On 12-06-08 16:14, Florian Winter wrote: > I have some more questions: > Is there a way to find out which soundcards support hardware mixing (and > have support for it implemented in their corresponding ALSA drivers)?
Not all that easily from the code. The ALSA soundcard matrix at: http://www.alsa-project.org/main/index.php/Matrix:Main might be the best source. You'll have to compensate for not everything on there being accurate; for the TerraTec page I know that where HWMIX is listed, it's accurate: http://www.alsa-project.org/main/index.php/Matrix:Vendor-Terratec Those are older chips though. > Is it safe to assume that ALSA will not use dmix if the sound card > (and the ALSA driver for it) supports hardware mixing? Yes. And as such, checking the files under /usr/share/alsa/cards to note which ones DO setup dmix and subtracing those from the complete set would be another way of answering the above question. If a card uses dmix by default, it's through the mechanism you see in those files (for example, see ENS1370.conf for a card that uses dmix). As an aside -- note that "hardware" mixing might not be any better than software mixing. One obvious way of implementing it inside a chip is as much upsampling to a common internal rate as it is software and in hardware you have even fewer resources meaning it might very well be that you'd in fact be better of with dmix than without. A while ago I for example noticed that an 8000 Hz file played back by a TerraTec DMX (snd-es1968) sounded every bit as crummy as that same file at 48000 after externally upsampling it (with sox) through bad quality linear upsampling. A good quality upsampling to 48000 got me the same sound from the DMX as a different, non-mixing, card produced while playing back the original file so the DMX is using bad upsampling, at least for 8000 Hz sources. Rene. ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
