On Tue, 20 Nov 2007, stan wrote: > Vladimir Mosgalin wrote: >> Hi paul blakeley! >> >> On 2007.11.20 at 12:26:29 +0000, paul blakeley wrote next: >> >> >>> Can someone please explain the differences between these? What impact >>> they have on the application? >>> >> >> plughw supports much more sample formats / channel configurations >> than underlying hardware supports natively, and performs conversion if >> needed. hw performs no conversion, but supports less configuration, >> sometimes only very obscure ones, but when used you can rest assured >> that no conversion takes place. >> >> Mostly you'd want these conversions to take place, like mono->stereo >> conversion or S16LE->S32LE conversion etc (all depending on your >> hardware)
Mostly this is true, except for sample rate conversion. The sample rate conversion routines are primative and add distortion and noise to the signal, and you, in general, do not want to do that. Almost all of the other conversions do not destroy the signal while converting, so are best left to the plughw to handle, agreed. The propensity of some card manufacturers to not support rates like 44100, the ubiquitous recorded rate, makes it difficult of course. >> >> ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
