From 5379d8cc3dc4c8343d1c830f8266fdc8a3981ca1 Mon Sep 17 00:00:00 2001
From: Jakob Ketterl <jakob.ketterl@gmx.de>
Date: Mon, 6 Jan 2020 16:29:23 +0100
Subject: [PATCH] step one: implement upsampling

---
 htdocs/lib/AudioEngine.js | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/htdocs/lib/AudioEngine.js b/htdocs/lib/AudioEngine.js
index 6226825..132df15 100644
--- a/htdocs/lib/AudioEngine.js
+++ b/htdocs/lib/AudioEngine.js
@@ -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;
-};
\ No newline at end of file
+};
+
+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;
+}
\ No newline at end of file