codec

Documentation

Index

• Constants
• Variables
• func RegisterCodec(name string, magic, extensions []string, decode func(Reader) (Songs, error), ...)
• type ID
  • func Int(i int) ID
  • func Int64(i int64) ID
  • func NewID(s ...string) ID
  • func (i ID) Pop() (string, ID)
  • func (i ID) Push(s string) ID
  • func (i ID) Top() string
• type Reader
  • func (rf Reader) Metadata(ft tag.FileType) (*SongInfo, tag.Metadata, []byte, error)
• type Song
  • func ByExtensionID(path string, id ID, rf Reader) (Song, error)
• type SongInfo
• type Songs
  • func ByExtension(path string, rf Reader) (Songs, string, error)
  • func Decode(rf Reader) (Songs, string, error)

Constants

const IdSep = "\n"

Variables

var ErrFormat = errors.New("codec: unknown format")

ErrFormat indicates that decoding encountered an unknown format.

Functions

func RegisterCodec

func RegisterCodec(name string, magic, extensions []string, decode func(Reader) (Songs, error), get func(Reader, ID) (Song, error))

RegisterCodec registers an audio codec for use by Decode. Name is the name of the format, like "nsf" or "wav". Magic is the magic prefix that identifies the codec's encoding. The magic string can contain "?" wildcards that each match any one byte. Decode is the function that decodes the encoded codec.

Types

type ID

type ID string

const None ID = ""

func Int

func Int(i int) ID

func Int64

func Int64(i int64) ID

func NewID

func NewID(s ...string) ID

func (ID) Pop

func (i ID) Pop() (string, ID)

func (ID) Push

func (i ID) Push(s string) ID

func (ID) Top

func (i ID) Top() string

type Reader

type Reader func() (io.ReadCloser, int64, error)

Reader returns a file reader and the file size in bytes (or 0 if streamed or unknown).

func (Reader) Metadata

func (rf Reader) Metadata(ft tag.FileType) (*SongInfo, tag.Metadata, []byte, error)

type Song

type Song interface {
	// Info returns information about a song.
	Info() (SongInfo, error)
	// Init is called before the first call to Play(). It should prepare resources
	// needed for Play().
	Init() (sampleRate, channels int, err error)
	// Play returns the next n samples. Return < n to indicate end of song or 0
	// to indicate EOF, neither of which should return an error. If < n samples
	// are returned, Play will not be invoked again.
	Play(n int) ([]float32, error)
	// Close releases resources used by the current file.
	Close()
}

func ByExtensionID

func ByExtensionID(path string, id ID, rf Reader) (Song, error)

type SongInfo

type SongInfo struct {
	Time     time.Duration
	Artist   string
	Title    string
	Album    string
	Track    float64
	ImageURL string `json:",omitempty"`
}

type Songs

type Songs map[ID]Song

func ByExtension

func ByExtension(path string, rf Reader) (Songs, string, error)

func Decode

func Decode(rf Reader) (Songs, string, error)

Decode decodes audio that has been encoded in a registered codec. The string returned is the format name used during format registration. Format registration is typically done by the init method of the codec- specific package.