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Changing volume in Linux with Perl?

by PipTigger (Hermit)
on Jan 16, 2001 at 06:06 UTC ( #52132=perlquestion: print w/replies, xml ) Need Help??

PipTigger has asked for the wisdom of the Perl Monks concerning the following question:

Hello, oh ye who possess magical wisdom,
I'm trying to manipulate sound volume (both main && pcm) from a script. Right now I've got aumix installed so just doing system("aumix -v$NewVolum") werks for me but is not a good solution. I've STFC (Serched The Fscking CPAN) && only found a wrapper for mixing .wav files together. How can I cleanly manipulate /dev/mixer in order to change volumes && stuff? The source to aumix doesn't give me a good clue of how I might mimic in Perl. Thanks muchly for any assistance you might be able to provide. TTFN.

p.s. Initiate Nail Removal Immediately!

Replies are listed 'Best First'.
Re: Changing volume in Linux with Perl?
by eg (Friar) on Jan 16, 2001 at 06:47 UTC
      Actually I have in fact read almost everything at that linq before too... the problem is that the method described there is basically what the aumix C-code I already have does. Is there an equivalent to 'sys/ioctl.h' in Perl? Is there a way to manipulate /dev/mixer properly without compiling C? If not, aumix will suffice but it'd be nice to do it right in Perl if possible. Maybe it'd make a great CPAN module too. We'll see. Thanks. TTFN.

      p.s. I don't need your authority!
        Have a look at ioctl for a way to roll your own in perl. I agree that this would make a handy CPAN module when you get it working. Good luck!

Re: Changing volume in Linux with Perl?
by PipTigger (Hermit) on Jan 16, 2001 at 16:15 UTC
    I've tried hard to get ioctl && all the other .ph files to werk. I had to run h2ph on like 7 different .h files to fulfill all the embedded require's but I've tried tons of stuff for the past hour to tweak my new /usr/local/lib/site_perl/i386-linux/linux/ file so that it'd let my little script run to no avail. My little test is:
    #!/usr/bin/perl -w require ''; require 'linux/'; my $data = 0; open MIXR, "</dev/mixer" || die "Can't open mixer!\n"; ioctl(MIXR, &MIXER_READ(0), $data) || die "Can't ioctl!\n"; close MIXR; print "data: $data\n";
    This results in:

    Use of uninitialized value at (eval 621) line 1.
    Can't ioctl!

    && the eval ending on that line looks like another normal one:
    eval 'sub SEQ_PITCHBEND { local($dev, $voice, $value) = @_; eval q( &SEQ_V2_X_CONTROL($dev, $voice, &CTRL_PITCH_BENDER, $ +value) ); }' unless defined(&SEQ_PITCHBEND);
    If you can possibly point me in a better direction, I'd really appreciate it. I've been pounding my head against this for a long time && can't seem to go anywhere with this. I'm feeling really surprised at how difficult this seems to be in Perl! Maybe it's appropriate since it's one of the "hard/possible" things but it seemed like it should be "easy/easy". Anyways, I'm probably just gonna cave in && use C if I can't get Perl to do it within the next day or so. I really wanted to be competent enough to get this to werk on my own but I'm left to conclude that I'm really not experienced enough with Perl || Linux to do this alone yet. Thanks for any help or encouragement you can offer. I'm feeling kinda down (I thinq the caffeine is wearing off). TTFN.

    p.s. Mr., would you please help my pony?

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