--- a/dom/media/platforms/agnostic/WAVDecoder.cpp
+++ b/dom/media/platforms/agnostic/WAVDecoder.cpp
@@ -112,17 +112,17 @@ WaveDataDecoder::ProcessDecode(MediaRawD
           int32_t v = aReader.ReadLE24();
           buffer[i * mInfo.mChannels + j] =
               Int24bitToAudioSample<AudioDataValue>(v);
         }
       }
     }
   }
 
-  auto duration = media::TimeUnit::FromMicroseconds(frames / mInfo.mRate);
+  auto duration = FramesToTimeUnit(frames, mInfo.mRate);
 
   return DecodePromise::CreateAndResolve(
     DecodedData{ new AudioData(aOffset, aSample->mTime, duration, frames,
                                Move(buffer), mInfo.mChannels, mInfo.mRate) },
     __func__);
 }
 
 RefPtr<MediaDataDecoder::DecodePromise>