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step one: implement upsampling

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This commit is contained in:
Jakob Ketterl 2020-01-06 16:29:23 +01:00
parent 9187bb4371
commit 5379d8cc3d
1 changed files with 16 additions and 3 deletions
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19
htdocs/lib/AudioEngine.js
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@ -18,7 +18,8 @@ function AudioEngine(maxBufferLength, audioReporter) {
this.compression = 'none';
this.setupResampling();
this.resampler = new sdrjs.RationalResamplerFF(this.resamplingFactor, 1);
//this.resampler = new sdrjs.RationalResamplerFF(this.resamplingFactor, 1);
this.resampler = new Interpolator(this.resamplingFactor);
this.maxBufferSize = maxBufferLength * this.getSampleRate();
}
@ -203,7 +204,7 @@ AudioEngine.prototype.pushAudio = function(data) {
} else {
buffer = new Int16Array(data);
}
buffer = this.resampler.process(sdrjs.ConvertI16_F(buffer));
buffer = this.resampler.process(buffer);
if (this.audioNode.port) {
// AudioWorklets supported
this.audioNode.port.postMessage(buffer);
@ -278,4 +279,16 @@ ImaAdpcmCodec.prototype.decodeNibble = function(nibble) {
this.step = ImaAdpcmCodec.imaStepTable[this.stepIndex];
return this.predictor;
};
};
function Interpolator(factor) {
this.factor = factor;
}
Interpolator.prototype.process = function(data) {
var output = new Float32Array(data.length * this.factor);
for (var i = 0; i < data.length; i++) {
output[i * this.factor] = (data[i] + 0.5) / 32768;
}
return output;
}