james.wilson Posted September 13, 2011 Author Posted September 13, 2011 problem is d1 at a sh1te bitrate is worse then cif. also some dvr's dont tell the truth about their actual framerate, and lets be honest how would an installer test. You select 12 fps you assume thats what its doing. It can be tested but not easily, id be curious to know how many installers do actually check the claims. securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount.
fozzies Posted September 13, 2011 Posted September 13, 2011 Surely d1 is the best record level possible? cant say ive ever seen cif better , cif is something like 320* 200 pixels, whereas d1 is 720*480 ish. thats something like 4 times the quality( hope my maths hasnt let me down here). I guess there may be some compression that could destroy that quality, but uncompressed d1 has to be king. i guess it entirely depends on the dvr in question
james.wilson Posted September 13, 2011 Author Posted September 13, 2011 id agree but a lot of dvr's have a limited max bi rate. They look great live but movement causes artefacts that on the cheap units are worse then recording at cif. its not as simple as resolution. Its like comparing engine sizes. some have more power than others you cant compare on specs alone without being aware of the things the specs dont tell you. h264 is a complicated recording system. Its not just about res and framerate. I have done some research on it and you can see that on a review i did here. Your final comment is bang on though ie it depends on the dvr and all the factors that go into it. It may run constant bit rate, it may run variable bit rate. You need to know it upper limit on bitrate and wether its hard ware or software etc. a member here digital witness knows far more on this than i do. securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount.
fozzies Posted September 13, 2011 Posted September 13, 2011 I guess the moral here is to ignore the £500 hbl specials and stick to dm etc. Only time ive ever seen any bad d1 recordings is when i was once called in to comment on a "professional"instalation, but that dvr had chinese hyroglyphics on the front of it!
james.wilson Posted September 13, 2011 Author Posted September 13, 2011 its not just dm, there are some units that dont have a main brand name that can out perform the dm. But most of them are shockingly bad imo. but look good on specs securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount.
jnealon Posted September 14, 2011 Posted September 14, 2011 From what I'm hearing installers only record realtime because they can and the equipment will do it. Has anyone ever been in a situation where they missed something due to low fps, usually it's down to quality of the images and not quantity www.realsecurity.ie
mma Posted September 14, 2011 Posted September 14, 2011 From what I'm hearing installers only record realtime because they can and the equipment will do it. Has anyone ever been in a situation where they missed something due to low fps, usually it's down to quality of the images and not quantity I agree. Have had times were the images were useless because of a low resolution. Normally because the customer changed their mind on how long they want to record for. Only ever missed an incident due to fps in the days when you could get 50 fps across the board on a 16 channel dvr.
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