Added decibel event to Android - Shows decibel level when user is rec…

android/src/main/java/com/goodatlas/audiorecord/RNAudioRecordModule.java

@@ -110,6 +110,23 @@ public void run() {
                         // skip first 2 buffers to eliminate "click sound"
                         if (bytesRead > 0 && ++count > 2) {
                             base64Data = Base64.encodeToString(buffer, Base64.NO_WRAP);
+                            // Check decibels in 16 bit
+                            if (audioFormat == AudioFormat.ENCODING_PCM_16BIT) {
+                                double p2 = buffer[buffer.length-1];
+                                double decibel;
+                                if (p2==0) {
+                                    decibel=Double.NEGATIVE_INFINITY;
+                                    eventEmitter.emit("decibel", decibel);
+                                } else {
+                                    decibel = 20.0*Math.log10(p2/65535.0);
+                                    if (Double.isNaN(decibel)) {
+                                        eventEmitter.emit("decibel", Double.NEGATIVE_INFINITY);
+                                    } else {
+                                        eventEmitter.emit("decibel", decibel);
+                                    }
+                                }
+
+                            }
                             eventEmitter.emit("data", base64Data);
                             os.write(buffer, 0, bytesRead);
                         }

index.js

@@ -9,7 +9,8 @@ AudioRecord.start = () => RNAudioRecord.start();
 AudioRecord.stop = () => RNAudioRecord.stop();
 
 const eventsMap = {
-  data: 'data'
+  data: 'data',
+  decibel: 'decibel'
 };
 
 AudioRecord.on = (event, callback) => {