Re: Rate Conversion

[Kris Modrak <u9514439@anu.edu.au>]

Paul Davis wrote:
> 
> >> You don't need to do this. Use the 'plughw' device which should do all
> >> conversions from you.
> >
> >I am a little confused about your advice. I am not sure how to access
> >the 'plughw' device from my application.
> 
>      snd_pcm_open (&handle, "plughw:N,M", ...)
> 
> where N and M are the card number and subdevice number. Preferably,
> this is a string supplied by the user, not hard coded into the application.
> 
> >I am not sure of how I should be setting up my PCM devices. How do I
> >tell them to convert, say, 8kHz audio data to 44.1kHz audio data so my
> >hardware can play it at the correct speed?
> 
> just as in the few token API examples. using
> snd_pcm_hw_params_*(). there is no difference setting the parameters
> no matter what "type" of PCM device you are using.

If use the virtual plughw:0,0 device and set the rate to 8kHz, at what
rate is my actual hardware device set to? Where are these settings made
and how are they decided?

Do I need to, or is it possible to, tell my soundcard to operate at
44.1kHz?

Kris Modrak


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