output

type NewOutputOptions struct {
	// Backend is the audio backend to use (also, pulseaudio, etc).
	Backend string

	// Reader provides data for the output device.
	//
	// The format of data is as follows:
	//
	//	[data]      = [sample 1] [sample 2] [sample 3] ...
	//	[sample *]  = [channel 1] [channel 2] ...
	//	[channel *] = [byte 1] [byte 2] ...
	//
	// Byte ordering is little endian.
	Reader librespot.Float32Reader

	// SampleRate specifies the number of samples that should be played during one second.
	// Usual numbers are 44100 or 48000. One context has only one sample rate. You cannot play multiple audio
	// sources with different sample rates at the same time.
	SampleRate int

	// ChannelCount specifies the number of channels. One channel is mono playback. Two
	// channels are stereo playback. No other values are supported.
	ChannelCount int

	// Device specifies the audio device name.
	//
	// This feature is support only for the alsa backend.
	Device string

	// Mixer specifies the audio mixer name.
	//
	// This feature is support only for the alsa backend.
	Mixer string
	// Control specifies the mixer control name
	//
	// This only works in combination with Mixer
	Control string

	// BufferTimeMicro is the buffer time in microseconds.
	//
	// This is only supported on the alsa backend.
	BufferTimeMicro int

	// PeriodCount is the number of periods to request.
	//
	// This is only supported on the alsa backend.
	PeriodCount int

	// InitialVolume specifies the initial output volume.
	//
	// This is only supported on the alsa backend. The PulseAudio backend uses
	// the PulseAudio default volume.
	InitialVolume float32

	// ExternalVolume specifies, if the volume is controlled outside of the app.
	//
	// This is only supported on the alsa backend. The PulseAudio backend always
	// uses external volume.
	ExternalVolume bool

	// VolumeUpdate is a channel on which volume updates will be sent back to
	// Spotify. All updates come through this channel, including those sent by
	// Spotify.
	// This must be a buffered channel.
	VolumeUpdate chan float32
}

type Output interface {
	// Pause pauses the output.
	Pause() error

	// Resume resumes the output.
	Resume() error

	// Drop empties the audio buffer without waiting.
	Drop() error

	// DelayMs returns the output device delay in milliseconds.
	DelayMs() (int64, error)

	// SetVolume sets the volume (0-1).
	SetVolume(vol float32)

	// Error returns the error that stopped the device (if any).
	Error() <-chan error

	// Close closes the output.
	Close() error
}