update demos

demo/nodejs/README.md

@@ -44,6 +44,14 @@ cobra-file-demo --access_key ${ACCESS_KEY} --input_audio_file_path ${AUDIO_PATH}
 Replace `${ACCESS_KEY}` with yours obtained from Picovoice Console and `${AUDIO_PATH}` with a path to an audio file you
 wish to use for voice activity detection.
 
+The threshold of the engine can be tuned using the `threshold` input argument:
+
+```console
+cobra-file-demo --access_key ${ACCESS_KEY} --input_audio_file_path ${AUDIO_PATH} --threshold ${DETECTION_THRESHOLD}
+```
+
+Threshold is a floating point number within `[0, 1]`. A higher threshold reduces the miss rate at the cost of increased false alarm rate.
+
 ### Microphone Demo
 
 You need a working microphone connected to your machine for this demo. Run the following in the terminal:

demo/nodejs/file.js

@@ -31,6 +31,10 @@ program
   .option(
     "-l, --library_file_path <string>",
     "absolute path to cobra dynamic library"
+  )
+  .option(
+    "-t --threshold <string>",
+    "Threshold for the probability of voice activity"
   );
 
 if (process.argv.length < 2) {
@@ -42,6 +46,7 @@ function fileDemo() {
   let audioPath = program["input_audio_file_path"];
   let accessKey = program["access_key"];
   let libraryFilePath = program["library_file_path"];
+  let threshold = program["threshold"] ?? 0.8;
 
   let engineInstance = new Cobra(accessKey, {
     libraryPath: libraryFilePath,
@@ -70,13 +75,20 @@ function fileDemo() {
 
   let frames = getInt16Frames(inputWaveFile, engineInstance.frameLength);
 
-  let voiceProbabilities = [];
-  for (let frame of frames) {
-    const voiceProbability = engineInstance.process(frame);
-    voiceProbabilities.push(voiceProbability);
+  const printedNums = new Set();
+  for (let i = 0; i < frames.length; i++) {
+    const result = engineInstance.process(frames[i]);
+    const timestamp = (
+      (i * engineInstance.frameLength) /
+      engineInstance.sampleRate
+    ).toFixed(1);
+
+    if (result >= threshold && !printedNums.has(timestamp)) {
+      console.log(`Detected voice activity at ${timestamp} sec`);
+      printedNums.add(timestamp);
+    }
   }
 
-  console.log(voiceProbabilities);
   engineInstance.release();
 }
 

demo/nodejs/mic.js

@@ -90,7 +90,16 @@ async function micDemo() {
     const pcm = await recorder.read();
     try {
       const voiceProbability = engineInstance.process(pcm);
-      console.log(voiceProbability);
+      const percentage = voiceProbability * 100;
+      const barLength = Math.floor((percentage / 10) * 3);
+      const emptyLength = 30 - barLength;
+      const spacer = ` `.repeat(3 - percentage.toFixed(0).length);
+
+      process.stdout.write(
+        `\r[${spacer}${percentage.toFixed(0)}]|${"█".repeat(
+          barLength
+        )}${" ".repeat(emptyLength)}|`
+      );
     } catch (err) {
       if (err instanceof CobraActivationLimitReachedError) {
         console.error(
@@ -106,6 +115,7 @@ async function micDemo() {
   recorder.stop();
   recorder.release();
   engineInstance.release();
+  process.stdout.write("\n");
   process.exit();
 }