kiloohms 0 Posted February 1, 2014 I'm working on a VMS where it takes approx 30 secs (or more) for the VMS to detect a camera going offline and generate Video Loss Alarm. However, I believe this timing is more a Windows OS issue than the VMS. My theory is that Windows OS does not mark the TCP channel as closed/lost until after several keep-alives go un-responded and a certain time is elapsed afterwards. To support the theory, if I disable VMS computer's Network Card, Video Loss alarm happens pretty much within 10 sec; because the OS get to know its network capabilities are down before having to wait for keep-alive responses, etc. Is there a different explanation to above issue? Is it possible to tweak any setting to make VMS generate Video Loss Alarm quicker than 30 secs? Share this post Link to post Share on other sites
SunnyKim 2 Posted February 1, 2014 Kiloohms, If receiving side can parse the compress bit stream header, say HAL, the video loss can be detected and informed, earlier. Some may provide or some others may not depending on who they are, say text message for your phone. It all means Cost that you have to pay. And that's one of the disadvantages of the IP camera system in nature. But you do not worry about, as its recording has been made till the last frame of video loss. Share this post Link to post Share on other sites
kiloohms 0 Posted February 1, 2014 Kiloohms, If receiving side can parse the compress bit stream header, say HAL, the video loss can be detected and informed, earlier. Some may provide or some others may not depending on who they are, say text message for your phone. It all means Cost that you have to pay. And that's one of the disadvantages of the IP camera system in nature. But you do not worry about, as its recording has been made till the last frame of video loss. Thanks. I believe what you mean is if the VMS software uses its own method to detect loss of frames, it could do this faster but at a cost (both cpu cycles and money). And most rely on underlying OS to pass the link loss to VMS for it to consider a Video Loss event. By the way isn't it possible to tweak TCP parameters in the OS to make it detect link loss faster? Share this post Link to post Share on other sites
SunnyKim 2 Posted February 3, 2014 No idea on how VMS software is structured. But it is very true that IP cams can carry video loss information in the header of its compressed bit stream, as soon as video loss has been quickly detected. So you may consult with your solution provider. Share this post Link to post Share on other sites
kiloohms 0 Posted February 3, 2014 No idea on how VMS software is structured. But it is very true that IP cams can carry video loss information in the header of its compressed bit stream, as soon as video loss has been quickly detected. So you may consult with your solution provider. Thanks for the response. I'm concerned of video loss as a result of link fault where camera cannot send anything (unplugging the cable). Share this post Link to post Share on other sites
