DesignAEC

Version 26 (Adrian Georgescu, 07/10/2013 07:03 am)

1 23 Adrian Georgescu
h1. Acoustic Echo cancellation
2 1 Adrian Georgescu
3 26 Adrian Georgescu
h2. This project has been canned. the AEC has ben replaced with WebRTC AEC.
4 23 Adrian Georgescu
5 1 Adrian Georgescu
SIP SIMPLE client is a Python software library that allows for easy development of Internet communications end-points based on SIP and related protocols for voice, rich presence, session based instant messaging (IM), file transfers and desktop sharing. Other media types can be easily added by using an extensible high-level API. SIP SIMPLE client uses "PJSIP media library":http://www.pjsip.org/pjmedia/docs/html/index.htm for audio processing (sound card abstraction, audio codec and acoustic echo cancellation).
6 23 Adrian Georgescu
7 26 Adrian Georgescu
For more information see http://sipsimpleclient.org. The project is maintained by AG Projects that can provide help to the developer to integrate its AEC implementation.
8 1 Adrian Georgescu
9 1 Adrian Georgescu
10 23 Adrian Georgescu
h2. Background
11 23 Adrian Georgescu
12 23 Adrian Georgescu
13 1 Adrian Georgescu
The present implementation of the Acoustic Echo Canceller from PJSIP media library is not performing to the desired level of quality. Practically, the speakerphone function is not performing satisfactory. The result is that the software phone cannot be used without a head-set, which make people use proprietary applications like Skype or Google Talk.
14 1 Adrian Georgescu
15 24 Tijmen de Mes
!http://www.pjsip.org/images/media-flow.jpg!
16 1 Adrian Georgescu
17 1 Adrian Georgescu
18 23 Adrian Georgescu
h2. Project goal
19 23 Adrian Georgescu
20 23 Adrian Georgescu
21 1 Adrian Georgescu
Replace the existing AEC from Pjmedia library based on speex  (what is displayed as echo.h in the above diagram whihc employes the AEC of the speex project) with Andree Adrian AEC implementation now available in Pulse Audio server. 
22 1 Adrian Georgescu
23 1 Adrian Georgescu
24 23 Adrian Georgescu
h2. PJMEDIA
25 7 Adrian Georgescu
26 23 Adrian Georgescu
27 23 Adrian Georgescu
* PJSIP media library http://pjsip.org, used by this project, AEC is implemented based on the Speex library, the code in pjsip/pjmedia/src/pjmedia/echo_speex.c 
28 23 Adrian Georgescu
* Media flow - http://trac.pjsip.org/repos/wiki/media-flow
29 23 Adrian Georgescu
* PJSIP AEC API http://www.pjsip.org/pjmedia/docs/html/group+PJMEDIA+Echo+Cancel.htm
30 23 Adrian Georgescu
31 23 Adrian Georgescu
32 23 Adrian Georgescu
h3. Andree Adrian AEC
33 23 Adrian Georgescu
34 21 Adrian Georgescu
35 22 Adrian Georgescu
PulseAudio contain this echo canceler re-written in C in latest git repository in src/modules/echo-canceller/
36 22 Adrian Georgescu
37 1 Adrian Georgescu
A previous attempt to integrated this echo-canceler, is attached. It should be used just for an example of integrating a new canceler into pjmedia, the actual code should be taken from pulse audio.