timing/clock source for video codecs

[chetankmaddela]

Hello All,

Is there any clock source (not NTP) which has to be setup in video codec, if not from where the codec will grab the timing ?

[Patrick Sparkman]

The codec will only receive time from NTP, otherwise it will use it's local internal clock which will eventually be incorrect.

If the codec is setup to use DHCP to obtain an IP address, it will ask the DHCP server what NTP serer to use, typically a domain controller on your network can provide the time.

If the codec is setup to use a static IP address, then the codec will use the manually entered NTP server in the codec's configuration, by default it is setup to resolve to an old TANBDERG NTP.  It's recommended that this be changed to an NTP server of your choice, you can use a domain controller if your environment has any, or any known reachable NTP server.

You didn't specify what type of codec this is in relation to, but the NTP settings are the same from codec to codec, so if you check this profile-c60-c40-and-codec-c60-c40-administrator-guide-tc70, pg 90, it describes NTP.

NTP can be configured via the web interface by going to Configuration > System Configuration > NetworkServices > NTP, or via command line through SSH by using xConfiguration NetworkServices NTP.

To check NTP status you can do it via the web interface by going to Configuration > System Status > Network Services NTP, or via command line through SSH by using SystemTools NTP.

[chetankmaddela]

Hi Patrick,

Thanks for your reply,

Sorry if my question was brief.. 

We are facing jitter issue in our video call, jitter is normally relates to a timing/clock source, in this instance if a call is happening between A and B we can conclude that Master clock will be source and slave clock will be destination.

We want to track down what timing/clock source is followed by video codec (mostly C20, SX 20 codecs) when call is running.

For NTP we have changed all NTP settings in device and those are pointed to our NTP server, this works fine.

--

Thanks

Chetan

[Chris Swinney]

Hi Chetan,

I have to ask, did setting the NTP server on the CODEC resolve this issue? If not, you may find that jitter can be caused by other factors relating to your network.

Cheers

Chris