Re: [Discuss-gnuradio] Audio spectrum inversion - easy & fun

[Chuck Swiger]

At 06:21 PM 10/3/2004 +0930, you wrote:

> Does linux allow you to open the same device twice? Both calls to 
> audio_source
> and audio_sink open the same device namely /dev/dsp and hence would return
> two file handles:
>
>
> Running the above demo program with GnuRadio on a NetBSD system will return a
> "device busy" signal as one would expect. Am I missing something here? What
> is the secret? :)
>
> Also, If I'm not mistaken, the code demonstrated contains a couple of typos:


Hi Berndt - yes there were two typos, the dangers of not having 
cut-and-paste working.

I cannot speak to the sound card issue on NetBSD - it does work on Linux 
(RedHat
Fedora Core 2) with the sound device built into an Asus A7V motherboard. Is 
your
sound card full duplex? Many are not, and only allow opening for input or 
output only,
but not both.

You could always break the script up into two parts - One records the audio 
stream
to a disk file, and the other plays the disk file back, with the vector 
mixing in one or the
other.

In the first part your 'out' would be something like
        out = gr.file_sink (gr.sizeof_float, "filename")

and in the second your 'src' would be like
        src = gr.file_source (gr.sizeof_float, "filename", X )   //   X=1 
repeat,  X=0 play one time


Good luck!

Chuck