_module_rate_speexrate.so which i don't have so its using
> default one causing the jitter.
>>Have you considered using PulseAudio for this?

Mark thanks for the suggestion and i checked out PulseAudio for my requirements.I found out that i don't need all the things in PulseAudio 
a. I just need good resampling code.Can i just use just the resampler code of pulseaudio(mine is mobile enviroment)?
b. Just want a good mixer at ALSA-LIB level.As of now this is provided by android framework but i want this to be done by ALSA-LIB so that i
    can replace with some good mixer later on(if i find that some other mixer is good).DMIX is providing that but it's not that good.
c.Jaroslav suggested to use sox resamplers but for that to work i have to get the sox resampler code(proper license) and need to build it for my system and link it  
   with corresponding functions of ALSA-LIB so that they can call relevant functions for resampling.As i am working on mobile domain i think i need to do the   
    integration of sox resampler code with ALSA-LIB for that to work??
   Can i just use the integrated sox library(some .so i guess) and change the asound.conf for using that library??Will this work??
d. I saw some check-ins related to Scenario Manager.As of now scenario manager functionality is also given in Android(we open a differnet
    device and the corresponding hooks for changing the routes dynamically) but i think if it given in alsa-lib switching will be much faster and this 
    will increase the system performance.




More information about the Alsa-devel mailing list