mirror of
https://github.com/musix-org/musix-oss
synced 2024-11-14 03:30:18 +00:00
77 lines
1.8 KiB
JavaScript
77 lines
1.8 KiB
JavaScript
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"use strict";
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var opus = require('../../');
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var fs = require('fs');
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//
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// Generate a sin tone.
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//
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var freq = 123;
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var time = 5;
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var rate = 48000;
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// Allocate a buffer for the tone. We use 16-bit samples.
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var samples = rate*time;
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var length = samples*2;
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var b = Buffer.alloc(length);
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// Generate the tone.
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for( var i = 0; i < rate*time; i++ ) {
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var value = Math.round( Math.sin( 2*Math.PI*i*freq/rate ) * Math.pow( 2, 14 ) );
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b.writeInt16LE( value, i*2 );
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}
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//
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// Create the encoder.
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//
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// Use 20ms frames.
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var frame_size = rate * 0.02;
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var encoder = new opus.OpusEncoder( rate );
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// Open the output streams.
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var output = fs.createWriteStream( 'out.opus' );
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var input_raw = fs.createWriteStream( 'in.pcm' );
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var output_raw = fs.createWriteStream( 'out.pcm' );
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var read = 0;
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while( b.length > 0 ) {
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var size = Math.min( b.length, frame_size );
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// If the input buffer is smaller than the frame_size, copy it into a new 0-padded buffer.
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if( size < frame_size ) {
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var temp = Buffer.alloc( frame_size );
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temp.fill(0);
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b.copy( temp );
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b = temp;
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}
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// We encode frame_size 16-bit samples. This requires a frame_size*2 buffer of bytes.
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var bufferSize = frame_size * 2;
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var toEncode = b.slice(0, bufferSize);
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console.log( frame_size );
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// Encode and decode.
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var encoded = encoder.encode( toEncode );
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var decoded = encoder.decode( encoded );
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// Write the results in the output files.
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input_raw.write( toEncode );
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output.write( encoded );
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output_raw.write( decoded );
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// Move the buffer forward by the buffer size.
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b = b.slice( bufferSize );
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}
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output.end();
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input_raw.end();
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output_raw.end();
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console.log( 'Wrote following files.' );
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console.log( 'in.pcm : Input PCM signal' );
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console.log( 'out.opus : OPUS encoded input signal' );
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console.log( 'out.pcm : Decoded PCM signal' );
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