--- a/dom/media/platforms/agnostic/VorbisDecoder.cpp
+++ b/dom/media/platforms/agnostic/VorbisDecoder.cpp
@@ -185,53 +185,63 @@ VorbisDataDecoder::DoDecode(MediaRawData
                                     0,
                                     0,
                                     AlignedAudioBuffer(),
                                     mVorbisDsp.vi->channels,
                                     mVorbisDsp.vi->rate));
   }
   while (frames > 0) {
     uint32_t channels = mVorbisDsp.vi->channels;
+    uint32_t rate = mVorbisDsp.vi->rate;
     AlignedAudioBuffer buffer(frames*channels);
     if (!buffer) {
       return -1;
     }
     for (uint32_t j = 0; j < channels; ++j) {
       VorbisPCMValue* channel = pcm[j];
       for (uint32_t i = 0; i < uint32_t(frames); ++i) {
         buffer[i*channels + j] = MOZ_CONVERT_VORBIS_SAMPLE(channel[i]);
       }
     }
 
-    CheckedInt64 duration = FramesToUsecs(frames, mVorbisDsp.vi->rate);
+    CheckedInt64 duration = FramesToUsecs(frames, rate);
     if (!duration.isValid()) {
       NS_WARNING("Int overflow converting WebM audio duration");
       return -1;
     }
-    CheckedInt64 total_duration = FramesToUsecs(mFrames,
-                                                mVorbisDsp.vi->rate);
+    CheckedInt64 total_duration = FramesToUsecs(mFrames, rate);
     if (!total_duration.isValid()) {
       NS_WARNING("Int overflow converting WebM audio total_duration");
       return -1;
     }
 
     CheckedInt64 time = total_duration + aTstampUsecs;
     if (!time.isValid()) {
       NS_WARNING("Int overflow adding total_duration and aTstampUsecs");
       return -1;
     };
 
+    if (!mAudioConverter) {
+      AudioConfig in(AudioConfig::ChannelLayout(channels, VorbisLayout(channels)),
+                     rate);
+      AudioConfig out(channels, rate);
+      mAudioConverter = MakeUnique<AudioConverter>(in, out);
+    }
+    MOZ_ASSERT(mAudioConverter->CanWorkInPlace());
+    AudioSampleBuffer data(Move(buffer));
+    mAudioConverter->Process(data);
+
     aTotalFrames += frames;
     mCallback->Output(new AudioData(aOffset,
                                     time.value(),
                                     duration.value(),
                                     frames,
-                                    Move(buffer),
-                                    mVorbisDsp.vi->channels,
-                                    mVorbisDsp.vi->rate));
+                                    data.Forget(),
+                                    channels,
+                                    rate));
     mFrames += frames;
     if (vorbis_synthesis_read(&mVorbisDsp, frames) != 0) {
       return -1;
     }
 
     frames = vorbis_synthesis_pcmout(&mVorbisDsp, &pcm);
   }
 
@@ -268,11 +278,63 @@ VorbisDataDecoder::Flush()
 /* static */
 bool
 VorbisDataDecoder::IsVorbis(const nsACString& aMimeType)
 {
   return aMimeType.EqualsLiteral("audio/webm; codecs=vorbis") ||
          aMimeType.EqualsLiteral("audio/ogg; codecs=vorbis");
 }
 
+/* static */ const AudioConfig::Channel*
+VorbisDataDecoder::VorbisLayout(uint32_t aChannels)
+{
+  // From https://www.xiph.org/vorbis/doc/Vorbis_I_spec.html
+  // Section 4.3.9.
+  typedef AudioConfig::Channel Channel;
+
+  switch (aChannels) {
+    case 1: // the stream is monophonic
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_MONO };
+      return config;
+    }
+    case 2: // the stream is stereo. channel order: left, right
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_RIGHT };
+      return config;
+    }
+    case 3: // the stream is a 1d-surround encoding. channel order: left, center, right
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_CENTER, AudioConfig::CHANNEL_RIGHT };
+      return config;
+    }
+    case 4: // the stream is quadraphonic surround. channel order: front left, front right, rear left, rear right
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_RIGHT, AudioConfig::CHANNEL_LS, AudioConfig::CHANNEL_RS };
+      return config;
+    }
+    case 5: // the stream is five-channel surround. channel order: front left, center, front right, rear left, rear right
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_CENTER, AudioConfig::CHANNEL_RIGHT, AudioConfig::CHANNEL_LS, AudioConfig::CHANNEL_RS };
+      return config;
+    }
+    case 6: // the stream is 5.1 surround. channel order: front left, center, front right, rear left, rear right, LFE
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_CENTER, AudioConfig::CHANNEL_RIGHT, AudioConfig::CHANNEL_LS, AudioConfig::CHANNEL_RS, AudioConfig::CHANNEL_LFE };
+      return config;
+    }
+    case 7: // surround. channel order: front left, center, front right, side left, side right, rear center, LFE
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_CENTER, AudioConfig::CHANNEL_RIGHT, AudioConfig::CHANNEL_LS, AudioConfig::CHANNEL_RS, AudioConfig::CHANNEL_RCENTER, AudioConfig::CHANNEL_LFE };
+      return config;
+    }
+    case 8: // the stream is 7.1 surround. channel order: front left, center, front right, side left, side right, rear left, rear right, LFE
+    {
+      static const Channel config[] = { AudioConfig::CHANNEL_LEFT, AudioConfig::CHANNEL_CENTER, AudioConfig::CHANNEL_RIGHT, AudioConfig::CHANNEL_LS, AudioConfig::CHANNEL_RS, AudioConfig::CHANNEL_RLS, AudioConfig::CHANNEL_RRS, AudioConfig::CHANNEL_LFE };
+      return config;
+    }
+    default:
+      return nullptr;
+  }
+}
 
 } // namespace mozilla
 #undef LOG

--- a/dom/media/platforms/agnostic/VorbisDecoder.h
+++ b/dom/media/platforms/agnostic/VorbisDecoder.h
@@ -3,16 +3,17 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #if !defined(VorbisDecoder_h_)
 #define VorbisDecoder_h_
 
 #include "PlatformDecoderModule.h"
 #include "mozilla/Maybe.h"
+#include "AudioConverter.h"
 
 #ifdef MOZ_TREMOR
 #include "tremor/ivorbiscodec.h"
 #else
 #include "vorbis/codec.h"
 #endif
 
 namespace mozilla {
@@ -32,16 +33,17 @@ public:
   nsresult Shutdown() override;
   const char* GetDescriptionName() const override
   {
     return "vorbis audio decoder";
   }
 
   // Return true if mimetype is Vorbis
   static bool IsVorbis(const nsACString& aMimeType);
+  static const AudioConfig::Channel* VorbisLayout(uint32_t aChannels);
 
 private:
   nsresult DecodeHeader(const unsigned char* aData, size_t aLength);
 
   void Decode (MediaRawData* aSample);
   int DoDecode (MediaRawData* aSample);
   void DoDrain ();
 
@@ -53,12 +55,13 @@ private:
   vorbis_info mVorbisInfo;
   vorbis_comment mVorbisComment;
   vorbis_dsp_state mVorbisDsp;
   vorbis_block mVorbisBlock;
 
   int64_t mPacketCount;
   int64_t mFrames;
   Maybe<int64_t> mLastFrameTime;
+  UniquePtr<AudioConverter> mAudioConverter;
 };
 
 } // namespace mozilla
 #endif