Embedded IP Cameras dont typically have a hardware Real Time Clock to help it track time, instead it uses processing cycles to calculate time and this can vary depending on voltages, temperatures, etc and quickly get out of sync with reality.. even if it does have a hardware RTC it will need a battery backup to keep time after a power loss and even a highly accurate one will drift off time a noticeable amount after a year.
To Combat this IPCameras sync time via the Network Time Protocol (NTP)
If you have one or two cameras, or your NVR is overlaying timestamps your best bet is to use a NTP Pool that is always available and nearby.. I would avoid using Microsoft or Apple's servers, many networks hijack there addresses and redirect them to an internal NTP server.. I do it so all machines sync time off my local NTP service without reconfiguring all the workstations.. you never know where you'll end up.
If you have more than a few cameras you should choose a singular server for all of them, because the pool could give each camera a different server and this could result in some being slightly off from others... here is a nice list of individual US Based servers, I am lucky with alot of these being in Colorado I get a ping less than 10ms on many of these..
And the best option IMHO would be run your own NTP Server on your NVR or Router, or any machine on your network that is always on and reliable.. If your running DD/Open-WRT it should be easy to do on your router, google it.
The benefit of this is you can sync your cameras as quickly as they can (its abusive to do that to someone else's NTP server, if its not your server once every 20mins is more than enough) and the local network latency and throughput is much better than the internet's, if your internet has an outage you know everything is keeping correct time based off your NTPD running off a PC that has a more accurate RTC, with a battery to keep time when there is no power.. Of course your NTP Server needs to sync time with an upstream server or a radio signal every once and a while.
If your running NTPd by default your NTP server will deny requests from other machines on your local network, we want to change that and it requires adding a line such as this to the configuration: (if your running a software firewall you may need to open UDP Port 123)
It will also use a default set of pool servers, feel free to change that but you want to keep several in there for it to compare latency with.
If your running a stand-alone IPCam network that is not hooked to the internet I would suggest running a NTPd and hooking up a cheap USB GPS Dongle in a nearby window.. this will give you an atomic time sync without requiring internet access.
A RasberyPI with a RTC Add-on and a GPS Receiver would make a pretty awesome lil personal NTP Server and could be considered more accurate than syncing from any internet server.: http://afterthoughtsoftware.com/products/rasclock
If your camera footage is ever required for a criminal investigation having all your timestamps as accurate as possible will help alot, if your times are unreliable then the timestamps are basically worthless and not trustworthy.
Dont forget to setup your DST Settings!
To Combat this IPCameras sync time via the Network Time Protocol (NTP)
If you have one or two cameras, or your NVR is overlaying timestamps your best bet is to use a NTP Pool that is always available and nearby.. I would avoid using Microsoft or Apple's servers, many networks hijack there addresses and redirect them to an internal NTP server.. I do it so all machines sync time off my local NTP service without reconfiguring all the workstations.. you never know where you'll end up.
[*=1]north-america.pool.ntp.org
[*=1]europe.pool.ntp.org
[*=1]asia.pool.ntp.org
[*=1]africa.pool.ntp.org
[*=1]oceania.pool.ntp.org
[*=1]south-america.pool.ntp.org
[*=1]more info on NTP pools: http://www.pool.ntp.org/
If you have more than a few cameras you should choose a singular server for all of them, because the pool could give each camera a different server and this could result in some being slightly off from others... here is a nice list of individual US Based servers, I am lucky with alot of these being in Colorado I get a ping less than 10ms on many of these..
[*=1]NIST Government NTP Servers: http://tf.nist.gov/tf-cgi/servers.cgi
And the best option IMHO would be run your own NTP Server on your NVR or Router, or any machine on your network that is always on and reliable.. If your running DD/Open-WRT it should be easy to do on your router, google it.
The benefit of this is you can sync your cameras as quickly as they can (its abusive to do that to someone else's NTP server, if its not your server once every 20mins is more than enough) and the local network latency and throughput is much better than the internet's, if your internet has an outage you know everything is keeping correct time based off your NTPD running off a PC that has a more accurate RTC, with a battery to keep time when there is no power.. Of course your NTP Server needs to sync time with an upstream server or a radio signal every once and a while.
[*=1]More Info: http://en.wikipedia.org/wiki/Ntpd
[*=1]Windows NetTime Software, Very Easy w/GUI: http://www.timesynctool.com/
If your running NTPd by default your NTP server will deny requests from other machines on your local network, we want to change that and it requires adding a line such as this to the configuration: (if your running a software firewall you may need to open UDP Port 123)
Code:
[COLOR=#000000][FONT=monospace]restrict 192.168.0.0 mask 255.255.0.0 nomodify notrap[/FONT][/COLOR]If your running a stand-alone IPCam network that is not hooked to the internet I would suggest running a NTPd and hooking up a cheap USB GPS Dongle in a nearby window.. this will give you an atomic time sync without requiring internet access.
A RasberyPI with a RTC Add-on and a GPS Receiver would make a pretty awesome lil personal NTP Server and could be considered more accurate than syncing from any internet server.: http://afterthoughtsoftware.com/products/rasclock
If your camera footage is ever required for a criminal investigation having all your timestamps as accurate as possible will help alot, if your times are unreliable then the timestamps are basically worthless and not trustworthy.
Dont forget to setup your DST Settings!
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