The following code works:


    require 'sdl'
    SDL.init(SDL::INIT_AUDIO)
    mixer = SDL::Mixer.open(22050, SDL::Mixer::DEFAULT_FORMAT, 1, 1024)
    wave = SDL::Mixer::Wave.load("sample.wav")
    SDL::Mixer.play_channel(0, wave, 0)
    while SDL::Mixer::play?(0)
      sleep 1
    end


But the following code fails:


    require 'sdl'
    SDL.init(SDL::INIT_AUDIO)
    mixer = SDL::Mixer.open(22050, SDL::Mixer::DEFAULT_FORMAT, 1, 1024)
    stream = File.open("sample.wav")
    wave = SDL::Mixer::Wave.load_from_io(stream)
    SDL::Mixer.play_channel(0, wave, 0)
    while SDL::Mixer::play?(0)
      sleep 1
    end


Output:


    $ ruby soundtest.rb 
    soundtest.rb:6:in `load_from_io': cannot seek backward (SDL::Error)
	    from soundtest.rb:6

Date: 2009-11-15 15:15
Sender: Ippei Ohbayashi

How about the version of your Ruby/SDL? Newest
version of Ruby/SDL doesn't have such error.