http://qs321.pair.com?node_id=587494

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

Given how slow XMMS::Remote responds on my laptop (not sure why), I've been thinking of ditching it in favor of SDL::Music;

So I have it a whirl like so... 
#!/usr/bin/perl
use strict;
use warnings;
use SDL;
use SDL::Mixer;
use SDL::Music;
my $mixer = new SDL::Mixer(-frequency=>44100, 
               -channels=>2, 
               -size=>1024);
  
my $mp3 = new SDL::Music('./test.mp3');  

$mixer->play_channel(0, $mp3, 0);

[download]
Which dies with "open /dev/sequencer: No such device".

Why is it looking at /dev/sequencer and how do I change it?

I'm running Debian etch (alsa with oss support). I've looked through the src (SDL 2.1.3) and I can't figure for the life of me how to set it. The one audio example that comes with it (test/loopwave.pl) doesn't use SDL::Mixer, it uses SDL::NewAudioSpec to set up the audio.

Any pointers would be appreciated.

-Lee
"To be civilized is to deny one's nature."

Replies are listed 'Best First'.
Re: SDL::Mixer - How to specify the device?
by zentara (Archbishop) on Dec 03, 2006 at 13:26 UTC
    Just helping you troubleshoot, but your script dosn't play on my linux box with the latest kernel and alsa. So I'm not sure, but there are 2 possible errors I see.

    1. Try this script, it uses play_music instead of play_channel, and puts a loop at the end to keep the script from exiting prematurely. 

    #!/usr/bin/perl
use strict;
use warnings;
use SDL;
use SDL::Mixer;
use SDL::Music;


my $mixer = SDL::Mixer->new(
    -frequency => MIX_DEFAULT_FREQUENCY, # 22050
    -format    => MIX_DEFAULT_FORMAT,    # AUDIO_S16
    -channels  => MIX_DEFAULT_CHANNELS,  # 8
    -size      => 1024    #higher numbers give sloppy reponse
                          #as buffers continue to empty
);
# provides 8 channels of
# 16 bit audio at 22050 Hz. and a single channel of music.

#background can be mp3,ogg or wav (mp3 needs smpeg libs)
my $mp3  = new SDL::Music('1bb.mp3');

$mixer->music_volume(MIX_MAX_VOLUME); #128

$mixer->play_music( $mp3, 100 ); 

my $done = 0;
while (! $done && ( SDL::GetAudioStatus() 
       == SDL_AUDIO_PLAYING())) {SDL::Delay(1); }

    [download]

    2. Look for /dev/sequencer in /dev. On my alsa setup there is a link to /dev/sound/sequencer, which is what alsa sets up. Maybe you are missing the link?

    See Tk Game Sound demo

    I'm not really a human, but I play one on earth. Cogito ergo sum a bum
[reply]
[d/l]
      A kick in the right direction.

      My example wasn't dying, it was just a warning. It just was exiting so quick as I wasn't delaying, I didn't even hear a pop on the speaker.

      Having said that, play_music is what I needed, as play_channel screetches for some seconds and then SEGFAULTs.

      I do have /dev/sequencer , maybe a driver problem, but I don't listen to MIDI so I'm not too concerned.

      Thanks.

      -Lee
      "To be civilized is to deny one's nature."
[reply]
Re: SDL::Mixer - How to specify the device?
by Anonymous Monk on Dec 03, 2006 at 14:06 UTC
    Try 
    die "Could not initialize SDL: ", SDL::GetError()
    if ( 0 > SDL::Init(SDL_INIT_AUDIO()));

    [download]
    See http://libsdl.org/
[reply]
[d/l]
      Still get the warning about sequencer, but it doesn't die.

      -Lee
      "To be civilized is to deny one's nature."
[reply]
Re: SDL::Mixer - How to specify the device?
by shotgunefx (Parson) on Dec 04, 2006 at 12:17 UTC
    A little update, so far so good on switching to SDL::Music.

    Hit one snag, Perl_SDL doesn't expose any way to pan the mixer. On the plus side, a little googling, some minor additions the XS and panning works. (Hopefully, it gets patched in to the distribution )

    -Lee
    "To be civilized is to deny one's nature."
[reply]

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