[nas] Re: help with using sox with nas-piping sound

[Tobias Diedrich]

sibusiso xolo wrote:

> a)  future extensions of libaudiooss be made that fragment size and number be
> set externally rather than recompiling the program

A patch for that should be easy, I'll probably make one later...

> b) the use of  sox (or another sound conversin program)  to work with audio 
> input from the  tv/radio card

That is not a problem with sox but with audio routing. When you record
audio, you have to say the soundcard from which source you want to
record. Some support recording from multiple source (which get mixed
before recording), other only support recording from one source at a
time. The default is usally microphone input.
Your first step should be to determine to which source your TV card is
connected. My Hauppauge WinTV has an external lineout connector which is
connected to the linein on my Soundcard, so I have to set the recording
source to linein (With aumix you can do this with "aumix -lR").
It may be connected internally and/or to another input, e.g. aux, cd, line2.
If you don't have an external cable going from your TV card to your
soundcard, start xawtv and a mixer program and turn volume knobs (except
the master one of course) to see which one changes your TV cards volume.
Usually your mixing program allows you to change the recording source in
interactive mode too. With aumix you do this with spacebar. With kmix
this is done by clicking the red led below the slider.

> c) ability to define multiple  audioservers  (on different ports)  to enable 
> broadcasting

While would be basically possible it has some problems which are not too
easy to solve. This would probably best be a standalone app that handles
this. To sync the soundcards you have to dynamically resample to a
different rate for each server and there might still be different
delays.

> d) 44.1 kHz CD quality input to nas server

That one should already work. As I said you probably misunderstood the
comment in /etc/nas/nasd.conf.
BTW how about changing the default to wordsize 16 numchans 2 ?

> >LD_PRELOAD= sox -w -s -c 2 -r 44100 -t ossdsp /dev/dsp -t raw - |
> > LD_PRELOAD=libaudiooss.so sox -t raw -w -s -c 2 -r 44100 - -t ossdsp
> > /dev/dsp
>
> does not work on the machines I have tried.  I have varied sound quality etc  
> and I have recording  enabled on the line-input of the sound mixer of the 
> client.  I expected the  execution of sox to hang in the terminal whilst it 
> pipes sound but it  returns to command prompt  soon after  command execution.   
> All  suggestion welcomed.

I would not expect it to return immediately (I would not use the term
"hang" here). Does it give you some error message ?

-- 
Tobias								PGP: 0x9AC7E0BC
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