[maemo-developers] Proof of concept G.711 dsptask

[From: Simon Pickering]

Hello all,

I've created a quick proof of concept dsp task that should perform 
pcm->ulaw encoding. I say should as I've only quickly inspected the 
first few hundred bytes of the each file using a hexeditor so there 
might be discrepancies later on.

Code and instructions here: 
http://people.bath.ac.uk/enpsgp/nokia770/dsp/G.711/

I didn't need to do much, I simply took the guts of the COSTG711.tar.gz 
package and placed it in a dsp task. Luckily this only needs to look at 
shorts (which means the odd >2byte endianness of the DSP doesn't come 
into play), but it does deal with 8bit chars (chars on the DSP are 
16bit) so I did a bit of OR'ing to produce the expected output.

I chose something relatively easy to make sure I didn't lose the will 
(battling against both the algorithm and the DSP oddities).

Anyway, my hope is that this might show people that it's quite easy to 
use the dsp (for something simple at least), and to get people thinking 
of other ways of using it.

Have a nice weekend all,

Cheers,


Simon