diff --git a/Source/Core/Core/HW/DVD/DVDInterface.cpp b/Source/Core/Core/HW/DVD/DVDInterface.cpp
index b7d897fdbc..7d94579e75 100644
--- a/Source/Core/Core/HW/DVD/DVDInterface.cpp
+++ b/Source/Core/Core/HW/DVD/DVDInterface.cpp
@@ -207,6 +207,8 @@ static UDICR s_DICR;
 static UDIIMMBUF s_DIIMMBUF;
 static UDICFG s_DICFG;
 
+static StreamADPCM::ADPCMDecoder s_adpcm_decoder;
+
 // DTK
 static bool s_stream = false;
 static bool s_stop_at_track_end = false;
@@ -286,7 +288,7 @@ void DoState(PointerWrap& p)
 
   DVDThread::DoState(p);
 
-  StreamADPCM::DoState(p);
+  s_adpcm_decoder.DoState(p);
 }
 
 static size_t ProcessDTKSamples(std::vector<s16>* temp_pcm, const std::vector<u8>& audio_data)
@@ -295,7 +297,7 @@ static size_t ProcessDTKSamples(std::vector<s16>* temp_pcm, const std::vector<u8
   size_t bytes_processed = 0;
   while (samples_processed < temp_pcm->size() / 2 && bytes_processed < audio_data.size())
   {
-    StreamADPCM::DecodeBlock(&(*temp_pcm)[samples_processed * 2], &audio_data[bytes_processed]);
+    s_adpcm_decoder.DecodeBlock(&(*temp_pcm)[samples_processed * 2], &audio_data[bytes_processed]);
     for (size_t i = 0; i < StreamADPCM::SAMPLES_PER_BLOCK * 2; ++i)
     {
       // TODO: Fix the mixer so it can accept non-byte-swapped samples.
@@ -331,7 +333,7 @@ static u32 AdvanceDTK(u32 maximum_samples, u32* samples_to_process)
         break;
       }
 
-      StreamADPCM::InitFilter();
+      s_adpcm_decoder.ResetFilter();
     }
 
     s_audio_position += StreamADPCM::ONE_BLOCK_SIZE;
@@ -933,7 +935,7 @@ void ExecuteCommand(u32 command_0, u32 command_1, u32 command_2, u32 output_addr
           s_current_start = s_next_start;
           s_current_length = s_next_length;
           s_audio_position = s_current_start;
-          StreamADPCM::InitFilter();
+          s_adpcm_decoder.ResetFilter();
           s_stream = true;
         }
       }
diff --git a/Source/Core/Core/HW/StreamADPCM.cpp b/Source/Core/Core/HW/StreamADPCM.cpp
index 1175eb8c9c..fe309b63a5 100644
--- a/Source/Core/Core/HW/StreamADPCM.cpp
+++ b/Source/Core/Core/HW/StreamADPCM.cpp
@@ -12,12 +12,6 @@
 
 namespace StreamADPCM
 {
-// STATE_TO_SAVE
-static s32 histl1;
-static s32 histl2;
-static s32 histr1;
-static s32 histr2;
-
 static s16 ADPDecodeSample(s32 bits, s32 q, s32& hist1, s32& hist2)
 {
   s32 hist = 0;
@@ -49,30 +43,30 @@ static s16 ADPDecodeSample(s32 bits, s32 q, s32& hist1, s32& hist2)
   return (s16)cur;
 }
 
-void InitFilter()
+void ADPCMDecoder::ResetFilter()
 {
-  histl1 = 0;
-  histl2 = 0;
-  histr1 = 0;
-  histr2 = 0;
+  m_histl1 = 0;
+  m_histl2 = 0;
+  m_histr1 = 0;
+  m_histr2 = 0;
 }
 
-void DoState(PointerWrap& p)
+void ADPCMDecoder::DoState(PointerWrap& p)
 {
-  p.Do(histl1);
-  p.Do(histl2);
-  p.Do(histr1);
-  p.Do(histr2);
+  p.Do(m_histl1);
+  p.Do(m_histl2);
+  p.Do(m_histr1);
+  p.Do(m_histr2);
 }
 
-void DecodeBlock(s16* pcm, const u8* adpcm)
+void ADPCMDecoder::DecodeBlock(s16* pcm, const u8* adpcm)
 {
   for (int i = 0; i < SAMPLES_PER_BLOCK; i++)
   {
     pcm[i * 2] = ADPDecodeSample(adpcm[i + (ONE_BLOCK_SIZE - SAMPLES_PER_BLOCK)] & 0xf, adpcm[0],
-                                 histl1, histl2);
+                                 m_histl1, m_histl2);
     pcm[i * 2 + 1] = ADPDecodeSample(adpcm[i + (ONE_BLOCK_SIZE - SAMPLES_PER_BLOCK)] >> 4, adpcm[1],
-                                     histr1, histr2);
+                                     m_histr1, m_histr2);
   }
 }
 }
diff --git a/Source/Core/Core/HW/StreamADPCM.h b/Source/Core/Core/HW/StreamADPCM.h
index 7ec6022137..e960a0a60e 100644
--- a/Source/Core/Core/HW/StreamADPCM.h
+++ b/Source/Core/Core/HW/StreamADPCM.h
@@ -18,7 +18,17 @@ enum
   SAMPLES_PER_BLOCK = 28
 };
 
-void InitFilter();
-void DoState(PointerWrap& p);
-void DecodeBlock(s16* pcm, const u8* adpcm);
+class ADPCMDecoder
+{
+public:
+  void ResetFilter();
+  void DoState(PointerWrap& p);
+  void DecodeBlock(s16* pcm, const u8* adpcm);
+
+private:
+  s32 m_histl1 = 0;
+  s32 m_histl2 = 0;
+  s32 m_histr1 = 0;
+  s32 m_histr2 = 0;
+};
 }