Hi,
I'd like to present yet another small PJSIP based application - network
emulator. I hope this will be interesting for somebody here.
Network emulator is an utility intended for modelling of proccesses in
real IP-telephony networks. Its core features has been implemented with
PJMEDIA library.
This utility implemented within a research work. One of the goal of this
work and the main purpose of the utility is to measure speech quality
depending on different encoding parameters and channel impacts.
Emulator can help quickly obtain these measures:
- compare encoding quality for different codecs and codecs modes.
- estimate the impact of the loss level and distribution on the speech
quality.
- estimate the impact of the different PLC algorithms on the speech
quality.
Quality estimation may be carried out subjectively but it's better to
use automatic tests such as PESQ (reference implementation can be found
here [1]). Network emulator helps to obtain reference and degraded
speech samples.
Utility features and drawbacks:
- Quite limited channel model (with losses and bandwidth only). However
as experiments shows, this one reflects real channel properties good
enough.
- Lack of the module for delays and jitter-buffer to compensate this.
Source code can be downloaded from the project page located on the
github [2]
I'll be glad to answer to criticisms and questions if someone find this
utility useful and allot his time to comment this work.
[1]: http://www.itu.int/rec/T-REC-P.862/en
[2]: http://github.com/imankulov/network-emulator/
--
Roman Imankulov
roman at netangels.ru
