Subject: Re: PCM8 vs. PCM16/LINEAR?
To: Timothy Newsham <>
From: Ignatios Souvatzis <>
List: tech-kern
Date: 08/03/1995 10:09:35
Hi Timothy,

> > >My working hypothesis has been:  PCM16/LINEAR is for 8- or 16-bit signed data;
> > >PCM8 is for 8-bit unsigned data.  There is no support for 16-bit
> > >unsigned data.  ULAW is for 8-bit Sun-style logarithmic encoding.  ALAW
> > >is for some format I haven't tackled yet.
> > 
> > Sun's audio(4) states that PCM data is always signed.  Either we
> > should define another symbol for unsigned data (e.g.
> > AUDIO_ENCODING_ULINEAR) or require that the hardware driver be

I second this, anyway.

> > responsible for any necessary conversion (may be SLOW).

Signed to unsigned linear or the other way round is quite fast.

> The amiga's native sound format is 8 bit unsigned.  It would

Last time I looked (5 seconds ago), the Amiga Hardware Reference Manual
(3rd edition, p.138) claimed it is 8 bit signed.