Question about 16-bit waveform audio data

[Leroy1981]

I can convert an 8-bit audio sample to an int no problem.
But I store the wave data in an array of BYTEs so a 16-bit
sample consists of 2 separate BYTEs. I tried to take these
BYTEs and memcpy them into a WORD since it's the same size as the two and cast it to int but I get values like 64,292
when the values should range between -128 and 128. Can anyone please help me. When I convert 8-bit sound to 16-bit I use memcpy as said above and everything works fine.

 

[Totte]

Hi.

64,292 is hex FB24 and if you uses the values SIGNED in stead of unsigned then you will see that it's really -1243 and not 64292........

memcpy works real good even with integers (signed/unsigned) but sometimes it's the interpetation of the values that messes up things.

Totte
Keep making it perfect and it will end up broken.

 

[Supernat03]

Can you post the code? Instead of using memcpy, you could also bitwise OR them.

int x=0;

x = (int)((unsigned short int)byte1 | (((unsigned short int)byte2) << 8));

This produces a word from two bytes, then casts it to an int.

Chris

 

[Totte]

By the way:
union
{
BYTE DataB[BIG!];
int DataI[half_as_BIG!];
} Soundtabel;

Lets you access it as bytes (Soundtabel.DataB[]) or as integers (Soundtabel.DataI[]) as you wish.

Or:

BYTE * TabelB;
int * TabelI;
TabelB = new BYTE[BIG_NUMBER];
TabelI = (int*)TabelB;

Now they point on the same datas and is BYTEs and Integers.

Totte
Keep making it perfect and it will end up broken.