1 files changed, 171 insertions, 0 deletions
diff --git a/pjmedia/src/pjmedia-audiodev/s60_g729_bitstream.h b/pjmedia/src/pjmedia-audiodev/s60_g729_bitstream.h
new file mode 100644
index 00000000..ae13bb11
--- /dev/null
+++ b/pjmedia/src/pjmedia-audiodev/s60_g729_bitstream.h
@@ -0,0 +1,171 @@
+#ifndef __BITSTREAM_H_
+#define __BITSTREAM_H_
+
+#define KPackedFrameLen 10
+#define KUnpackedFrameLen 22
+
+// Below values are taken from the APS design document
+const TUint8 KG729FullPayloadBits[] = { 8, 10, 8, 1, 13, 4, 7, 5, 13, 4, 7 };
+const TUint  KNumFullFrameParams = 11;
+const TUint8 KG729SIDPayloadBits[] = { 1, 5, 4, 5 };
+const TUint  KNumSIDFrameParams = 4;
+
+/*! 
+  @class TBitStream
+  
+  @discussion Provides compression from 16-bit-word-aligned G.729 audio frames
+  (used in S60 G.729 DSP codec) to 8-bit stream, and vice versa.
+  */
+class TBitStream
+  {        
+public:
+    /*!
+      @function TBitStream
+      
+      @discussion Constructor
+      */   
+    TBitStream():iDes(iData,KUnpackedFrameLen){}
+    /*!
+      @function CompressG729Frame
+      
+      @discussion Compress either a 22-byte G.729 full rate frame to 10 bytes
+      or a 8-byte G.729 Annex.B SID frame to 2 bytes.
+      @param aSrc Reference to the uncompressed source frame data
+      @param aIsSIDFrame True if the source is a SID frame
+      @result a reference to the compressed frame
+      */
+    const TDesC8& CompressG729Frame( const TDesC8& aSrc, TBool aIsSIDFrame = EFalse );
+    
+    /*!
+      @function ExpandG729Frame
+            
+      @discussion Expand a 10-byte G.729 full rate frame to 22 bytes
+      or a 2-byte G.729 Annex.B SID frame to 8(22) bytes.
+      @param aSrc Reference to the compressed source frame data
+      @param aIsSIDFrame True if the source is a SID frame
+      @result a reference to a descriptor representing the uncompressed frame.
+      Note that SID frames are zero-padded to 22 bytes as well.
+      */
+    const TDesC8& ExpandG729Frame( const TDesC8& aSrc, TBool aIsSIDFrame = EFalse );
+
+private:
+    void Compress( TUint8 aValue, TUint8 aNumOfBits );
+    void Expand( const TUint8* aSrc, TInt aDstIdx, TUint8 aNumOfBits );
+
+private:
+    TUint8      iData[KUnpackedFrameLen];
+    TPtr8       iDes;
+    TInt        iIdx;
+    TInt        iBitOffset;
+    };
+    
+
+const TDesC8& TBitStream::CompressG729Frame( const TDesC8& aSrc, TBool aIsSIDFrame )
+    {
+    // reset data
+    iDes.FillZ(iDes.MaxLength());
+    iIdx = iBitOffset = 0;
+    
+    TInt numParams = (aIsSIDFrame) ? KNumSIDFrameParams : KNumFullFrameParams;
+    const TUint8* p = const_cast<TUint8*>(aSrc.Ptr());
+    
+    for(TInt i = 0, pIdx = 0; i < numParams; i++, pIdx += 2) 
+        {
+        TUint8 paramBits = (aIsSIDFrame) ? KG729SIDPayloadBits[i] : KG729FullPayloadBits[i];        
+        if(paramBits > 8)
+            {
+            Compress(p[pIdx+1], paramBits - 8); // msb
+            paramBits = 8;
+            }            
+        Compress(p[pIdx], paramBits); // lsb    
+        }
+
+    if( iBitOffset )
+        iIdx++;
+        
+    iDes.SetLength(iIdx);
+    return iDes;
+    }
+
+ 
+const TDesC8& TBitStream::ExpandG729Frame( const TDesC8& aSrc, TBool aIsSIDFrame )
+    {
+    // reset data
+    iDes.FillZ(iDes.MaxLength());
+    iIdx = iBitOffset = 0;
+    
+    TInt numParams = (aIsSIDFrame) ? KNumSIDFrameParams : KNumFullFrameParams;
+    const TUint8* p = const_cast<TUint8*>(aSrc.Ptr());
+    
+    for(TInt i = 0, dIdx = 0; i < numParams; i++, dIdx += 2) 
+        {
+        TUint8 paramBits = (aIsSIDFrame) ? KG729SIDPayloadBits[i] : KG729FullPayloadBits[i];
+        if(paramBits > 8)
+          {
+          Expand(p, dIdx+1, paramBits - 8); // msb
+          paramBits = 8;
+          }    
+        Expand(p, dIdx, paramBits); // lsb 
+        }
+        
+    iDes.SetLength(KUnpackedFrameLen);
+    return iDes;
+    }
+
+
+void TBitStream::Compress( TUint8 aValue, TUint8 aNumOfBits )
+  {
+    // clear bits that will be discarded
+    aValue &= (0xff >> (8 - aNumOfBits));
+    
+    // calculate required bitwise left shift
+    TInt shl = 8 - (iBitOffset + aNumOfBits);
+    
+    if (shl == 0) // no shift required
+        { 
+        iData[iIdx++] |= aValue;
+        iBitOffset = 0;
+        }
+    else if (shl > 0) // bits fit into current byte
+        { 
+        iData[iIdx] |= (aValue << shl);
+        iBitOffset += aNumOfBits;
+        }        
+    else        
+        { 
+        iBitOffset = -shl;
+        iData[iIdx] |= (aValue >> iBitOffset); // right shift
+        iData[++iIdx] |= (aValue << (8-iBitOffset)); // push remaining bits to next byte
+        }
+  }
+    
+
+void TBitStream::Expand( const TUint8* aSrc, TInt aDstIdx, TUint8 aNumOfBits )
+  {    
+    TUint8 aValue = aSrc[iIdx] & (0xff >> iBitOffset);
+       
+    // calculate required bitwise right shift
+    TInt shr = 8 - (iBitOffset + aNumOfBits);
+    
+    if (shr == 0) // no shift required
+        { 
+        iData[aDstIdx] = aValue;
+        iIdx++;
+        iBitOffset = 0;
+        }
+    else if (shr > 0) // right shift
+        { 
+        iData[aDstIdx] = (aValue >> shr);
+        iBitOffset += aNumOfBits;
+        }        
+    else // shift left and take remaining bits from the next src byte
+        {
+        iBitOffset = -shr;
+        iData[aDstIdx] = aValue << iBitOffset;                
+        iData[aDstIdx] |= aSrc[++iIdx] >> (8 - iBitOffset);
+        }
+  }
+
+#endif // __BITSTREAM_H_
+    
+// eof