On Friday 15 May 2009, Grant wrote: > > So how come that you don't get 'em with mpd?! > > In mpd I specify oss instead of alsa. If I specify alsa and involve > dmix, I get static in mpd too.
you say OSS... but was that the "real" oss (does it still exist for modern kernels/hardware?!) or was it just the ALSA oss emulation? If it's the latter (as usually is on modern systems), then its just the input interface that changes, you're goin' trough ALSA anyway. On the other end, if it really was the former (real OSS stack), then likely you have a problem with mixed+conflicting drivers... ALSA and "real" OSS can NOT coexist on a system. > > again, I believe that your problem is completely unrelated to the > > resampling algorithm used. [...] > Well, there is a blog post under "A little hint for hda ALSA users" which > says: > > "if you own an hda-based soundcard and you head crackling sound while > playing mp3s or similar, the problem is probably due to the bad > samplerate conversion from 44100 to 48000." Sorry, I won't believe that. AFAIK ALSA is a "layered" stack where higher level "functions" such as dmix and resampling are implemented in their own layer which is "sitting on top" of the lover level ones (such as hardware drivers). Obviously the higher level functions are not implemented within the hardware-specific low level drivers and -AFAIK- they remain the same whatever low level driver is in use. So how/why something like any given ALSA resampling algorithm could work differently when paired with different hardware? BTW, on my HTPC (which by chance is the machine I'm on now) I have an Intel DP35DP. That have an ICH9 HD Audio Controller. Which I use when playing to the HDTV own speakers (rather than the HiFi system, for which as said I use a Juli@). Needless to say, it works perfectly with any resampling algorithm, using either analog or digital outputs at whatever sampling rate. I also have an old laptop with ICH4, my office desktop which have ICH5, another laptop with ICH7, ... not counting the large number of other Linux machines I manage at work. I believe I can say to have seen quite some different hardware/software combinations. In some 10+ years of Linux system management I have had troubles with unsupported hardware, incomplete and/or broken drivers, etc, but have never experienced "static" noise or otherwise broken audio due to poor resampling using the default ALSA config. On the other end, your referenced blog says explicitely: > http://blog.flameeyes.eu/tag/alsa/page/2 > > "although I admit I haven’t tried it first hand, as I don’t have any > hda-based soundcard beside the laptop" who should I believe? my own experience or his 2nd hand rumors? ;-) > > Only once you've got the default config to work properly you may start > > experimenting with more sophisticated options. > > That sounds good, but what else can I try? what I'd do as a first step is trying to get your own distribution / installation / customizations out of the mix. So get some proven Live CD/DVD (NOT Gentoo-based!) and try with those. I'd try with Ubuntu 9.04, then perhaps Mandriva 2009, good old Knoppix, etc. Try to get systems with several different kernel/alsa version combinations, and report what happen... maybe it'll turn out that you'll have to file a bug report. Ciao, Paolo. -- Skype: Paolo.Saggese http://borex.lngs.infn.it/saggese You can still escape from the GATES of hell: Use Linux! -- Ciao, Paolo. -- Skype: Paolo.Saggese http://borex.lngs.infn.it/saggese You can still escape from the GATES of hell: Use Linux! ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
