diff --git a/scripts/save-tracks.js b/scripts/save-tracks.js
index 251337c..dd0f694 100644
--- a/scripts/save-tracks.js
+++ b/scripts/save-tracks.js
@@ -16,7 +16,7 @@ function createWorker(fn) {
   return new Worker(url)
 }
 
-const saveFileWorker = createWorker(() => {
+const saveFileWorkerFn = () => {
   const log = (...args) => {
     console.log.apply(null, ['[webrtcperf-savefileworker]', ...args])
   }
@@ -155,17 +155,24 @@ const saveFileWorker = createWorker(() => {
       readable.pipeTo(writableStream)
     }
   }
-})
+}
 
+let saveFileWorker = null
 const savingTracks = {
   audio: new Set(),
   video: new Set(),
 }
 
-saveFileWorker.onmessage = event => {
-  const { name, error, kind, id } = event.data
-  log(`saveFileWorker name=${name} kind=${kind} id=${id} error=${error}`)
-  savingTracks[kind].delete(id)
+const getSaveFileWorker = () => {
+  if (!saveFileWorker) {
+    saveFileWorker = createWorker(saveFileWorkerFn)
+    saveFileWorker.onmessage = event => {
+      const { name, error, kind, id } = event.data
+      log(`saveFileWorker name=${name} kind=${kind} id=${id} error=${error}`)
+      savingTracks[kind].delete(id)
+    }
+  }
+  return saveFileWorker
 }
 
 window.saveMediaTrack = async (
@@ -198,7 +205,7 @@ window.saveMediaTrack = async (
   const { readable } = new window.MediaStreamTrackProcessor({ track })
 
   log(`saveMediaTrack ${filename}`)
-  saveFileWorker.postMessage(
+  getSaveFileWorker().postMessage(
     {
       id,
       url,
diff --git a/src/config.ts b/src/config.ts
index 73d38d0..941bbd8 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -465,9 +465,10 @@ use the host X server instance.`,
     arg: 'enable-gpu',
   },
   enableBrowserLogging: {
-    doc: `It enables the Chromium browser logging to standard output.`,
-    format: 'Boolean',
-    default: false,
+    doc: `It enables the Chromium browser logging, e.g. "--v=0" (see https://www.chromium.org/for-testers/enable-logging/).`,
+    format: String,
+    nullable: true,
+    default: '',
     env: 'ENABLE_BROWSER_LOGGING',
     arg: 'enable-browser-logging',
   },
diff --git a/src/session.ts b/src/session.ts
index 28c4476..d152499 100644
--- a/src/session.ts
+++ b/src/session.ts
@@ -119,7 +119,7 @@ export type SessionParams = {
   videoHeight: number
   videoFramerate: number
   enableGpu: string
-  enableBrowserLogging: boolean
+  enableBrowserLogging: string
   startTimestamp: number
   sessions: number
   tabsPerSession: number
@@ -187,7 +187,7 @@ export class Session extends EventEmitter {
   private readonly videoHeight: number
   private readonly videoFramerate: number
   private readonly enableGpu: string
-  private readonly enableBrowserLogging: boolean
+  private readonly enableBrowserLogging: string
   private readonly startTimestamp: number
   private readonly sessions: number
   private readonly tabsPerSession: number
@@ -585,7 +585,7 @@ export class Session extends EventEmitter {
     }
 
     if (this.enableBrowserLogging) {
-      args = args.concat(['--enable-logging=stderr', '--vmodule=*/webrtc/*=1'])
+      args = args.concat(['--enable-logging=stderr', this.enableBrowserLogging])
     }
 
     return args
@@ -686,7 +686,7 @@ exec sg ${group} -c /tmp/webrtcperf-launcher-${mark}-browser`,
           executablePath,
           handleSIGINT: false,
           env,
-          dumpio: this.enableBrowserLogging,
+          dumpio: !!this.enableBrowserLogging,
           // devtools: true,
           ignoreHTTPSErrors: true,
           defaultViewport: {