Is Storage So Inexpensive You Should Record Continuously Now?

A 1Mb/s stream recorded continuously for 1 month requires 325GB of storage.

If you have 16 of them, that's 5.2TB.

If you recorded motion only, depending on camera positioning / scene complexity, you'd probably be looking at 2 - 3TB instead of 5.2TB. The argument then goes, you are only eliminating a single hard drive, which is not much money compared to 16 cameras.

Of course, 1Mb/s is a low estimate for an HD camera bitrate, presuming ~10fps and not a terribly complex scene (also no huge night time bandwidth spikes).

Screening hours of unnecessary video for an incident is painstaking. Recording based upon motion and other triggers reduces a time-consuming job considerably, making it more likely the surveillance system will be used to maximum advantage.

Looks like that is a comment I had on another thread. My comment about the motion flag was based on searching. Still, exterior cameras have to always be run continuous especially since with high definition we are usually looking at larger scenes. The thing is, the goal of our industry is to provide forensics for evidence and the percent chance of obtaining goes up exponentially if you record continuous. So what if it takes more time to search. 2 tb certified drives now are 150 bucks. I normally use vbr recording with reduced agc settings with a goal of 1 Mbps average on a 1-2 mp camera (main-high profile). This is achievable (reducing agc even a little bit helps alot to reduce bandwidth below trade show settings). Many integrators also think frame rate is linear in regards to bandwidth. Average cameras set for 1 fps continuous with higher rates for motion use more than half of the storage compared to continuous when you take into account the size of the key frame related to prediction frames. My main comment is that if a customer spends 1000 dollars on a camera, for an extra 15-20 bucks, they can increase their chance quite a bit for usable frames by going continuous. The bandwidth for the camera is used no matter if you store or not.

I think, whenever cost allows, video should always be recorded full time, and motion searching done retrospectively (assuming the video system has that feature). I have had cases where proving something didn't happen, for legal reasons, is as important as proving something did. With motion only recording, the court (and even myself) can never be 100% sure that the event didn't happen as it's too easy to misconfigure sensitivity or zones or due to some disk or processing error the motion event was never triggered.

Also typical motion recording settings may be designed to ignore objects far away on the grounds that faces can't be recognised at that distance anyway. But for serious incidents this video is still useful as it shows how many people were involved, which direction they came from and where they went to. It may also help determine which other cameras may have got a better image.

It is all about bugdet though ;)

OK, I will bite on this, which may cost me additional posts to back up my claims.

I know John stated that the more standard was 4 Mbps, but I do not buy this. I am a firm believer in VBR over CBR. Why on earth would you want worse video when action occurs. And why would you want top quality video when nothing occurs. Does not make sense. I took so long on this because I had to hijack a customers system (via Logmein) to confirm my results. (And had kids/camp situations during vacation week)

First of all, I live in Maine, where we have over 12 hours of night in the winter. I always design for "night" when I do systems. In my experience, we are in a mode of "bigger is better" but this is absurd. I have tested 1,2,3, and 5 MP cameras at night and none provide any better that a camera with a 1-2 MP sensor, so I stick to 1-2 MP (or 720-1080 if lower installed elevation). A matter of fact, I always though the Arecont AV3135 camera was "genius" with a day 3 MP and night 1.3 with no cut filter (Do not use now, but the concept is good). Anyway...

I went to a customer site and tested my "VBR" cameras. (Like I said, I do not understand the CBR philosophy). I was looking at "idle state" which occurs on average 80-90 percent of the time. All of the 1 to 1.3 MP cameras (1/30 or faster shutter) run at no greater than 600 kbps on main profile cameras in idle state (I do use High Profile cameras, which show better results). On total motion scenes this can jump to 2 Mbps, but on average, I would say 1 mbps (wait, is not that what I said in my post?). I decided to vary fps to see increases in bw/storage to back my claim that higher frame rate is not linear (do not direct this reponse to a past IPVM test). On a 1280 x 800 camera with multiiimage WDR, in idle state, and Q of about 30, Gov 1 sec, I was getting 450-600 kbps h.264 no matter the frame rate with a 1 fps value of 50 kB H.264 and JPEG of 85 kB. I verified this by sabataging the customers 100 camera system, setting 4 or the 1 MP cameras (VBR) to 10 fps, and only recording these to continous (none of the rest were recording). This was after hours, so there was no motion. The average per camera with mid level compression was 500 kpbs (I looked at the size of the storage file for the hour and determined average Mbps and then "un-hijacked' customer system).

Could someone tell me why they are running 4 Mbps BW on cameras. Is this for CBR mode just to cover the 10% instance when motion and complex scenes exist. I guess I can see a 5 MP camera in an airport or casino (no wait, Carl said he needs 30 fps so this can not be so), but how may interior locations need high resolution cameras. (I work daily telling customers why the 20 MP surround camera is a day only solution (competitors without Electical Engineering degrees like I have make these recommendations) and why the 5 MP fisheye can not view an area effectively unless in a 24 x 7 mall.

To restate, my theory is no greater than 2 MP for exterior (use more if needed instead of higher resolution) and normally 1.3 MP 4:3 for halls or low hanging 720/1080 with 16:9 for larger areas. Depth of view reduces ability of higher resolution cameras in hallway areas, so < 1.3 MP with more cameras (heck, 1.3 MP domes are now <$150) is the norm. Strive for 1 MBps average (wait, once again, is not that what I said in my original post). Use multiimage WDR for entry doors and exterior window/glass areas. Always use < 1/30 second shutter. Get rid of 2x and 4x Sensup. (trade show marketing, I think).

1 Mbps ( I say less than this per average per average camera) = 325 GB per month. 2 TB drives = $150 continous per camera @ 30 days = $25 (continuous motion cost per camerea per month)

See original post. (If anyone backs up the claim by John that an IP camera can be installed, programed, and licensed for $400 for a system, I would like to hear it - our average is $1000 per interior camera installed, licensed programmed, and commisioned - if they can, I was thinking of getting into solar energy).

I prefer to keep constant recording in addition to motion recording. I have recently been setting up my analog installs with D1@7FPS normal recording (constant) with VBR cap @512Kbps, then also motion recording with D1@7FPS with a VBR cap of 1024Kbps. While the normal recording has the same resolution and frame rate, the lower VBR cap cuts down on the additional storage needed. To be honest, most of these analog installs are small camera counts (8 cams usually) and a single 2TB drive is more than enough for a full 30 days retention. And the best part is my customer still receives motion cues that they can use to cut down on forensics time.

Now for our IP projects, they tend to be larger camera counts and vary greatly depending on the type of customer. For instance, an apartment complex we are working with right now in the planning stage is going to need 15 IP cams (13-1080p outdoor, 2-720p indoor) and we are proposing 9TB (3x3TB) of disk space. At $450 cost of the actual drives, how could we not think of drive cost as a minimal part of the cost of the project. It is a mere fraction of the overall cost.

We will be recommending constant recording for almost all customers going forward, unless Thailand floods again. (too soon?)