
Inter-region iLBC codec negotions
I am working through the lab and have set up Branch2 and CorpHQ region for the use of iLBC. I have set the link type to Lossy but still see G729 as the negotiated codec. Is this expected?
Mike
I am working through the lab and have set up Branch2 and CorpHQ region for the use of iLBC. I have set the link type to Lossy but still see G729 as the negotiated codec. Is this expected?
Mike
Comments
What Kind/Type of phones are you using? Do they support iLBC at all?
Best Regards,
Mike Lydick
7961 does not support iLBC.
Hi Mike,
if you are using the same phone as INE has on rack rentals, which is Cisco IP Phone 7961G, only support G711u and G729a as per the datasheet for this model. The iLBC on this example was asked only for configurations purpose. To test it you may use 7965G.
VoiceInsider
Kind Regards
On Apr 4, 2012, at 17:11, Voiceinsider <[email protected]> wrote:
The major advantage of iLBC codec is the fact that it allows a noticeable
improvement in voice quality especially in IP networks. Beside this fact, iLBC
is a free codec that means less costs in deployment than in case of other but
similar codecs. These issues make it possible to expand services and improve
quality easily and effectively.
iLBC is based on block independent linear predictive coding (LPC) algorithm.
The encoded blocks are encapsulated to be transported in a suitable protocol
like RTP.
iLBC has two supported bit rates. It operates at payload bit rate of 13,33 kbps (399 bits, packetized in 50
bytes) for the frame size of 30 ms and 15.2 kbps (303 bits, packetized in 38
bytes) for the frame size of 20 ms.
It is widely used and suitable especially for real time communication like
telephony, videoconferencing, streaming audio, messaging, archival.
iLBC is defined in RFC 3951. It is one of the codecs
used by Gizmo5, webRTC, Ekiga, QuteCom, Google Talk, Yahoo! Messenger, Polycom
IP Phone and Maemo Recorder (on the Nokia N800/N810) and many others.
Parameters and features:
·
Sampling frequency 8 kHz/16 bit (160 samples for 20 ms
frames, 240 samples for 30 ms frames)
·
Controlled response to packet loss, delay and jitter
·
Fixed bitrate (15.2 kbit/s for 20 ms frames, 13.33
kbit/s for 30 ms frames)
·
Fixed frame size (304 bits per block for 20 ms frames,
400 bits per block for 30 ms frames)
·
Robustness similar to pulse code modulation (PCM) with
packet loss concealment
·
CPU load with higher basic quality and better response
to packet loss
·
Computational complexity in a range of G.729A
·
Royalty Free Codec
For more info look at http://voip-sip-sdk.com/p_217-ilbc-codec-voip.html
Regards,
Niko