57 lines
1.7 KiB
JavaScript
57 lines
1.7 KiB
JavaScript
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'use strict';
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// replace username and password with speech to text credentials
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// audio.wav can be found here: https://github.com/watson-developer-cloud/nodejs-wrapper/blob/master/test/resources/audio.wav?raw=true
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var fs = require('fs');
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var opus = require('node-opus');
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var ogg = require('ogg');
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var cp = require('child_process');
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var oggDecoder = new ogg.Decoder();
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oggDecoder.on('stream', function (stream) {
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var opusDecoder = new opus.Decoder();
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// the "format" event contains the raw PCM format
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opusDecoder.on('format', function (format) {
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// format example:
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//{
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// channels: 1,
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// sampleRate: 24000,
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// bitDepth: 16,
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// float: false,
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// signed: true,
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// gain: 0,
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// preSkip: 156,
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// version: 1
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//}
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// convert the signed & bitDepth to an alsa compatible format (`aplay --help format` for full list)
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var alsaFormat;
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if (format.signed && format.bitDepth == 16) {
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alsaFormat = 'S16_LE'; // assume Little Endian
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} else {
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throw new Error('unexpected format: ' + JSON.stringify(format));
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}
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// set up aplay to accept data from stdin
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var aplay = cp.spawn('aplay',['--format=' + alsaFormat, '--rate=' + format.sampleRate, '--channels='+format.channels, '--']);
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// send the raw PCM data to aplay
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opusDecoder.pipe(aplay.stdin);
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// or pipe to node-speaker, a file, etc
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});
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// an "error" event will get emitted if the stream is not a Vorbis stream
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// (i.e. it could be a Theora video stream instead)
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opusDecoder.on('error', console.error);
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stream.pipe(opusDecoder);
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});
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fs.createReadStream('input.opus').pipe(oggDecoder);
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