PCMA codec - Sound quality improved

Bug correction.
Remove alaw header from git repository.
Add GPL license in ulaw.cpp

src/audio/alaw.cpp

@@ -23,100 +23,98 @@
 
 class Alaw : public AudioCodec {
 public:
-
-// 8 PCMA A 8000 1 [RFC3551]
-   Alaw(int payload=0)
- : AudioCodec(payload, "PCMA")
-{
-  //_description = "G711a";
-
-  _clockRate = 8000;
-  _channel   = 1;
-}
-
-
-virtual int codecDecode (short *dst, unsigned char *src, unsigned int size) 
-{
-	int16* end = dst+size;
-        while(dst<end)
-                *dst++ = ALawDecode(*src++);
-        return size<<1;
-}
-
-int ALawDecode(uint8 alaw)
-{
-	alaw ^= 0x55;  // A-law has alternate bits inverted for transmission
-
-        uint sign = alaw&0x80;
-
-        int linear = alaw&0x1f;
-        linear <<= 4;
-	linear += 8;  // Add a 'half' bit (0x08) to place PCM value in middle of range
-
-        alaw &= 0x7f;
-        if(alaw>=0x20)
-        {
-        	linear |= 0x100;  // Put in MSB
-		uint shift = (alaw>>4)-1;
-                linear <<= shift;
-        }
-
-        if(!sign)
-                return -linear;
-        else
-                return linear;
-}
-
-virtual int codecEncode (unsigned char *dst, short *src, unsigned int size) 
-{	
-	size >>= 1;
-        uint8* end = dst+size;
-        while(dst<end)
-                *dst++ = ALawEncode(*src++);
-        return size;
-}
-
-
-uint8 ALawEncode (int16 pcm16)
-{
-	int p = pcm16;
-        uint u;  // u-law value we are forming
-
-        if(p<0)
-        {
-	p = ~p;
-                u = 0x80^0x10^0xff;  // Sign bit = 1 (^0x10 because this will get inverted later) ^0xff ^0xff to invert final u-Law code
-                }
-        else
-                {
-	//+ve value
-	u = 0x00^0x10^0xff;	
- }
-
-        p += 0x84; // Add uLaw bias
-
-        if(p>0x7f00)
-                p = 0x7f00;  // Clip to 15 bits
-	p >>= 3;        // Shift down to 13bit
-        if(p>=0x100)
+    // 8 PCMA A 8000 1 [RFC3551]
+   	Alaw(int payload=0)
+ 	: AudioCodec(payload, "PCMA")
+	{
+  		_clockRate = 8000;
+  		_channel   = 1;
+	}
+
+
+	virtual int codecDecode (short *dst, unsigned char *src, unsigned int size) 
+	{
+		int16* end = dst+size;
+        	while(dst<end)
+                	*dst++ = ALawDecode(*src++);
+        	return size<<1;
+	}
+
+	virtual int codecEncode (unsigned char *dst, short *src, unsigned int size) 
+	{	
+		size >>= 1;
+        	uint8* end = dst+size;
+        	while(dst<end)
+                	*dst++ = ALawEncode(*src++);
+        	return size;
+	}
+
+
+
+	int ALawDecode(uint8 alaw)
+	{
+		alaw ^= 0x55;  // A-law has alternate bits inverted for transmission
+        	uint sign = alaw&0x80;
+        	int linear = alaw&0x1f;
+        	linear <<= 4;
+		linear += 8;  // Add a 'half' bit (0x08) to place PCM value in middle of range
+
+        	alaw &= 0x7f;
+        	if(alaw>=0x20)
+        	{
+        		linear |= 0x100;  // Put in MSB
+			uint shift = (alaw>>4)-1;
+                	linear <<= shift;
+        	}
+
+       	 	if(!sign)
+                	return -linear;
+        	else
+                	return linear;
+	}
+
+
+	uint8 ALawEncode (int16 pcm16)
+	{
+		int p = pcm16;
+        	uint a;  // u-law value we are forming
+
+        	if(p<0)
+        	{
+			p = ~p;
+			 a = 0x00; // sign = 0
+		}
+		else
+		{
+			//+ve value
+			a = 0x80; //sign = 1
+		}
+		//calculate segment and interval numbers
+		 p >>= 4;
+        	if(p>=0x20)
                 {
-                p >>= 4;
-                u ^= 0x40;
+                	if(p>=0x100)
+                        {
+                        	p >>= 4;
+                        	a += 0x40;
+                        }
+                	if(p>=0x40)
+                        {
+                        	p >>= 2;
+                        	a += 0x20;
+                        }
+                	if(p>=0x20)
+                        {
+                        	p >>= 1;
+                        	a += 0x10;
+                        }
                 }
-        if(p>=0x40)
-                {
-                p >>= 2;
-                u ^= 0x20;
-                }
-        if(p>=0x20)
-                {
-                p >>= 1;
-                u ^= 0x10;
-                }
-	u ^= p; // u now equal to encoded u-law value (with all bits inverted)
+	// a&0x70 now holds segment value and 'p' the interval number
+	a += p; // a now equal to encoded A-law value
+
+	return a^0x55; // A-law has alternate bits inverted for transmission
+	}
 
-        return u;
-}
 };
 
 // the class factories

src/audio/alaw.h

-/*
- *  Copyright (C) 2004-2005-2006 Savoir-Faire Linux inc.
- *  Author:  Yan Morin <yan.morin@savoirfairelinux.com>
- *  Author:  Laurielle Lea <laurielle.lea@savoirfairelinux.com>
- *                                                                              
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *                                                                              
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-#ifndef __ALAW_H__
-#define __ALAW_H__
-
-#include "audiocodec.h"
-
-/**
- * Alaw audio codec (payload is 8)
- */
-class Alaw : public AudioCodec {
-public:
-  // payload should be 8
-	Alaw (int payload=8);
-	~Alaw (void);
-	
-	int	codecDecode	(short *, unsigned char *, unsigned int);
-	int	codecEncode	(unsigned char *, short *, unsigned int);
-        void test () ;
-};
-
-#endif // __ULAW_H__

src/audio/ulaw.cpp

+/**
+ * Copyright (C) 2004-2005 Savoir-Faire Linux inc.
+ * Author:  Yan Morin <yan.morin@savoirfairelinux.com>
+ * Author:  Laurielle Lea <laurielle.lea@savoirfairelinux.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *                                                                              
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ **/
+
+
+
 #include "common.h"
 #include "audiocodec.h"
 
@@ -11,7 +33,6 @@ public:
   		_channel   = 1;
 	}
 
-
 	virtual int codecDecode (short *dst, unsigned char *src, unsigned int size) {
 		int16* end = dst+size;
         	while(dst<end)