diff --git a/modules/audio_device/audio_device_data_observer.cc b/modules/audio_device/audio_device_data_observer.cc
index 5f7259d13f..bcec3d5574 100644
--- a/modules/audio_device/audio_device_data_observer.cc
+++ b/modules/audio_device/audio_device_data_observer.cc
@@ -71,6 +71,11 @@ class ADMWrapper : public AudioDeviceModule, public AudioTransport {
                            int64_t* elapsed_time_ms,
                            int64_t* ntp_time_ms) override {
     int32_t res = 0;
+    // Set out parameters to safe values to be sure not to return corrupted
+    // data.
+    nSamplesOut = 0;
+    *elapsed_time_ms = -1;
+    *ntp_time_ms = -1;
     // Request data from audio transport.
     if (audio_transport_) {
       res = audio_transport_->NeedMorePlayData(
diff --git a/modules/audio_device/include/audio_device_defines.h b/modules/audio_device/include/audio_device_defines.h
index bb9a0db859..0495442ebe 100644
--- a/modules/audio_device/include/audio_device_defines.h
+++ b/modules/audio_device/include/audio_device_defines.h
@@ -45,6 +45,7 @@ class AudioTransport {
                                           const bool keyPressed,
                                           uint32_t& newMicLevel) = 0;  // NOLINT
 
+  // Implementation has to setup safe values for all specified out parameters.
   virtual int32_t NeedMorePlayData(const size_t nSamples,
                                    const size_t nBytesPerSample,
                                    const size_t nChannels,
diff --git a/modules/audio_device/include/test_audio_device.cc b/modules/audio_device/include/test_audio_device.cc
index b6748228b5..8ee21601f0 100644
--- a/modules/audio_device/include/test_audio_device.cc
+++ b/modules/audio_device/include/test_audio_device.cc
@@ -174,8 +174,8 @@ class TestAudioDeviceModuleImpl
       }
       if (rendering_) {
         size_t samples_out = 0;
-        int64_t elapsed_time_ms = 0;
-        int64_t ntp_time_ms = 0;
+        int64_t elapsed_time_ms = -1;
+        int64_t ntp_time_ms = -1;
         const int sampling_frequency = renderer_->SamplingFrequency();
         audio_callback_->NeedMorePlayData(
             SamplesPerFrame(sampling_frequency), 2, renderer_->NumChannels(),