Bug 1656438 - Fix the unit of the desired buffering. r=padenot

Comments mention 5ms, but code says it's 50ms.

Differential Revision: https://phabricator.services.mozilla.com/D89761

dom/media/AudioDriftCorrection.h

@@ -28,7 +28,7 @@ namespace mozilla {
  * performance impact.
  *
  * The pref `media.clock drift.buffering` can be used to configure the desired
- * internal buffering. Right now it is at 5ms. But it can be increased if there
+ * internal buffering. Right now it is at 50ms. But it can be increased if there
  * are audio quality problems.
  */
 class ClockDrift final {
@@ -71,7 +71,7 @@ class ClockDrift final {
 
  private:
   void CalculateCorrection(int aBufferedFrames) {
-    // We want to maintain 4 ms buffered
+    // We want to maintain the desired buffer
     int32_t bufferedFramesDiff = aBufferedFrames - mDesiredBuffering;
     int32_t resampledSourceClock = mSourceClock + bufferedFramesDiff;
     if (mTargetRate != mSourceRate) {
@@ -152,7 +152,7 @@ class AudioDriftCorrection final {
  public:
   AudioDriftCorrection(int32_t aSourceRate, int32_t aTargetRate)
       : mDesiredBuffering(
-            std::max(1, Preferences::GetInt("media.clockdrift.buffering", 5)) *
+            std::max(5, Preferences::GetInt("media.clockdrift.buffering", 50)) *
             aSourceRate / 1000),
         mTargetRate(aTargetRate),
         mClockDrift(aSourceRate, aTargetRate, mDesiredBuffering),

modules/libpref/init/StaticPrefList.yaml

@@ -6757,11 +6757,11 @@
   value: false
 #endif
 
-# ClockDrift desired buffering
+# ClockDrift desired buffering in milliseconds
 - name: media.clockdrift.buffering
   type: int32_t
   mirror: always
-  value: 5
+  value: 50
 
 # If a resource is known to be smaller than this size (in kilobytes), a
 # memory-backed MediaCache may be used; otherwise the (single shared global)