lame

package module
v0.0.0-...-bb55259 Latest Latest
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 Go to latest Published: Nov 8, 2020 License: MIT Imports: 6 Imported by: 9

README

go-lame

A new generation lamemp3 Go bindings to replace legacy https://github.com/viert/lame

What's new

  • more lame library code bound
  • better id3 tag support
  • used in a real project of mine so is going to be developed and maintained more rapidly and carefully (and hopefully)

Example

package main

import (
	"bufio"
	"os"

    "github.com/viert/go-lame"
)

func main() {
	of, err := os.Create("output.mp3")
	if err != nil {
		panic(err)
	}
	defer of.Close()
	enc := lame.NewEncoder(of)
	defer enc.Close()

	inf, err := os.Open("input.wav")
	if err != nil {
		panic(err)
	}
	defer inf.Close()

	r := bufio.NewReader(inf)
	r.WriteTo(enc)
}

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Encoder 

type Encoder struct {
	// contains filtered or unexported fields
}

Encoder represents a Writer interface to lame encoder

func NewEncoder 

func NewEncoder(w io.Writer) *Encoder

NewEncoder creates a new encoder

func (*Encoder) Brate 

func (e *Encoder) Brate() int

Brate returns current brate compression ratio

func (*Encoder) Close 

func (e *Encoder) Close()

Close closes the encoder if it's not closed yet Note that encoder is being closed automatically on GC

func (*Encoder) Flush 

func (e *Encoder) Flush() (n int, err error)

Flush flushes the encoder buffer

func (*Encoder) HighPassFrequency 

func (e *Encoder) HighPassFrequency() int

HighPassFrequency returns current highpass frequency value

func (*Encoder) HighPassWidth 

func (e *Encoder) HighPassWidth() int

HighPassWidth returns current highpass width value

func (*Encoder) ID3TagAddV2 

func (e *Encoder) ID3TagAddV2()

ID3TagAddV2 forces addition of version 2 tag

func (*Encoder) ID3TagPadV2 

func (e *Encoder) ID3TagPadV2()

ID3TagPadV2 pads version 2 tag with extra 128 bytes

func (*Encoder) ID3TagSetAlbum 

func (e *Encoder) ID3TagSetAlbum(value string)

ID3TagSetAlbum sets id3 album

func (*Encoder) ID3TagSetArtist 

func (e *Encoder) ID3TagSetArtist(value string)

ID3TagSetArtist sets id3 artist

func (*Encoder) ID3TagSetComment 

func (e *Encoder) ID3TagSetComment(value string)

ID3TagSetComment sets id3 comment

func (*Encoder) ID3TagSetGenre 

func (e *Encoder) ID3TagSetGenre(value string) error

ID3TagSetGenre sets id3 genre

func (*Encoder) ID3TagSetPad 

func (e *Encoder) ID3TagSetPad(n int)

ID3TagSetPad pads version 2 tag with extra n bytes

func (*Encoder) ID3TagSetTitle 

func (e *Encoder) ID3TagSetTitle(value string)

ID3TagSetTitle sets id3 title

func (*Encoder) ID3TagSetTrack 

func (e *Encoder) ID3TagSetTrack(value string) error

ID3TagSetTrack sets id3 track 

note that lame accepts a string and returns an error if
track value is out of range

func (*Encoder) ID3TagSetYear 

func (e *Encoder) ID3TagSetYear(value string)

ID3TagSetYear sets id3 year

func (*Encoder) ID3TagSpaceV1 

func (e *Encoder) ID3TagSpaceV1()

ID3TagSpaceV1 sets version 1 tag padding with spaces instead of nulls

func (*Encoder) ID3TagV1Only 

func (e *Encoder) ID3TagV1Only()

ID3TagV1Only sets addition of only a version 1 tag

func (*Encoder) ID3TagV2Only 

func (e *Encoder) ID3TagV2Only()

ID3TagV2Only sets addition of only a version 2 tag

func (*Encoder) ID3V1Tag 

func (e *Encoder) ID3V1Tag() []byte

ID3V1Tag returns version 1 id3 tag

func (*Encoder) ID3V2Tag 

func (e *Encoder) ID3V2Tag() []byte

ID3V2Tag returns version 2 id3 tag

func (*Encoder) InSamplerate 

func (e *Encoder) InSamplerate() int

InSamplerate returns current input sample rate configured

func (*Encoder) InitID3Tag 

func (e *Encoder) InitID3Tag()

InitID3Tag initializes id3 metadata

func (*Encoder) LameTagFrame 

func (e *Encoder) LameTagFrame() []byte

LameTagFrame returns the final LAME-tag frame

  • NOTE:
  • if VBR tags are turned off by the user, or turned off by LAME,
  • this call does nothing and returns 0.
  • NOTE:
  • LAME inserted an empty frame in the beginning of mp3 audio data,
  • which you have to replace by the final LAME-tag frame after encoding.
  • In case there is no ID3v2 tag, usually this frame will be the very first
  • data in your mp3 file. If you put some other leading data into your
  • file, you'll have to do some bookkeeping about where to write this buffer.

func (*Encoder) LowPassFrequency 

func (e *Encoder) LowPassFrequency() int

LowPassFrequency returns current lowpass frequency value

func (*Encoder) LowPassWidth 

func (e *Encoder) LowPassWidth() int

LowPassWidth returns current lowpass width value

func (*Encoder) NumChannels 

func (e *Encoder) NumChannels() int

NumChannels returns current input numchannels value

func (*Encoder) NumSamples 

func (e *Encoder) NumSamples() uint32

NumSamples gets number of samples

func (*Encoder) Quality 

func (e *Encoder) Quality() int

Quality returns current quality value

func (*Encoder) SetBrate 

func (e *Encoder) SetBrate(brate int) error

SetBrate sets one of brate compression ratio. 

default is compression ratio of 11

func (*Encoder) SetHighPassFrequency 

func (e *Encoder) SetHighPassFrequency(frequency int) error

SetHighPassFrequency applies lowpass filtering to frequency in Hz 

0 - lame chooses
-1 - disable lowpass
default is 0

func (*Encoder) SetHighPassWidth 

func (e *Encoder) SetHighPassWidth(frequency int) error

SetHighPassWidth sets the width of transition band in Hz 

default = one polyphase filter band

func (*Encoder) SetInSamplerate 

func (e *Encoder) SetInSamplerate(sampleRate int) error

SetInSamplerate sets input sample rate in Hz 

default is 44100

func (*Encoder) SetLowPassFrequency 

func (e *Encoder) SetLowPassFrequency(frequency int) error

SetLowPassFrequency applies lowpass filtering to frequency in Hz 

0 - lame chooses
-1 - disable lowpass
default is 0

func (*Encoder) SetLowPassWidth 

func (e *Encoder) SetLowPassWidth(frequency int) error

SetLowPassWidth sets the width of transition band in Hz 

default = one polyphase filter band

func (*Encoder) SetMode 

func (e *Encoder) SetMode(mode MpegMode) error

SetMode sets output audio mode 

mode = 0,1,2,3 = stereo, jstereo, dual channel (not supported), mono
default: lame picks based on compression ration and input channels

func (*Encoder) SetNumChannels 

func (e *Encoder) SetNumChannels(num int) error

SetNumChannels sets number of channels in input stream 

default is 2

func (*Encoder) SetNumSamples 

func (e *Encoder) SetNumSamples(numSamples uint32) error

SetNumSamples sets number of samples. 

default = 2^32-1

func (*Encoder) SetQuality 

func (e *Encoder) SetQuality(quality int) error

SetQuality chooses internal algorithm selection. 

True quality is determined by the bitrate
but this variable will effect quality by selecting expensive or cheap algorithms.
quality=0..9.  0=best (very slow).  9=worst.
recommended:  2     near-best quality, not too slow
              5     good quality, fast
              7     ok quality, really fast

func (*Encoder) SetVBR 

func (e *Encoder) SetVBR(mode VBRMode) error

SetVBR sets vbr mode

func (*Encoder) SetVBRHardMin 

func (e *Encoder) SetVBRHardMin(enforce bool) error

SetVBRHardMin when enforce==true, strictly enforces min bitrate 

Normally it will be violated for analog silence

func (*Encoder) SetVBRMaxBitrateKbps 

func (e *Encoder) SetVBRMaxBitrateKbps(kbps int) error

SetVBRMaxBitrateKbps sets max bitrate 

Ignored unless VBRABR mode is used

func (*Encoder) SetVBRMeanBitrateKbps 

func (e *Encoder) SetVBRMeanBitrateKbps(kbps int) error

SetVBRMeanBitrateKbps sets VBR mean bitrate 

Ignored unless VBRABR mode is used

func (*Encoder) SetVBRMinBitrateKbps 

func (e *Encoder) SetVBRMinBitrateKbps(kbps int) error

SetVBRMinBitrateKbps sets min bitrate I gnored unless VBRABR mode is used

func (*Encoder) SetVBRQuality 

func (e *Encoder) SetVBRQuality(quality float64) error

SetVBRQuality sets VBR quality level. 0=highest 9=lowest, Range [0,...,10[

func (*Encoder) SetWriteID3TagAutomatic 

func (e *Encoder) SetWriteID3TagAutomatic(auto bool)

SetWriteID3TagAutomatic sets automatic write of id3 tag 

Normaly lame_init_param writes ID3v2 tags into the audio stream.
Here in Encoder lame_init_param is launched on first write to encoder instance.
Call SetWriteID3TagAutomatic(false) before writing to encoder
to turn off this behaviour and get ID3v2 tag with above function
write it yourself into your file.

func (*Encoder) VBRHardMin 

func (e *Encoder) VBRHardMin() bool

VBRHardMin returns enforced min bitrate value

func (*Encoder) VBRMaxBitrateKbps 

func (e *Encoder) VBRMaxBitrateKbps() int

VBRMaxBitrateKbps returns VBR mean bitrate

func (*Encoder) VBRMeanBitrateKbps 

func (e *Encoder) VBRMeanBitrateKbps() int

VBRMeanBitrateKbps returns VBR mean bitrate

func (*Encoder) VBRMinBitrateKbps 

func (e *Encoder) VBRMinBitrateKbps() int

VBRMinBitrateKbps returns VBR mean bitrate

func (*Encoder) Write 

func (e *Encoder) Write(p []byte) (int, error)

Write implements a default Writer interface

func (*Encoder) WriteID3TagAutomatic 

func (e *Encoder) WriteID3TagAutomatic() bool

WriteID3TagAutomatic returns current automatic tag write flag

type Error 

type Error int

Error lame error type 

const (
	ErrorBufferTooSmall         Error = -1
	ErrorMalloc                 Error = -2
	ErrorParamsNotInitialized   Error = -3
	ErrorPsychoAcousticProblems Error = -4
)

Lame errors

func (Error) Error 

func (e Error) Error() string

type MpegMode 

type MpegMode int

MpegMode is a MPEG mode constants type 

const (
	MpegStereo       MpegMode = C.STEREO
	MpegJointStereo  MpegMode = C.JOINT_STEREO
	MpegDualChannel  MpegMode = C.DUAL_CHANNEL /* LAME doesn't supports this! */
	MpegMono         MpegMode = C.MONO
	MpegNotSet       MpegMode = C.NOT_SET
	MpegMaxIndicator MpegMode = C.MAX_INDICATOR /* Don't use this! It's used for sanity checks. */
)

MPEG modes

type PaddingType 

type PaddingType int

PaddingType is a padding type constants type 

const (
	PadNo           PaddingType = C.PAD_NO
	PadAll          PaddingType = C.PAD_ALL
	PadAdjust       PaddingType = C.PAD_ADJUST
	PadMaxIndicator PaddingType = C.PAD_MAX_INDICATOR /* Don't use this! It's used for sanity checks. */
)

Padding types

type PresetMode 

type PresetMode int

PresetMode is a preset mode constants type 

const (
	PresetABR8   PresetMode = C.ABR_8
	PresetABR320 PresetMode = C.ABR_320
	PresetV9     PresetMode = C.V9
	PresetVBR10  PresetMode = C.VBR_10
	PresetV8     PresetMode = C.V8
	PresetVBR20  PresetMode = C.VBR_20
	PresetV7     PresetMode = C.V7
	PresetVBR30  PresetMode = C.VBR_30
	PresetV6     PresetMode = C.V6
	PresetVBR40  PresetMode = C.VBR_40
	PresetV5     PresetMode = C.V5
	PresetVBR50  PresetMode = C.VBR_50
	PresetV4     PresetMode = C.V4
	PresetVBR60  PresetMode = C.VBR_60
	PresetV3     PresetMode = C.V3
	PresetVBR70  PresetMode = C.VBR_70
	PresetV2     PresetMode = C.V2
	PresetVBR80  PresetMode = C.VBR_80
	PresetV1     PresetMode = C.V1
	PresetVBR90  PresetMode = C.VBR_90
	PresetV0     PresetMode = C.V0
	PresetVBR100 PresetMode = C.VBR_100

	// Compatibility presets
	PresetR3Mix        PresetMode = C.R3MIX
	PresetStandard     PresetMode = C.STANDARD
	PresetExtreme      PresetMode = C.EXTREME
	PresetInsane       PresetMode = C.INSANE
	PresetStandardFast PresetMode = C.STANDARD_FAST
	PresetExtremeFast  PresetMode = C.EXTREME_FAST
	PresetMedium       PresetMode = C.MEDIUM
	PresetMediumFast   PresetMode = C.MEDIUM_FAST
)

Preset modes

type VBRMode 

type VBRMode int

VBRMode is a VBR mode constants type 

const (
	VBROff          VBRMode = C.vbr_off
	VBRMT           VBRMode = C.vbr_mt /* obsolete, same as vbr_mtrh */
	VBRRH           VBRMode = C.vbr_rh
	VBRABR          VBRMode = C.vbr_abr
	VBRMTRH         VBRMode = C.vbr_mtrh
	VBRMaxIndicator VBRMode = C.vbr_max_indicator /* Don't use this! It's used for sanity checks.       */
	VBRDefault      VBRMode = C.vbr_default
)

VBR modes

Source Files

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