--- a/dom/media/flac/FlacDemuxer.cpp
+++ b/dom/media/flac/FlacDemuxer.cpp
@@ -78,17 +78,17 @@ public:
     // Bits per sample.
     int bps_code = br.ReadBits(3);
     if (bps_code == 3 || bps_code == 7) {
       // Invalid sample size code.
       return false;
     }
     mInfo.mBitDepth = FlacSampleSizeTable[bps_code];
 
-    // Reserved bit, most be 1.
+    // Reserved bit, must be 0.
     if (br.ReadBit()) {
       // Broken stream, invalid padding.
       return false;
     }
 
     // Sample or frame count.
     int64_t frame_or_sample_num = br.ReadUTF8();
     if (frame_or_sample_num < 0) {