Module: Vizcore::Audio::PortAudioFFI

Extended by:
PortAudioFFI
Included in:
PortAudioFFI
Defined in:
lib/vizcore/audio/portaudio_ffi.rb

Overview

PortAudio FFI bridge for microphone stream access and device discovery.

Defined Under Namespace

Classes: Stream

Constant Summary collapse

DEFAULT_CHANNELS =

Default mono channel count.

1
PA_NO_ERROR =

PortAudio no-error status code.

0
PA_FLOAT_32 =

PortAudio float sample format code.

0x0000_0001
PA_NO_FLAGS =

PortAudio stream flags.

0

Instance Method Summary collapse

Instance Method Details

#available? ⇒ Boolean

Returns true when PortAudio native library can be loaded.

Returns:

  • (Boolean) —

    true when PortAudio native library can be loaded



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# File 'lib/vizcore/audio/portaudio_ffi.rb', line 128

def available?
  !ffi_module.nil?
end

#close_stream(stream) ⇒ nil

Parameters:

Returns:

  • (nil) 


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# File 'lib/vizcore/audio/portaudio_ffi.rb', line 237

def close_stream(stream)
  stream&.close
  ffi_module&.Pa_Terminate
rescue StandardError
  nil
end

#input_devices ⇒ Array<Hash>

Returns available input device descriptors.

Returns:

  • (Array<Hash>) —

    available input device descriptors



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# File 'lib/vizcore/audio/portaudio_ffi.rb', line 133

def input_devices
  mod = ffi_module
  return [] unless mod
  return [] unless ok?(mod.Pa_Initialize)

  count = mod.Pa_GetDeviceCount
  return [] if count <= 0

  count.times.filter_map do |index|
    pointer = mod.Pa_GetDeviceInfo(index)
    next if pointer.null?

    info = mod::DeviceInfo.new(pointer)
    next unless info[:maxInputChannels].positive?

    {
      index: index,
      name: info[:name].read_string,
      max_input_channels: info[:maxInputChannels],
      default_sample_rate: info[:defaultSampleRate].to_f
    }
  end
ensure
  mod&.Pa_Terminate
end

#open_default_input_stream(sample_rate:, channels: DEFAULT_CHANNELS, frames_per_buffer: 1024) ⇒ Vizcore::Audio::PortAudioFFI::Stream?

Parameters:

  • sample_rate (Float)
  • channels (Integer) (defaults to: DEFAULT_CHANNELS)
  • frames_per_buffer (Integer) (defaults to: 1024)

Returns:



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# File 'lib/vizcore/audio/portaudio_ffi.rb', line 163

def open_default_input_stream(sample_rate:, channels: DEFAULT_CHANNELS, frames_per_buffer: 1024)
  mod = ffi_module
  return nil unless mod
  return nil unless ok?(mod.Pa_Initialize)

  stream_ptr_ptr = ffi::MemoryPointer.new(:pointer)

  result = mod.Pa_OpenDefaultStream(
    stream_ptr_ptr,
    Integer(channels),
    0,
    PA_FLOAT_32,
    Float(sample_rate),
    Integer(frames_per_buffer),
    nil,
    nil
  )
  return terminate_with_nil(mod) unless ok?(result)

  stream_pointer = stream_ptr_ptr.read_pointer
  return terminate_with_nil(mod) if stream_pointer.null?

  Stream.new(mod: mod, pointer: stream_pointer, channels: Integer(channels))
rescue StandardError
  mod&.Pa_Terminate
  nil
end

#open_input_stream(device:, sample_rate:, channels: DEFAULT_CHANNELS, frames_per_buffer: 1024) ⇒ Vizcore::Audio::PortAudioFFI::Stream?

Parameters:

  • device (String, Integer) —

    PortAudio device index or case-insensitive name fragment

  • sample_rate (Float)
  • channels (Integer) (defaults to: DEFAULT_CHANNELS)
  • frames_per_buffer (Integer) (defaults to: 1024)

Returns:



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# File 'lib/vizcore/audio/portaudio_ffi.rb', line 196

def open_input_stream(device:, sample_rate:, channels: DEFAULT_CHANNELS, frames_per_buffer: 1024)
  mod = ffi_module
  return nil unless mod
  return nil unless ok?(mod.Pa_Initialize)

  device_info = resolve_input_device(mod, device)
  return terminate_with_nil(mod) unless device_info

  device_index, info = device_info
  actual_channels = [Integer(channels), info[:maxInputChannels]].min
  input_params = mod::StreamParameters.new
  input_params[:device] = device_index
  input_params[:channelCount] = actual_channels
  input_params[:sampleFormat] = PA_FLOAT_32
  input_params[:suggestedLatency] = info[:defaultLowInputLatency].to_f
  input_params[:hostApiSpecificStreamInfo] = nil

  stream_ptr_ptr = ffi::MemoryPointer.new(:pointer)
  result = mod.Pa_OpenStream(
    stream_ptr_ptr,
    input_params.to_ptr,
    nil,
    Float(sample_rate),
    Integer(frames_per_buffer),
    PA_NO_FLAGS,
    nil,
    nil
  )
  return terminate_with_nil(mod) unless ok?(result)

  stream_pointer = stream_ptr_ptr.read_pointer
  return terminate_with_nil(mod) if stream_pointer.null?

  Stream.new(mod: mod, pointer: stream_pointer, channels: actual_channels)
rescue StandardError
  mod&.Pa_Terminate
  nil
end