diff --git a/media/engine/webrtc_voice_engine.cc b/media/engine/webrtc_voice_engine.cc
index 38dc346..016c00f 100644
--- a/media/engine/webrtc_voice_engine.cc
+++ b/media/engine/webrtc_voice_engine.cc
@@ -11,7 +11,6 @@
 #include "media/engine/webrtc_voice_engine.h"
 
 #include <algorithm>
-#include <cstdio>
 #include <functional>
 #include <string>
 #include <utility>
@@ -43,6 +42,7 @@
 #include "rtc_base/race_checker.h"
 #include "rtc_base/strings/audio_format_to_string.h"
 #include "rtc_base/strings/string_builder.h"
+#include "rtc_base/strings/string_format.h"
 #include "rtc_base/third_party/base64/base64.h"
 #include "rtc_base/trace_event.h"
 #include "system_wrappers/include/field_trial.h"
@@ -2051,14 +2051,19 @@
 
 bool WebRtcVoiceMediaChannel::SetOutputVolume(uint32_t ssrc, double volume) {
   RTC_DCHECK(worker_thread_checker_.IsCurrent());
+  RTC_LOG(LS_INFO) << rtc::StringFormat("WRVMC::%s({ssrc=%u}, {volume=%.2f})",
+                                        __func__, ssrc, volume);
   const auto it = recv_streams_.find(ssrc);
   if (it == recv_streams_.end()) {
-    RTC_LOG(LS_WARNING) << "SetOutputVolume: no recv stream " << ssrc;
+    RTC_LOG(LS_WARNING) << rtc::StringFormat(
+        "WRVMC::%s => (WARNING: no receive stream for SSRC %u)", __func__,
+        ssrc);
     return false;
   }
   it->second->SetOutputVolume(volume);
-  RTC_LOG(LS_INFO) << "SetOutputVolume() to " << volume
-                   << " for recv stream with ssrc " << ssrc;
+  RTC_LOG(LS_INFO) << rtc::StringFormat(
+      "WRVMC::%s => (stream with SSRC %u now uses volume %.2f)", __func__, ssrc,
+      volume);
   return true;
 }
 
diff --git a/pc/remote_audio_source.cc b/pc/remote_audio_source.cc
index 301cd3f..18a4ed2 100644
--- a/pc/remote_audio_source.cc
+++ b/pc/remote_audio_source.cc
@@ -22,6 +22,7 @@
 #include "rtc_base/location.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/numerics/safe_conversions.h"
+#include "rtc_base/strings/string_format.h"
 #include "rtc_base/thread.h"
 #include "rtc_base/thread_checker.h"
 
@@ -102,6 +103,8 @@
 void RemoteAudioSource::SetVolume(double volume) {
   RTC_DCHECK_GE(volume, 0);
   RTC_DCHECK_LE(volume, 10);
+  RTC_LOG(LS_INFO) << rtc::StringFormat("RAS::%s({volume=%.2f})", __func__,
+                                        volume);
   for (auto* observer : audio_observers_) {
     observer->OnSetVolume(volume);
   }