1 files changed, 40 insertions, 0 deletions
diff --git a/assets/js/normalizer.js b/assets/js/normalizer.js
new file mode 100644
index 0000000..c18d242
--- /dev/null
+++ b/assets/js/normalizer.js
@@ -0,0 +1,40 @@
+window.currentNormalizationContext = null;
+window.currentNormalizationContext2 = null;
+window.currentNormalizationContext3 = null;
+
+function normalizeAudio(ab, gainBoost) {
+    ab = ab.slice(0);
+
+    return new Promise((res) => {
+        let currentNormalizationProfile = currentNormalizationContext.createGain();
+        currentNormalizationProfile.gain.value = (1.0 + gainBoost) / 10.0;
+
+        if (localStorage.getItem("normalize") === "false") res(currentNormalizationProfile);
+
+        currentNormalizationContext.decodeAudioData(ab).then(function(decodedData) {
+            let decodedBuffer = decodedData.getChannelData(0);
+            let sliceLen = Math.floor(decodedData.sampleRate * 0.05);
+            let averages = [];
+            let sum = 0.0;
+
+            for (let i = 0; i < decodedBuffer.length; i++) {
+                sum += decodedBuffer[i] ** 2;
+                if (i % sliceLen === 0) {
+                    sum = Math.sqrt(sum / sliceLen);
+                    averages.push(sum);
+                    sum = 0;
+                }
+            }
+
+            averages.sort(function(a, b) { return a - b; });
+            let a = averages[Math.floor(averages.length * 0.95)];
+
+            let gain = (1.0 + gainBoost) / a;
+            gain = gain / 10.0;
+
+            console.log("Calculated gain:", gain);
+            currentNormalizationProfile.gain.value = gain;
+            res(currentNormalizationProfile);
+        });
+    });
+}
+\ No newline at end of file