On Thu, Jun 12, 2008 at 6:05 PM, Roman Haefeli <reduzierer@xxxxxxxx> wrote: <SNIP> > > are you saying, that it is simply not possible to run jackd over an alsa > plugin, that does resampling or mixing? if so, does that mean, that Yes, I am saying that. Jack communicates directly with the hardware. Jack gets its sample clock FROM the hardware you interface it to. If your hardware only runs at 48K then that is the only clock available to Jack and therefore the only frequency it can run at. > jackd is kind of a special alsa client? I suppose that's one way of looking at it. > why are alsa clients different? Well, Jack is different because it specifically manages all the buffers to and from the hardware, as well as allowing inter-application communication without any worries about sample rates. To and from the hardware I believe the Jack server looks like a well designed Alsa device. Every proper Jack client is then designed to receive and provide buffers of data at the rate Jack runs. Therefore, strictly speaking, Jack clients don't really need to know what sample rate they are running at. They all just move buffers of audio data and Jack takes care of the rate and the rate is the clock speed of the audio card. > when alsaplayer is able to use -d plug:dmix, why isn't jackd? i seem to > lack fundamental understanding of what alsa is about. No, you're doing OK, but it is a bit confusing if you haven't figured it out yet. Alsaplayer, as an alsa application, plays it's CD or sound file and sends it's data to plug:dmix which then is free to resample, mix audio, etc. dmix then sends the audio to the sound card's alsa driver. Jack is between what you think of as dmix (which is software) and the Alsa-driver/sound card combination. All of the audio goes in and out of the jackd daemon. Jack then routes the audio, copies the audio, and sends the audio where it needs to go. If 3 apps want the same audio then Jack can sent it to all 3. If three apps want to send audio to the sound card then Jack can mix the audio together into a single stream. Jack sits in between all the Jack apps and the card's alsa driver. Jack then sends the audio to the alsa driver which gets it to the card. Technically, I think you're looking for a Jack aware resampling plugin. you would send your 44.1K sound file to that device and then let it resample it to the Jack sample rate - 48K in your case. I'm not sure what you should get to do this but almost certainly there is one somewhere in the LADSPA library. Hope this helps, Mark > > roman > > > > > ___________________________________________________________ > Telefonate ohne weitere Kosten vom PC zum PC: http://messenger.yahoo.de > > ------------------------------------------------------------------------- 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@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
