prelude

type IO struct {
	// common
	Address  string
	Format   string
	Index    uint64
	Stream   uint64
	Language string
	Type     string
	Codec    string
	Coder    string
	Bitrate  float64 // kbps
	Duration float64 // sec

	// video
	FPS    float64
	Pixfmt string
	Width  uint64
	Height uint64

	// audio
	Sampling uint64 // Hz
	Layout   string
	Channels uint64
}