ORIGINAL decode.cpp

decode.cpp

@@ -0,0 +1,206 @@
+// SOURCE:
+// http://www.tinyted.net/eddie/decode.html
+
+struct VAGState
+{
+	VAGState()		{ Reset(); }
+
+	void	Reset()	{ s[0] = s[1] = 0; }
+
+	double	s[2];
+};
+
+void DecodeVAGBlock(const unsigned char in[16], short out[28], VAGState* state);
+
+const double filter[5][2] =
+{
+	{ 0.0, 0.0 },
+	{ 60.0 / 64.0,  0.0 },
+	{ 115.0 / 64.0, -52.0 / 64.0 },
+	{ 98.0 / 64.0, -55.0 / 64.0 },
+	{ 122.0 / 64.0, -60.0 / 64.0 }
+};
+
+const unsigned char	wavhdr[44] =
+{
+	'R','I','F','F',
+	0,0,0,0,			// length of file - 8
+	'W','A','V','E',
+
+	'f','m','t',' ',
+	0x10,0,0,0,
+	1,0,2,0,
+	0,0,0,0,			// sample rate
+	0,0xF4,1,0,
+	4,0,0x10,0,
+
+	'd','a','t','a',
+	0,0,0,0,			// length of file - 0x2C
+};
+
+int main(int argc, char *argv[])
+{
+	int		rate = 32000;
+
+	argc--;
+	argv++;
+
+	while (argc && (argv[0][0] == '-'))
+	{
+		char	parm = argv[0][1];
+
+		if (parm == 'r')
+		{
+			if (argv[0][2])
+			{
+				rate = atoi(argv[0] + 2);
+			}
+			else
+			{
+				argc--;
+				argv++;
+				rate = atoi(argv[0]);
+			}
+
+			printf("Sample rate : %d\n", rate);
+		}
+
+		argc--;
+		argv++;
+	}
+
+	char	src[256];
+	char	dst[256];
+
+	if (argc == 1)
+	{
+		sprintf(src, "%s.VB", argv[0]);
+		sprintf(dst, "%s.WAV", argv[0]);
+	}
+	else if (argc == 2)
+	{
+		strcpy(src, argv[0]);
+		strcpy(dst, argv[1]);
+	}
+	else
+	{
+		printf("Usage: Decode [-r <rate>] <in>|<root> [<out>]\n");
+		return -1;
+	}
+
+	FILE*	vag = fopen(src, "rb");
+	if (!vag)
+	{
+		printf("Can't open source file %s\n", src);
+		return -1;
+	}
+
+	// find number of blocks
+	fseek(vag, 0, SEEK_END);
+	int	length = ftell(vag) / 16;
+	fseek(vag, 0, SEEK_SET);
+
+	length /= 1024;
+
+	FILE*	wav = fopen(dst, "wb");
+	if (!wav)
+	{
+		printf("Can't open destination file %s\n", dst);
+		return -1;
+	}
+
+	printf("Length : %d blocks\n", length);
+
+	unsigned char	hdr[44];
+	int*			ihdr = (int*)hdr;
+
+	memcpy(hdr, wavhdr, 44);
+	ihdr[1] = length * 28 * 512 * 2 * 2 + 0x24;
+	ihdr[10] = length * 28 * 512 * 2 * 2;
+	ihdr[6] = rate;
+
+	fwrite(hdr, 1, 44, wav);
+
+	VAGState		st[2];
+	unsigned char	bl[512 * 16], br[512 * 16];
+	short			out[512 * 28 * 2];
+
+	for (int blk = 0; blk < length; blk++)
+	{
+		fread(bl, 16, 512, vag);
+		fread(br, 16, 512, vag);
+
+		for (int ii = 0; ii < 512; ii++)
+		{
+			short	obuf[28];
+
+			// decode left block
+			DecodeVAGBlock(bl + ii * 16, obuf, &st[0]);
+			for (int jj = 0; jj < 28; jj++)		out[(ii * 28 + jj) * 2] = obuf[jj];
+
+			// decode right block
+			DecodeVAGBlock(br + ii * 16, obuf, &st[1]);
+			for (int jj = 0; jj < 28; jj++)		out[(ii * 28 + jj) * 2 + 1] = obuf[jj];
+		}
+
+		// write output
+		fwrite(out, 2, 512 * 28 * 2, wav);
+	}
+
+	fclose(wav);
+	fclose(vag);
+
+	return 0;
+}
+
+int highnibble(int a)		{ return (a >> 4) & 15; }
+int lownibble(int a)		{ return a & 15; }
+
+short quantize(double sample)
+{
+	int a = int(sample + 0.5);
+
+	if (a < -32768) return -32768; 
+	if (a > 32767)	return 32767;
+
+	return short(a);
+}
+
+void DecodeVAGBlock(const unsigned char in[16], short out[28], VAGState* state)
+{
+	double	s[2];
+
+	s[0] = state->s[0];
+	s[1] = state->s[1];
+
+	int		predictor	= highnibble(in[0]);
+	int		shift		= lownibble(in[0]);
+	int		flags		= in[1];
+
+	if (predictor > 4)
+	{
+		// this should never happen in a valid VAG block
+		printf("Predictor %d!\n", predictor);
+		predictor = 0;
+	}
+
+	for (int ii = 0; ii < 14; ii++)
+	{
+		int	byte = in[ii + 2];
+
+		out[ii * 2]		= short(lownibble(byte) << 12)	>> shift;
+		out[ii * 2 + 1]	= short(highnibble(byte) << 12)	>> shift;
+	}
+
+	for (int ii = 0; ii < 28; ii++)
+	{
+		double filt = out[ii] + s[0] * filter[predictor][0] + s[1] * filter[predictor][1];
+		s[1] = s[0];
+		s[0] = filt;
+
+		out[ii] = quantize(filt);
+	}
+
+	state->s[0] = s[0];
+	state->s[1] = s[1];
+}