[Asterisk-Dev] RTP to IP Phone

[Steven Critchfield]

On Thu, 2005-12-15 at 07:41 -0800, ha i wrote:
> Hi Guys,
> 
> I am in the process of developing a soft phone that
> works with asterisk supported protocols. I need some
> help on decoding the ULAW RTP data for the client
> machine (laptop/desktop) speaker device. Like
> technology (Java Sound, JMF etc...) to use and
> encoding/decoding techniques for RTP data.
> 
> For example Xlite does very nice job converting ULAW
> data into Linear PCM. Obviously that code is not open
> source. So can you give me some pointers on where to
> look for???

Maybe you should look at code that does audio conversions like sox. Even
Asterisk has code that converts ulaw to 16bit PCM. Seems an odd question
with how many pieces of software exist that does such things.

Even worse, you mentioned wanting it in Java. The first google hit I see
for java sound conversion is
http://www.jsresources.org/examples/audio_conversion.html
Java Sound Resources: Examples: Audio Conversion
This page presents example that show how to encode audio data to ogg
vorbis, mp3, GSM 06.10 and mu-law and how to decode or play such files.
Additionally, sample rate conversion is demonstrated. The examples that
utilize the package javax.sound.sampled.

Too easy of a question for a developer list.

-- 
Steven Critchfield <critch at basesys.com>