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¶
Overview ¶
Package audio provides audio players.
The stream format must be 16-bit little endian and 2 channels. The format is as follows:
[data] = [sample 1] [sample 2] [sample 3] ... [sample *] = [channel 1] ... [channel *] = [byte 1] [byte 2] ...
An audio context (audio.Context object) has a sample rate you can specify and all streams you want to play must have the same sample rate. However, decoders in e.g. audio/mp3 package adjust sample rate automatically, and you don't have to care about it as long as you use those decoders.
An audio context can generate 'players' (audio.Player objects), and you can play sound by calling Play function of players. When multiple players play, mixing is automatically done. Note that too many players may cause distortion.
For the simplest example to play sound, see wav package in the examples.
Index ¶
- type Context
- type InfiniteLoop
- type Player
- func (p *Player) Close() error
- func (p *Player) Current() time.Duration
- func (p *Player) IsPlaying() bool
- func (p *Player) Pause() error
- func (p *Player) Play() error
- func (p *Player) Rewind() error
- func (p *Player) Seek(offset time.Duration) error
- func (p *Player) SetVolume(volume float64)
- func (p *Player) Volume() float64
- type ReadSeekCloser
Constants ¶
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Variables ¶
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Functions ¶
This section is empty.
Types ¶
type Context ¶
type Context struct {
// contains filtered or unexported fields
}
A Context represents a current state of audio.
At most one Context object can exist in one process. This means only one constant sample rate is valid in your one application.
For a typical usage example, see examples/wav/main.go.
func CurrentContext ¶ added in v1.6.0
func CurrentContext() *Context
CurrentContext returns the current context or nil if there is no context.
func NewContext ¶
NewContext creates a new audio context with the given sample rate.
The sample rate is also used for decoding MP3 with audio/mp3 package or other formats as the target sample rate.
sampleRate should be 44100 or 48000. Other values might not work. For example, 22050 causes error on Safari when decoding MP3.
Error returned by NewContext is always nil as of 1.5.0-alpha.
NewContext panics when an audio context is already created.
type InfiniteLoop ¶ added in v1.5.0
type InfiniteLoop struct {
// contains filtered or unexported fields
}
InfiniteLoop represents a looped stream which never ends.
func NewInfiniteLoop ¶ added in v1.5.0
func NewInfiniteLoop(src ReadSeekCloser, length int64) *InfiniteLoop
NewInfiniteLoop creates a new infinite loop stream with a source stream and length in bytes.
func NewInfiniteLoopWithIntro ¶ added in v1.8.0
func NewInfiniteLoopWithIntro(src ReadSeekCloser, introLength int64, loopLength int64) *InfiniteLoop
NewInfiniteLoopWithIntro creates a new infinite loop stream with an intro part. NewInfiniteLoopWithIntro accepts a source stream src, introLength in bytes and loopLength in bytes.
func (*InfiniteLoop) Close ¶ added in v1.5.0
func (l *InfiniteLoop) Close() error
Close is implementation of ReadSeekCloser's Close.
type Player ¶
type Player struct {
// contains filtered or unexported fields
}
Player is an audio player which has one stream.
Even when all references to a Player object is gone, the object is not GCed until the player finishes playing. This means that if a Player plays an infinite stream, the object is never GCed unless Close is called.
func NewPlayer ¶
func NewPlayer(context *Context, src io.ReadCloser) (*Player, error)
NewPlayer creates a new player with the given stream.
src's format must be linear PCM (16bits little endian, 2 channel stereo) without a header (e.g. RIFF header). The sample rate must be same as that of the audio context.
The player is seekable when src is io.Seeker. Attempt to seek the player that is not io.Seeker causes panic.
Note that the given src can't be shared with other Player objects.
NewPlayer tries to call Seek of src to get the current position. NewPlayer returns error when the Seek returns error.
NewPlayer takes the ownership of src. Player's Close calls src's Close.
func NewPlayerFromBytes ¶ added in v1.4.0
NewPlayerFromBytes creates a new player with the given bytes.
As opposed to NewPlayer, you don't have to care if src is already used by another player or not. src can be shared by multiple players.
The format of src should be same as noted at NewPlayer.
NewPlayerFromBytes's error is always nil as of 1.5.0-alpha.
func (*Player) Close ¶
Close closes the stream.
When closing, the stream owned by the player will also be closed by calling its Close. This means that the source stream passed via NewPlayer will also be closed.
Close returns error when closing the source returns error.
func (*Player) Rewind ¶
Rewind rewinds the current position to the start.
The passed source to NewPlayer must be io.Seeker, or Rewind panics.
Rewind returns error when seeking the source stream returns error.
func (*Player) Seek ¶
Seek seeks the position with the given offset.
The passed source to NewPlayer must be io.Seeker, or Seek panics.
Seek returns error when seeking the source stream returns error.
type ReadSeekCloser ¶
type ReadSeekCloser interface {
io.ReadSeeker
io.Closer
}
ReadSeekCloser is an io.ReadSeeker and io.Closer.
func BytesReadSeekCloser ¶ added in v1.5.0
func BytesReadSeekCloser(b []byte) ReadSeekCloser
BytesReadSeekCloser creates ReadSeekCloser from bytes.
Source Files
Directories
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| Path | Synopsis |
|---|---|
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internal
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Package mp3 provides MP3 decoder.
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Package mp3 provides MP3 decoder. |
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Package vorbis provides Ogg/Vorbis decoder.
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Package vorbis provides Ogg/Vorbis decoder. |
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Package wav provides WAV (RIFF) decoder.
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Package wav provides WAV (RIFF) decoder. |