diff --git a/dom/media/webrtc/MediaEngineCameraVideoSource.cpp b/dom/media/webrtc/MediaEngineCameraVideoSource.cpp
index 68b456b9e62a..9cd1acff4e03 100644
--- a/dom/media/webrtc/MediaEngineCameraVideoSource.cpp
+++ b/dom/media/webrtc/MediaEngineCameraVideoSource.cpp
@@ -162,6 +162,49 @@ MediaEngineCameraVideoSource::LogConstraints(
        c.mFrameRate.mIdeal.WasPassed()? c.mFrameRate.mIdeal.Value() : 0));
 }
 
+void
+MediaEngineCameraVideoSource::LogCapability(const char* aHeader,
+    const webrtc::CaptureCapability &aCapability, uint32_t aDistance)
+{
+  // RawVideoType and VideoCodecType media/webrtc/trunk/webrtc/common_types.h
+  static const char* const types[] = {
+    "I420",
+    "YV12",
+    "YUY2",
+    "UYVY",
+    "IYUV",
+    "ARGB",
+    "RGB24",
+    "RGB565",
+    "ARGB4444",
+    "ARGB1555",
+    "MJPEG",
+    "NV12",
+    "NV21",
+    "BGRA",
+    "Unknown type"
+  };
+
+  static const char* const codec[] = {
+    "VP8",
+    "VP9",
+    "H264",
+    "I420",
+    "RED",
+    "ULPFEC",
+    "Generic codec",
+    "Unknown codec"
+  };
+
+  LOG(("%s: %4u x %4u x %2u maxFps, %s, %s. Distance = %lu",
+       aHeader, aCapability.width, aCapability.height, aCapability.maxFPS,
+       types[std::min(std::max(uint32_t(0), uint32_t(aCapability.rawType)),
+                      uint32_t(sizeof(types) / sizeof(*types) - 1))],
+       codec[std::min(std::max(uint32_t(0), uint32_t(aCapability.codecType)),
+                      uint32_t(sizeof(codec) / sizeof(*codec) - 1))],
+       aDistance));
+}
+
 bool
 MediaEngineCameraVideoSource::ChooseCapability(
     const MediaTrackConstraints &aConstraints,
@@ -195,6 +238,7 @@ MediaEngineCameraVideoSource::ChooseCapability(
     webrtc::CaptureCapability cap;
     GetCapability(candidate.mIndex, cap);
     candidate.mDistance = GetFitnessDistance(cap, aConstraints, false, aDeviceId);
+    LogCapability("Capability", cap, candidate.mDistance);
     if (candidate.mDistance == UINT32_MAX) {
       candidateSet.RemoveElementAt(i);
     } else {
@@ -234,6 +278,7 @@ MediaEngineCameraVideoSource::ChooseCapability(
 
   // Any remaining multiples all have the same distance. A common case of this
   // occurs when no ideal is specified. Lean toward defaults.
+  uint32_t sameDistance = candidateSet[0].mDistance;
   {
     MediaTrackConstraintSet prefs;
     prefs.mWidth.SetAsLong() = aPrefs.GetWidth();
@@ -268,9 +313,7 @@ MediaEngineCameraVideoSource::ChooseCapability(
     GetCapability(candidateSet[0].mIndex, mCapability);
   }
 
-  LOG(("chose cap %dx%d @%dfps codec %d raw %d",
-       mCapability.width, mCapability.height, mCapability.maxFPS,
-       mCapability.codecType, mCapability.rawType));
+  LogCapability("Chosen capability", mCapability, sameDistance);
   return true;
 }
 
diff --git a/dom/media/webrtc/MediaEngineCameraVideoSource.h b/dom/media/webrtc/MediaEngineCameraVideoSource.h
index f5ce28d490db..8b822a88ad77 100644
--- a/dom/media/webrtc/MediaEngineCameraVideoSource.h
+++ b/dom/media/webrtc/MediaEngineCameraVideoSource.h
@@ -84,6 +84,9 @@ protected:
   static void TrimLessFitCandidates(CapabilitySet& set);
   static void LogConstraints(const dom::MediaTrackConstraintSet& aConstraints,
                              bool aAdvanced);
+static void LogCapability(const char* aHeader,
+                          const webrtc::CaptureCapability &aCapability,
+                          uint32_t aDistance);
   virtual size_t NumCapabilities();
   virtual void GetCapability(size_t aIndex, webrtc::CaptureCapability& aOut);
   bool ChooseCapability(const dom::MediaTrackConstraints &aConstraints,