opus

README

opus-go

Go bindings for opus. Modern audio compression for the internet.

Why opus-go

The purpose of opus-go is easing the adoption of opus codec library. Using Go, with just a few lines of code you can implement an application that encode/decode data easy.

Is this a new implementation of opus?

No! We are just exposing the great work done by the research organization of Xiph as a golang library. All the functionality and implementation still resides in the official opus project.

Features supported

• Decode Opus to PCM
• Encode PCM to Opus

Usage

Decode AAC frame to PCM

package main

import (
	"fmt"

	opus "github.com/qrtc/opus-go"
)

func main() {
	decoder, err := opus.CreateOpusDecoder(&opus.OpusDecoderConfig{
		SampleRate:  48000,
		MaxChannels: 2,
	})
	if err != nil {
		fmt.Println(err)
		return
	}
	defer func() {
		decoder.Close()
	}()

	inBuf := []byte{
		// Opus frame
	}
	outBuf := make([]byte, 4096)

	n, err := decoder.Decode(inBuf, outBuf)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(outBuf[0:n])
}

Enode PCM to AAC

package main

import (
	"fmt"

	opus "github.com/qrtc/opus-go"
)

func main() {
	encoder, err := opus.CreateOpusEncoder(&opus.OpusEncoderConfig{
		SampleRate:  48000,
		MaxChannels: 2,
		Application: opus.AppVoIP,
	})
	if err != nil {
		fmt.Println(err)
		return
	}
	defer func() {
		encoder.Close()
	}()

	inBuf := []byte{
		// PCM bytes
	}
	outBuf := make([]byte, 4096)

	n, err := encoder.Encode(inBuf, outBuf)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(outBuf[0:n])
}

Dependencies

• opus

Documentation

Index

• Constants
• type Application
• type BandwidthType
• type FrameSizeType
• type OpusDecoder
  • func CreateOpusDecoder(config *OpusDecoderConfig) (dec *OpusDecoder, err error)
  • func (dec *OpusDecoder) Close() error
  • func (dec *OpusDecoder) Decode(in, out []byte) (int, error)
• type OpusDecoderConfig
• type OpusEncoder
  • func CreateOpusEncoder(config *OpusEncoderConfig) (enc *OpusEncoder, err error)
  • func (enc *OpusEncoder) Close() error
  • func (enc *OpusEncoder) Encode(in, out []byte) (int, error)
  • func (enc *OpusEncoder) InDTX() bool
  • func (enc *OpusEncoder) Lookahead() int
• type OpusEncoderConfig
• type SignalType

Constants

const (
	// Auto/default setting
	OpusAuto = int(C.OPUS_AUTO)
	// Maximum bitrate
	BitrateMax = int(C.OPUS_BITRATE_MAX)
)

const (
	// Optimize encoding for VoIP
	AppVoIP = Application(C.OPUS_APPLICATION_VOIP)
	// Optimize encoding for non-voice signals like music
	AppAudio = Application(C.OPUS_APPLICATION_AUDIO)
	// Optimize encoding for low latency applications
	AppRestrictedLowdelay = Application(C.OPUS_APPLICATION_RESTRICTED_LOWDELAY)
)

const (
	// Signal being encoded is voice
	SignalVoice = SignalType(C.OPUS_SIGNAL_VOICE)
	// Signal being encoded is music
	SignalMusic = SignalType(C.OPUS_SIGNAL_MUSIC)
)

const (
	// 4 kHz bandpass
	BandwidthNarrowband = BandwidthType(C.OPUS_BANDWIDTH_NARROWBAND)
	// 6 kHz bandpass
	BandwidthMediumband = BandwidthType(C.OPUS_BANDWIDTH_MEDIUMBAND)
	// 8 kHz bandpass
	BandwidthWideband = BandwidthType(C.OPUS_BANDWIDTH_WIDEBAND)
	// 12 kHz bandpass
	BandwidthSuperwideband = BandwidthType(C.OPUS_BANDWIDTH_SUPERWIDEBAND)
	// 20 kHz bandpass
	BandwidthFullband = BandwidthType(C.OPUS_BANDWIDTH_FULLBAND)
)

const (
	// Select frame size from the argument (default)
	FramesizeArg = FrameSizeType(C.OPUS_FRAMESIZE_ARG)
	// Use 2.5 ms frames
	Framesize2Dot5Ms = FrameSizeType(C.OPUS_FRAMESIZE_2_5_MS)
	// Use 5 ms frames
	Framesize5Ms = FrameSizeType(C.OPUS_FRAMESIZE_5_MS)
	// Use 10 ms frames
	Framesize10Ms = FrameSizeType(C.OPUS_FRAMESIZE_10_MS)
	// Use 20 ms frames
	Framesize20Ms = FrameSizeType(C.OPUS_FRAMESIZE_20_MS)
	// Use 40 ms frames
	Framesize40Ms = FrameSizeType(C.OPUS_FRAMESIZE_40_MS)
	// Use 60 ms frames
	Framesize60Ms = FrameSizeType(C.OPUS_FRAMESIZE_60_MS)
	// Use 80 ms frames
	Framesize80Ms = FrameSizeType(C.OPUS_FRAMESIZE_80_MS)
	// Use 100 ms frames
	Framesize100Ms = FrameSizeType(C.OPUS_FRAMESIZE_100_MS)
	// Use 120 ms frames
	Framesize120Ms = FrameSizeType(C.OPUS_FRAMESIZE_120_MS)
)

Types

type Application

type Application int

Application

type BandwidthType

type BandwidthType int

Bandwidth type

type FrameSizeType

type FrameSizeType int

Frame size type

type OpusDecoder

type OpusDecoder struct {

	// config
	OpusDecoderConfig
	// contains filtered or unexported fields
}

Opus Decoder

func CreateOpusDecoder

func CreateOpusDecoder(config *OpusDecoderConfig) (dec *OpusDecoder, err error)

Create Opus Decoder

func (*OpusDecoder) Close

func (dec *OpusDecoder) Close() error

Close

func (*OpusDecoder) Decode

func (dec *OpusDecoder) Decode(in, out []byte) (int, error)

Decode

type OpusDecoderConfig

type OpusDecoderConfig struct {
	// Sampling rate of input signal (Hz).
	// This must be one of 8000, 12000, 16000, 24000, or 48000.
	SampleRate int
	// Number of channels in input signal.
	MaxChannels int
	// Decoder gain adjustment.
	Gain int
	// Enable inband forward error correction (FEC).
	EnableInbandFEC bool
}

Opus Decoder Config

type OpusEncoder

type OpusEncoder struct {

	// config
	OpusEncoderConfig
	// contains filtered or unexported fields
}

Opus Encoder

func CreateOpusEncoder

func CreateOpusEncoder(config *OpusEncoderConfig) (enc *OpusEncoder, err error)

Create Opus Encoder

func (*OpusEncoder) Close

func (enc *OpusEncoder) Close() error

Close

func (*OpusEncoder) Encode

func (enc *OpusEncoder) Encode(in, out []byte) (int, error)

Encode

func (*OpusEncoder) InDTX

func (enc *OpusEncoder) InDTX() bool

InDTX

func (*OpusEncoder) Lookahead

func (enc *OpusEncoder) Lookahead() int

Lookahead

type OpusEncoderConfig

type OpusEncoderConfig struct {
	// Sampling rate of input signal (Hz).
	// This must be one of 8000, 12000, 16000, 24000, or 48000.
	SampleRate int
	// Number of channels in input signal.
	MaxChannels int
	// Encode mode.
	Application Application
	// Enable discontinuous transmission (DTX).
	EnableDTX bool
	// Enable inband forward error correction (FEC).
	EnableInbandFEC bool
	// Disable almost all use of prediction.
	DisablePrediction bool
	// Disable variable bitrate (VBR).
	DisableVBR bool
	// Disable constrained VBR.
	DisableConstrainedVBR bool
	// Disable the use of phase inversion for intensity stereo.
	DisablePhaseInversion bool
	// Rates from 500 to 512000 bits per second are meaningful,
	// as well as the special values BitrateAuto and BitrateMax.
	Bitrate int
	// Complexity configuration, a value in the range 0-10.
	Complexity int
	// The maximum bandpass that the encoder will select automatically.
	MaxBandwidth BandwidthType
	// Encoder's bandpass to a specific value.
	Bandwidth BandwidthType
	// Expected packet loss percentage.
	PacketLossPercent int
	// The encoder's use of variable duration frames.
	FrameDuration FrameSizeType
	// The type of signal being encoded.
	SignalType SignalType
	// Force mono or stereo.
	ForceChannels int
	// The depth of signal being encoded.
	LSBDepth int
}

Opus Encoder Config

type SignalType

type SignalType int

Signal type