diff --git a/dom/media/wave/WaveDemuxer.cpp b/dom/media/wave/WaveDemuxer.cpp
index a84a410f5841..198834f5e5ff 100644
--- a/dom/media/wave/WaveDemuxer.cpp
+++ b/dom/media/wave/WaveDemuxer.cpp
@@ -10,7 +10,6 @@
 #include <algorithm>
 
 #include "mozilla/Assertions.h"
-#include "mozilla/EndianUtils.h"
 #include "mozilla/Utf8.h"
 #include "BufferReader.h"
 #include "VideoUtils.h"
@@ -166,6 +165,19 @@ bool WAVTrackDemuxer::Init() {
   mInfo->mDuration = Duration();
   mInfo->mChannelMap = mFmtChunk.ChannelMap();
 
+  if (AudioConfig::ChannelLayout::Channels(mInfo->mChannelMap) !=
+      mInfo->mChannels) {
+    AudioConfig::ChannelLayout::ChannelMap defaultForChannelCount =
+        AudioConfig::ChannelLayout(mInfo->mChannels).Map();
+    LOG(("Channel count of %" PRIu32
+         " and channel layout disagree, overriding channel map from %s to %s",
+         mInfo->mChannels,
+         AudioConfig::ChannelLayout::ChannelMapToString(mInfo->mChannelMap)
+             .get(),
+         AudioConfig::ChannelLayout::ChannelMapToString(defaultForChannelCount)
+             .get()));
+    mInfo->mChannelMap = defaultForChannelCount;
+  }
   LOG(("WavDemuxer initialized: %s", mInfo->ToString().get()));
 
   return mInfo->mDuration.IsPositive();
@@ -270,6 +282,8 @@ bool WAVTrackDemuxer::ListChunkParserInit(uint32_t aChunkSize) {
       case 0x494e414d:  // INAM
         mInfo->mTags.AppendElement(MetadataTag("name"_ns, val));
         break;
+      default:
+        LOG(("Metadata key %08x not handled", id));
     }
 
     mHeaderParser.Reset();
diff --git a/dom/media/webaudio/test/mochitest.toml b/dom/media/webaudio/test/mochitest.toml
index 418c52bd96dd..74d17d4fc94b 100644
--- a/dom/media/webaudio/test/mochitest.toml
+++ b/dom/media/webaudio/test/mochitest.toml
@@ -78,6 +78,7 @@ support-files = [
   "half-a-second-2ch-48000.wav",
   "half-a-second-1ch-44100-aac-afconvert.mp4",
   "waveformatextensible.wav",
+  "waveformatextensiblebadmask.wav",
   "sixteen-frames.mp3", # only 16 frames of valid audio
   "../../webrtc/tests/mochitests/mediaStreamPlayback.js",
   "../../webrtc/tests/mochitests/head.js",
diff --git a/dom/media/webaudio/test/test_mediaDecoding.html b/dom/media/webaudio/test/test_mediaDecoding.html
index a6b4f3c4bec6..e76a533e4acb 100644
--- a/dom/media/webaudio/test/test_mediaDecoding.html
+++ b/dom/media/webaudio/test/test_mediaDecoding.html
@@ -247,6 +247,16 @@
       sampleRate: 44100,
       frames: 472,
       duration: 0.01
+    },
+    {
+      // A wav file that has 8 channel, but has a channel mask that doesn't
+      // match the channel count.
+      url: "waveformatextensiblebadmask.wav",
+      valid: true,
+      numberOfChannels: 8,
+      sampleRate: 8000,
+      frames: 80,
+      duration: 0.01
     }
   ];
 
@@ -290,7 +300,7 @@
       is(buffer.numberOfChannels, test.numberOfChannels, "Correct number of channels");
       return;
     }
-    ok(Math.abs(buffer.duration - test.duration) < 1e-3, "Correct duration");
+    ok(Math.abs(buffer.duration - test.duration) < 1e-3, `Correct duration expected ${test.duration} got ${buffer.duration}`);
     if (Math.abs(buffer.duration - test.duration) >= 1e-3) {
       ok(false, "got: " + buffer.duration + ", expected: " + test.duration);
     }
diff --git a/dom/media/webaudio/test/waveformatextensiblebadmask.wav b/dom/media/webaudio/test/waveformatextensiblebadmask.wav
new file mode 100644
index 000000000000..3aa55df98ebe
Binary files /dev/null and b/dom/media/webaudio/test/waveformatextensiblebadmask.wav differ