linx-simulator2/node_modules/lame/examples/mp32wav.js

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2019-09-18 08:11:16 +00:00
/**
* An example using node-lame and node-wav to decode an MP3 file and save it into
* a WAVE file.
*/
var fs = require('fs');
var lame = require('../');
var wav = require('wav');
var filename = process.argv[2];
if (process.stdin.isTTY && !filename) {
// print help
console.error('usage:');
console.error(' decode an mp3 file:');
console.error(' $ %s <infile.mp3> <outfile.wav>', process.argv.join(' '));
console.error(' or decode mp3 data from stdin:');
console.error(' $ cat song.mp3 | %s | ffplay -', process.argv.join(' '));
process.exit(1);
}
// first figure out if we're decoding from a filename, or from stdin
var input;
var output;
if (filename) {
var outfile = process.argv[3];
if (!outfile) {
console.error('FATAL: must specify an output .wav file!');
process.exit(1);
}
console.error('encoding %j', filename);
console.error('to %j', outfile);
input = fs.createReadStream(filename);
output = fs.createWriteStream(outfile);
} else {
input = process.stdin;
output = process.stdout;
}
// start reading the MP3 file from the input
var decoder = new lame.Decoder();
// we have to wait for the "format" event before we can start encoding
decoder.on('format', onFormat);
// and start transferring the data
input.pipe(decoder);
function onFormat (format) {
console.error('MP3 format: %j', format);
// write the decoded MP3 data into a WAV file
var writer = new wav.Writer(format);
decoder.pipe(writer).pipe(output);
}