node-lame

LAME is an open-source encoder that encodes and decodes audio to the MP3 file format. For all MP3 needs a Node.js wrapper of the full LAME command line.

The encoder reads WAV-, MP1-, MP2- and MP3-format and encodes it into an MP3 file. The decoder reads MP3-format and decodes it into WAV.

Requirements

• Linux or MacOS (This package is NOT tested on Windows)
• Lame Installed (View instructions below)
• Node 12.20.* or newer

Installation

You can install it with npm:

$ npm install node-lame

If you have not installed LAME yet, please use the following instruction.

Install on Debian

$ sudo apt-get install lame

Install on MacOS with brew

$ brew install lame

Install on Windows

1. Go to the the Lame Download Page and download the EXE or ZIP file.
2. Navigate to the directory Lame was installed in (most commonly C:\Program Files (x86)\Lame For Audacity).
3. Add the directory to your Environment Variables.

Examples

Encode from file to file

const Lame = require("node-lame").Lame;

const encoder = new Lame({
    output: "./audio-files/demo.mp3",
    bitrate: 192,
}).setFile("./audio-files/demo.wav");

encoder
    .encode()
    .then(() => {
        // Encoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

Encode from file to buffer

const Lame = require("node-lame").Lame;

const encoder = new Lame({
    output: "buffer",
    bitrate: 192,
}).setFile("./audio-files/demo.wav");

encoder
    .encode()
    .then(() => {
        // Encoding finished
        const buffer = encoder.getBuffer();
    })
    .catch((error) => {
        // Something went wrong
    });

Encode from buffer to file

[...]

const Lame = require("node-lame").Lame;

const encoder = new Lame({
    "output": "./audio-files/demo.mp3",
    "bitrate": 192
}).setBuffer(audioFileBuffer);

encoder.encode()
    .then(() => {
        // Encoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

Encode from buffer to buffer

[...]

const Lame = require("node-lame").Lame;

const encoder = new Lame({
    "output": "buffer",
    "bitrate": 192
}).setBuffer(audioFileBuffer);

encoder.encode()
    .then(() => {
        // Encoding finished
        const buffer = encoder.getBuffer();
    })
    .catch((error) => {
        // Something went wrong
    });

Get status of encoder as object

const Lame = require("node-lame").Lame;

const encoder = new Lame({
    output: "buffer",
    bitrate: 192,
}).setFile("./audio-files/demo.wav");

encoder
    .encode()
    .then(() => {
        // Encoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

const status = encoder.getStatus();

Get status of encoder as EventEmitter

const Lame = require("node-lame").Lame;

const encoder = new Lame({
    output: "buffer",
    bitrate: 192,
}).setFile("./audio-files/demo.wav");

const emitter = encoder.getEmitter();

emitter.on("progress", ([progress, eta]) => {
    // On progress of encoding. Progress in percent and estimated time of arrival as mm:ss
});

emitter.on("finish", () => {
    // On finish
});

emitter.on("error", (error) => {
    // On error
});

encoder
    .encode()
    .then(() => {
        // Encoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

Decode from file to file

const Lame = require("node-lame").Lame;

const decoder = new Lame({
    output: "./audio-files/demo.wav",
}).setFile("./audio-files/demo.mp3");

decoder
    .decode()
    .then(() => {
        // Decoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

Decode from file to buffer

const Lame = require("node-lame").Lame;

const decoder = new Lame({
    output: "buffer",
}).setFile("./audio-files/demo.mp3");

decoder
    .decode()
    .then(() => {
        // Decoding finished
        const buffer = decoder.getBuffer();
    })
    .catch((error) => {
        // Something went wrong
    });

Decode from buffer to file

[...]

const Lame = require("node-lame").Lame;

const decoder = new Lame({
    "output": "./audio-files/demo.wav"
}).setBuffer(mp3InputBuffer);

decoder.decode()
    .then(() => {
        // Decoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

Decode from buffer to buffer

[...]

const Lame = require("node-lame").Lame;

const decoder = new Lame({
    "output": "buffer"
}).setBuffer(mp3InputBuffer);

decoder.decode()
    .then(() => {
        // Decoding finished
        const buffer = decoder.getBuffer();
    })
    .catch((error) => {
        // Something went wrong
    });

Get status of decoder as object

const Lame = require("node-lame").Lame;

const decoder = new Lame({
    output: "buffer",
}).setFile("./audio-files/demo.mp3");

decoder
    .encode()
    .then(() => {
        // Decoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

const status = decoder.getStatus();

Get status of decoder as EventEmitter

const Lame = require("node-lame").Lame;

const decoder = new Lame({
    output: "buffer",
}).setFile("./audio-files/demo.mp3");

const emitter = decoder.getEmitter();

emitter.on("progress", ([progress]) => {
    // On progress of decoder; in percent
});

emitter.on("finish", () => {
    // On finish
});

emitter.on("error", (error) => {
    // On error
});

decoder
    .decode()
    .then(() => {
        // Decoding finished
    })
    .catch((error) => {
        // Something went wrong
    });

All options

Option	Description	Values	Default
output	Output filename	Path
raw	Assume the input file is raw pcm. Sampling rate and mono/stereo/jstereo must be specified. For each stereo sample, LAME expects the input data to be ordered left channel first, then right channel. By default, LAME expects them to be signed integers with a bitwidth of 16.	boolean	false
swap-bytes	Swap bytes in the input file or output file when using decoding. For sorting out little endian/big endian type problems.	boolean	false
sfreq	Required only for raw PCM input files. Otherwise it will be determined from the header of the input file. LAME will automatically resample the input file to one of the supported MP3 samplerates if necessary.	8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48	undefined
bitwidth	Required only for raw PCM input files. Otherwise it will be determined from the header of the input file.	8, 16, 24, 32	16
signed	Required only for raw PCM input files. Instructs LAME that the samples from the input are signed.	boolean	false; true for 16, 24 and 32 bits raw pcm data
unsigned	Required only for raw PCM input files and only available at bitwidth 8. Instructs LAME that the samples from the input are unsigned (the default for 8 bits raw pcm data, where 0x80 is zero).	boolean	undefined
little-endian	Required only for raw PCM input files. Instructs LAME that the samples from the input are in little-endian form.	boolean	undefined
big-endian	Required only for raw PCM input files. Instructs LAME that the samples from the input are in big-endian form.	boolean	undefined
mp2Input	Assume the input file is a MPEG Layer II (ie MP2) file. If the filename ends in ".mp2" LAME will assume it is a MPEG Layer II file.	boolean	undefined
mp3Input	Assume the input file is a MP3 file. Useful for downsampling from one mp3 to another.	boolean	undefined
mode	Details see LAME man page.	s simple stereo, j joint stereo, f forced MS stereo, d dual mono, m mono, l left channel only, r right channel only	j or s (see details)
to-mono	Mix the stereo input file to mono and encode as mono. The downmix is calculated as the sum of the left and right channel, attenuated by 6 dB.	boolean	false
channel-different-block-sizes	Allows the left and right channels to use different block size types.	boolean	false
freeformat	Produces a free format bitstream. With this option, you can use bitrate with any bitrate higher than 8 kbps.	FreeAmp up to 440 kbps, in_mpg123 up to 560 kbps, l3dec up to 310 kbps, LAME up to 560 kbps, MAD up to 640 kbps	undefined
disable-info-tag	Disable writing of the INFO Tag on encoding.	boolean	false
comp	Instead of choosing bitrate, using this option, user can choose compression ratio to achieve.	number	undefined
scale	Scales input volume by n. This just multiplies the PCM data (after it has been converted to floating point) by n.	number	1
scale-l	Same as scale, but for left channel only.	number	undefined
scale-r	Same as scale, but for right channel only.	number	undefined
replaygain-fast	Compute ReplayGain fast but slightly inaccurately. Details see LAME man page.	boolean	false
replaygain-accurate	Compute ReplayGain more accurately and find the peak sample. Details see LAME man page.	boolean	false
no-replaygain	Disable ReplayGain analysis. By default ReplayGain analysis is enabled. Details see LAME man page.	boolean	false
clip-detect	Clipping detection.	boolean	false
preset	Use one of the built-in presets. Details see LAME man page.	medium, standard, extreme or insane	undefined
noasm	Disable specific assembly optimizations. Quality will not increase, only speed will be reduced.	mmx, 3dnow or sse	undefined (probably depending on OS)
quality	Bitrate is of course the main influence on quality. The higher the bitrate, the higher the quality. But for a given bitrate, we have a choice of algorithms to determine the best scalefactors and Huffman encoding (noise shaping).	0 (best) to 9 (worst)	5
bitrate	For MPEG-1 (sampling frequencies of 32, 44.1 and 48 kHz): n = 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320; For MPEG-2 (sampling frequencies of 16, 22.05 and 24 kHz): n = 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160; For MPEG-2.5 (sampling frequencies of 8, 11.025 and 12 kHz): n = 8, 16, 24, 32, 40, 48, 56, 64	See description	128 for MPEG1 and 64 for MPEG2
force-bitrate	Strictly enforce the bitrate option. This is mainly for use with hardware players that do not support low bitrate mp3.	boolean	false
cbr	Enforce use of constant bitrate.	boolean	false
abr	ABR (average bitrate) options. Turns on encoding with a targeted average bitrate of n kbits, allowing to use frames of different sizes.	8 to 310	undefined
vbr	Use variable bitrate.	boolean	false
vbr-quality	Enable vbr and specifies the value of VBR quality.	0 (best) to 9 (worst)	4
ignore-noise-in-sfb21	LAME ignore noise in sfb21, like in CBR.	boolean	false
emp	All this does is set a flag in the MP3 header bitstream. If you have a PCM input file where one of the above types of (obsolete) emphasis has been applied, you can set this flag in LAME. Then the mp3 decoder should de-emphasize the output during playback, although most decoders ignore this flag.	n none, 5 0/15 microseconds, c citt j.17	n
mark-as-copyrighted	Mark the encoded file as being copyrighted.	boolean	false
mark-as-copy	Mark the encoded file as being a copy.	boolean	false
crc-error-protection	Turn on CRC error protection.It will add a cyclic redundancy check (CRC) code in each frame, allowing to detect transmission errors that could occur on the MP3 stream.	boolean	false
nores	Disable the bit reservoir. Each frame will then become independent from previous ones, but the quality will be lower.	boolean	false
strictly-enforce-ISO	With this option, LAME will enforce the 7680 bit limitation on total frame size.	boolean	false
lowpass	Set a lowpass filtering frequency in kHz. Frequencies specified one will be cutoff.	number	undefined
lowpass-width	Set the width of the lowpass filter in percent.	number	15
highpass	Set an highpass filtering frequency in kHz.	number	undefined
highpass-width	Set the width of the highpass filter in percent.	number	15
resample	Output sampling frequency (for encoding). If not specified, LAME will automatically resample the input when using high compression ratios.	8, 11.025, 12, 16, 22.05, 24, 32, 44.1, 48	undefined
meta	Meta data for MP3.	Object	undefined

Meta options

Option	Description	Values	Default
title	Set title tag (max 30 chars for version 1 tag).	String	undefined
artist	Set artist tag (max 30 chars for version 1 tag).	String	undefined
album	Set album tag (max 30 chars for version 1 tag).	String	undefined
year	Set year tag.	String	undefined
comment	Set user-defined text (max 30 chars for v1 tag, 28 for v1.1).	String	undefined
track	Set track tag, with or without number of total tracks.	String	undefined
genre	Set genre tag (max 30 chars for version 1 tag).	String	undefined
artwork	Set album artwork image (path to jpeg/png/gif file, v2.3 tag).	String	undefined
add-id3v2	Force addition of version 2 tag.	boolean	false
id3v1-only	Add only a version 1 tag.	boolean	false
id3v2-only	Add only a version 2 tag.	boolean	false
id3v2-latin1	Add meta options in ISO-8859-1 text encoding.	boolean	false
id3v2-utf16	Add meta options in unicode text encoding.	boolean	false
space-id3v1	Pad version 1 tag with spaces instead of nulls.	boolean	false
pad-id3v2	Same as pad-id3v2-size value 128	boolean	false
pad-id3v2-size	Adds version 2 tag, pad with extra "num" bytes.	number	undefined
ignore-tag-errors	Ignore errors in values passed for tags, use defaults in case an error occurs	boolean	false
genre-list	Print alphabetically sorted ID3 genre list and exit	string	undefined

Option description text from LAME man page. Based on LAME version 3.99.5 from Feb 28, 2012.