Class: ALSA::PCM::Stream

Inherits:
Object
  • Object
show all
Defined in:
lib/alsa/pcm/stream.rb

Direct Known Subclasses

Capture, Playback

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#handle ⇒ Object

Returns the value of attribute handle.



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# File 'lib/alsa/pcm/stream.rb', line 4

def handle
  @handle
end

Class Method Details

.open(device = "default", hardware_attributes = {}, &block) ⇒ Object 



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# File 'lib/alsa/pcm/stream.rb', line 6

def self.open(device = "default", hardware_attributes = {}, &block)
  new.open(device, hardware_attributes, &block)
end

Instance Method Details

#change_hardware_parameters ⇒ Object 



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# File 'lib/alsa/pcm/stream.rb', line 28

def change_hardware_parameters
  hw_params = ALSA::PCM::HwParameters.new(self).default_for_device

  begin
    yield hw_params

    ALSA::try_to "set hw parameters" do
      ALSA::PCM::Native::hw_params self.handle, hw_params.handle
    end
  ensure
    hw_params.free
  end
end

#check_handle! ⇒ Object 



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# File 'lib/alsa/pcm/stream.rb', line 64

def check_handle!
  raise "Stream isn't opened" unless opened?
end

#close ⇒ Object 



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# File 'lib/alsa/pcm/stream.rb', line 68

def close
  ALSA::try_to "close audio device" do
    ALSA::PCM::Native::close self.handle
    self.handle = nil
  end
end

#hardware_parameters ⇒ Object Also known as: hw_params 



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# File 'lib/alsa/pcm/stream.rb', line 42

def hardware_parameters
  ALSA::PCM::HwParameters.new(self).current_for_device
end

#hardware_parameters=(attributes = {}) ⇒ Object 



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# File 'lib/alsa/pcm/stream.rb', line 47

def hardware_parameters=(attributes= {})
  attributes = { 
    :access => :rw_interleaved, 
    :channels => 2, 
    :sample_format => :s16_le, 
    :sample_rate => 44100 
  }.update(attributes)

  change_hardware_parameters do |hw_params|
    hw_params.update_attributes(attributes)
  end
end

#open(device = "default", hardware_attributes = {}, &block) ⇒ Object 



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# File 'lib/alsa/pcm/stream.rb', line 10

def open(device = "default", hardware_attributes = {}, &block)
  handle_pointer = FFI::MemoryPointer.new :pointer
  ALSA::try_to "open audio device #{device}" do
    ALSA::PCM::Native::open handle_pointer, device, native_constant, ALSA::PCM::Native::BLOCK
  end
  self.handle = handle_pointer.read_pointer

  self.hardware_parameters = hardware_attributes

  if block_given?
    begin
      yield self 
    ensure
      self.close
    end
  end
end

#opened? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/alsa/pcm/stream.rb', line 60

def opened?
  not self.handle.nil?
end