[asterisk-dev] downsampling slinear16 to ulaw (or alaw or g729)

[Paul Albrecht]

On Mon, 2010-08-30 at 10:02 -0500, Kevin P. Fleming wrote:
> On 08/30/2010 09:39 AM, Paul Albrecht wrote:
> 
> > I have a question about asterisk transcoding from wide slinear to ulaw
> > (or alaw or g729). Specifically, the result I get when I translate from
> > AST_FORMAT_SLINEAR16 to AST_FORMAT_ULAW is truncated, that is, I don't
> > get a 160 samples in the output frame. Is this a bug or should I have
> > expected the translator to truncate the result?
> 
> How many samples were in the input frame? Is there a smoother involved?
> 

The slinear16 frame contains 320 samples and I'm getting 137 samples of
ulaw out which is not what I expected. I was looking for a full 160
samples of ulaw.

I don't know if a smoother was involved. Here's how I do the
translation:

trans = ast_translate_build_path(AST_FORMAT_ULAW,AST_FORMAT_SLINEAR16);
out = ast_translate(trans,in,0)


> -- 
> Kevin P. Fleming
> Digium, Inc. | Director of Software Technologies
> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
> skype: kpfleming | jabber: kfleming at digium.com
> Check us out at www.digium.com & www.asterisk.org
> 
-- 
Paul Albrecht