--- a/dom/media/platforms/agnostic/OpusDecoder.cpp
+++ b/dom/media/platforms/agnostic/OpusDecoder.cpp
@@ -98,20 +98,20 @@ OpusDataDecoder::DecodeHeader(const unsi
   MOZ_ASSERT(!mDecodedHeader);
   mDecodedHeader = true;
 
   mOpusParser = new OpusParser;
   if (!mOpusParser->DecodeHeader(const_cast<unsigned char*>(aData), aLength)) {
     return NS_ERROR_FAILURE;
   }
   int channels = mOpusParser->mChannels;
-  // No channel mapping for more than 8 channels.
-  if (channels > 8) {
-    OPUS_DEBUG("No channel mapping for more than 8 channels. Source is %d channels",
-               channels);
+
+  AudioConfig::ChannelLayout layout(channels);
+  if (!layout.IsValid()) {
+    OPUS_DEBUG("Invalid channel mapping. Source is %d channels", channels);
     return NS_ERROR_FAILURE;
   }
 
   AudioConfig::ChannelLayout vorbisLayout(
     channels, VorbisDataDecoder::VorbisLayout(channels));
   AudioConfig::ChannelLayout smpteLayout(channels);
   static_assert(sizeof(mOpusParser->mMappingTable) / sizeof(mOpusParser->mMappingTable[0]) >= MAX_AUDIO_CHANNELS,
                        "Invalid size set");