The Real Truth of SMD as I See It

Jan 1, 2024
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There are a lot of people out there who say SMD is bad, and unfortunately, that kind of thinking makes others stop using a feature that could actually improve their security. The truth is, SMD has advantages that IVS just doesn’t offer, and both systems have their place depending on the situation.

One of the biggest benefits of SMD is its ability to filter out unwanted motion while still giving you control over the types of alerts you receive. With IVS, if you have a tripwire or intrusion rule set up, you get an alert no matter what triggered it. With SMD, you can choose whether you want to be notified about humans, vehicles, or both. That kind of flexibility makes a difference, especially when you’re using an app to monitor activity in real time.

People who use full-time recording with IVS might complain about SMD because they’re focused on keeping their timelines perfectly segmented, with green for full-time recording and blue for IVS-triggered events. If they enabled motion detection with SMD, they would get extra recordings and alerts, which they see as clutter. But that doesn’t mean SMD is bad—it just means they don’t need it for their specific setup. In fact, SMD can be a game-changer for those who don’t record 24/7 and need better filtering for motion-triggered events.

In areas with a lot of environmental triggers like rain, snow, and bugs, SMD helps filter out unnecessary motion that would otherwise send unwanted alerts. But even more importantly, there are times when SMD will capture an event that IVS might miss. If heavy rain or snow is covering the lens, IVS tripwires can fail because they rely on a clear, defined crossing to trigger an event. SMD, on the other hand, works based on motion in a grid area, meaning that even if a person or vehicle is partially obscured by weather, it still has a chance to register. The same applies at night, where certain conditions might cause IVS to miss an event that SMD could still detect.

People need to stop telling others to avoid SMD entirely. It’s not about choosing one over the other—it’s about understanding when to use each tool. If SMD improves coverage and captures events that IVS might miss, why not use it? Security should be about what works best, not just following what others say.

Plus, when it comes to my AI DVRs, which only have a few IVS channels but offer SMD for the rest, why wouldn’t you use SMD instead of relying on basic motion detection? Some people say not to use built-in AI because it supposedly lowers the recorder’s performance, but I haven’t seen any issues with that on my Amcrest 7108-AI or 5108-I3 8MP DVRs.

In the 3rd picture that is showing the SMD in search with Human and Vehicle picked and added ch1 that is IVS with a tripwire. First picture is just SMD channels in Motion search before adding the filters that is again the 3rd picture.. Center or second picture is doing just SMD Ai search from Ai menu..
 

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I'm with you on SMD.
I use SMD, IVS and continuous recording. IVS for all the alerts (at least on my phone is shows human or motor vehicle on detection) and SMD just so I can use the search area tool.

Searching by SMD area allows you to pick an area and only show person/vehicle's detected in that area. I use it with the SMD/motion covering the entire camera view.
1742976081253.jpeg
 
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Thank you for pointing that out, As I do use that as well just sometimes easier when i am in a hurry to just pick the event looking for before doing the start of playback. But yes for an area that is full scene with lets say like my channel 3 if it was recording the street and not just the driveway seeing I have other camera that is recording the street with IVS for human already.. Anyway in your method and one that I didn't mention again thank you for bring it up for a better all the way around search, If i was doing both front road and not just my driveway. I could do as you did pick the person area after starting playback, Then set the grid area.. Then it only plays back that area and in my case the road wouldn't be played back.. So another great feature and a way to pick out just an area of a larger scene..
 
SMD is good if you need to separate all human/car traffic (SMD) and some specific actions/triggers (IVS) on cheaper / lower cams..

but on modern cams (5442-S3, 7442-X) SMD was replaced by AcuPick 2.0 / mini Video Meta Data for that..

With AcuPick 2.0 you can search not only by human/car/animal filter but also age/sex/color/cloth types&colors/car color etc..

And still you can have IVS for specific actions / triggers...

AcuPick / Video Meta Data have much better search & browse functionality over NVR web interface (SMD have very weak functionality here)..
 
While AcuPick and Video Metadata offer superior search and browsing capabilities via the NVR web interface, not everyone has access to these features. SMD still serves as a solid alternative for those using budget-friendly or older hardware, offering a middle ground between basic motion detection and the full AI-driven analytics of modern systems.

Ultimately, it’s about using what works best for your setup. If your cameras and NVR support advanced metadata filtering, then AcuPick is the way to go. But if you’re working with older cameras and need a way to filter human and vehicle activity without upgrading everything, SMD is still a valuable tool.

Sure, let’s go ahead and tell everyone they need brand-new cameras just to get better filtering—when in reality, they could just start using a feature they already have but were told not to. I’d bet there are way more people out there who could be using SMD on their current DVR or NVR but don’t, simply because someone said it would slow down their system.

The truth is, SMD is built into plenty of DVRs and NVRs that people already own, and it does a solid job of separating human and vehicle motion from random triggers like rain, snow, and bugs. Instead of spending money upgrading everything, why not take advantage of what’s already there? The idea that it tanks performance is mostly overblown—I haven’t seen any slowdown on my Amcrest 7108-AI or 5108-I3 8MP DVRs.

Yes, newer cameras have fancy features like AcuPick 2.0 and Video Metadata, allowing for super-detailed searches with filters for age, gender, clothing color, and more. But not everyone has the budget for that, and not everyone needs it. For a lot of people, SMD is already a huge step up from basic motion detection, and it’s just sitting there unused because of bad advice.

Instead of pushing people into buying new gear, maybe it’s time to start looking at what’s already available and making the most of it.
 
When folks here say that, they are responding to people that have a camera with IVS and are not using it and wondering why SMD is giving lots of false triggers....

You are talking about a completely different use case than where the advice is given....
 
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1) Yes, If you have old dumb cameras, and an NVR/XVR that does limited AI and has SMD, (But NOT IVS) then SMD can be helpful for those cameras and is an upgrade from old fashioned MD which is pixel based dumb motion detection.
Otherwise, there are better choices (IVS/VMD/AcuPick) in 99% of the questions we are asked here.

2) The only use case I can see other than dumb cameras is the one @Mark_M shows, where you have a very specific area you want to see if SMD detected a human or car. (I rarely see cars in my yard however)
Even then, I would prefer to simply use an additional IVS rule for an area of concern.

3) And Yes, turning on Recorder based AI on most Dahua NVRs DOES INDEED reduce performance of the NVR. Nobody says it "tanks" or "slows down" your system it, but it does cut incoming bandwidth capability by 40+%.. If you have an NVR loaded up close to bandwidth capacity and turn on Recorder based AI, you WILL see cameras drop out.
Read the specs - here's the most commonly referred NVR currently the NVR5216-16P-EI
Network Bandwidth

AI disabled: 384 Mbps incoming, 384 Mbps recording and 384 Mbps outgoing

AI enabled: 200 Mbps incoming, 200 Mbps recording and 200 Mbps outgoing


4) SMD detects the ENTIRE screen area regardless of what you set in MD.
I don't want to know a car passed 300ft away on the highway just because SMD saw it in the overall scene in the distance. If I did, I'd set a separate IVS rule for that area
I only care about cars passing within 40ft of my house, and even then I dont need SMD to do that as IVS can do it better with Direction of Travel

  • As far as separating Human from Vehicle alerts, my IVS does that now in DMSS.
  • And I can set separate IVS rules for Humans or Vehicles or both, decide how/if they alert me, AND with IVS I can set parameters such as Direction of travel, which can be a huge differentiator..
  • If I have so much traffic I need to separate Human vs Vehicle in my NVR Search results, I use AI Visual search
  • We routinely see questions about why a user is getting so many "false" alerts. With SMD I have to explain to them that it sees and activates on the entire scene and makes no differentiation between the furthest left corner area which happens to be in their neighbors yard across the street, vs the small grid directly in front of their door.

A case can be made for every feature ever implemented on every camera and on every NVR.
There are thousands of use cases and I'm sure we can find one use case for every obscure feature ever incorporated into any NVR or camera made in the last 10-20 years.

I would say 90%+ of the people coming here asking questions have newer AI enabled equipment and are learning how to use it. I would not tell someone to buy new equipment if all they need is to turn on SMD (IF their NVR supports it) for their old dumb cameras, but I would also let them know there are better aletrnatives if they want/can upgrade. Most simply have no idea what technology is even available.

* I actually use old fashioned MD on a small area on my back porch, to detect critters on my porch, only at night.
**My old LP turntable works just fine and there are a few obscure things I can do with it that I can't with digital sound equipment, but it's in a box in the shed....
 
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Lets look at ONE real world hour in front of my house.
(I'm using SmartPSS lite for playback for this demo as IMHO its better and easier than the NVR Search Playback., But both show the same thing)

The NVR recorded 12 Total Events in that hour.
No Events were "missed"

  • IVS Saw 10 (Blue)
  • SMD saw 12 (Yellow)
SMD1.jpg

Lets see what SMD caught that IVS did not on those extra 2 Alerts:

First "Event"
View attachment 192.168.1.110_ch2_20250326090139_20250326090152.mp4

Second 'Event"
View attachment 192.168.1.110_ch2_20250326095657_20250326095708.mp4


The 1st 'Event" trigger that SMD saw that IVS didn't was wind blowing a leaf and the spanish moss. No Human or Vehicle
FALSE ALERT

The 2nd "Event" trigger that SMD saw that IVS didn't was a shadow of an overhead Bird
FALSE ALERT
 
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Per the above and my longer post above that, IMHO:

SMD is generally inferior to IVS, creates many more false alerts, and should only be used in very specific instances where IVS is not available
 
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1) Yes, If you have old dumb cameras, and an NVR that does limited AI and has SMD, (But NOT IVS) then SMD can be helpful for those cameras and is an upgrade from old fashioned MD which is pixel based dumb motion detection.
Otherwise, there are better choices (IVS/VMD/AcuPick) in 99% of the questions we are asked here.

2) The only use case I can see other than dumb cameras is the one @Mark_M shows, where you have a very specific area you want to see if SMD detected a human or car. (I rarely see cars in my yard however)
Even then, I would prefer to simply use an additional IVS rule for an area of concern.

3) And Yes, turning on Recorder based AI on most Dahua NVRs DOES INDEED reduce performance of the NVR. Nobody says it "tanks" or "slows down" your system it, but it does cut incoming bandwidth capability by 40+%.. If you have an NVR loaded up close to bandwidth capacity and turn on Recorder based AI, you WILL see cameras drop out.
Read the specs - here's the most commonly referred NVR currently the NVR5216-16P-EI
Network Bandwidth

AI disabled: 384 Mbps incoming, 384 Mbps recording and 384 Mbps outgoing

AI enabled: 200 Mbps incoming, 200 Mbps recording and 200 Mbps outgoing


4) SMD detects the ENTIRE screen area regardless of what you set in MD.
I don't want to know a car passed 300ft away on the highway just because SMD saw it in the overall scene in the distance. If I did, I'd set a separate IVS rule for that area
I only care about cars passing within 40ft of my house, and even then I dont need SMD to do that as IVS can do it better with Direction of Travel

  • As far as separating Human from Vehicle alerts, my IVS does that now in DMSS.
  • And I can set separate IVS rules for Humans or Vehicles or both, decide how/if they alert me, AND with IVS I can set parameters such as Direction of travel, which can be a huge differentiator..
  • If I have so much traffic I need to separate Human vs Vehicle in my NVR Search results, I use AI Visual search
  • We routinely see questions about why a user is getting so many "false" alerts. With SMD I have to explain to them that it sees and activates on the entire scene and makes no differentiation between the furthest left corner area which happens to be in their neighbors yard across the street, vs the small grid directly in front of their door.

A case can be made for every feature ever implemented on every camera and on every NVR.
There are thousands of use cases and I'm sure we can find one use case for every obscure feature ever incorporated into any NVR or camera made in the last 10-20 years.

I would say 90%+ of the people coming here asking questions have newer AI enabled equipment and are learning how to use it. I would not tell someone to buy new equipment if all they need is to turn on SMD (IF their NVR supports it) for their old dumb cameras, but I would also let them know there are better aletrnatives if they want/can upgrade. Most simply have no idea what technology is even available.

* I actually use old fashioned MD on a small area on my back porch, to detect critters on my porch, only at night.
**My old LP turntable works just fine and there are a few obscure things I can do with it that I can't with digital sound equipment, but it's in a box in the shed....

This exactly!

When a thread starts with "I just got this 54IR-ZE-S3 and I am getting a lot more false triggers than the Reolink it replaced and have SMD on the most sensitive setting", then yes we point out that SMD sucks for that and IVS is superior. We are not talking about a 15 year old camera that only supports MD/SMD....

Most of the posts that start here are with people that have brand new cameras, not some 15 year old NVR or camera that they are finally getting around to figure out how to eliminate so many false triggers.

So we are not telling people to buy new equipment because their post is about a brand new piece of equipment they just bought....we are telling them about the benefits of the AI on the camera in their hand.....

That is why we ask the questions we ask and provide advice based on the equipment they have.
 
Lets look at ONE real world hour in front of my house.
(I'm using SmartPSS lite for playback for this demo as IMHO its better and easier than the NVR Search Playback., But both show the same thing)

The NVR recorded 12 Total Events in that hour.
No Events were "missed"

  • IVS Saw 10 (Orange)
  • SMD saw 12 (Yellow)
View attachment 217659

Lets see what SMD caught that IVS did not on those extra 2 Alerts:

First "Event"
View attachment 217658

Second 'Event"
View attachment 217657


The 1st 'Event" trigger that SMD saw that IVS didn't was wind blowing a leaf and the spanish moss. No Human or Vehicle
FALSE ALERT

The 2nd "Event" trigger that SMD saw that IVS didn't was a shadow of an overhead Bird
FALSE ALERT

And this is a tight field of view and in one hour had two false alerts.

Imagine a wider view with more things able to be seen blowing in the wind - taller trees, flags, leaves, etc. and the false triggers become too much and why someone comes here asking for advice on their brand new camera how to minimize the false triggers.

If someone did a similar test with a wider view, the results would be way more SMD false than positive.

Either that or they turn off the alerts, which kinda defeats the purpose of having a system to begin with.

I don't get 2 false alerts in year on all my cameras combined using IVS.

This is why we ask what camera make/model if they don't provide it in the original post.

We try to "know the audience" and provide the best advice for their situation and sometimes ask the obvious question to provide the best advice.

It isn't our fault if someone with a 15 year camera that only has SMD (which would be the best option on their camera) reads a post where someone says SMD sucks when the comment is being made in comparison to IVS on a completely different camera and decides not to use SMD on their 15 year old camera because of it....

Who uses Dahua AI capable cameras? Reliable AI for triggering events? Pro's/con's?
 
Just to close this out so i can turn it off...
Just totaled from 8am until 2pm - 4 hrs on my quiet little street (happened to have a few contractors by so much busier than usual)

Total alerts recorded for that camera 71
Total IVS Events - 57
Total SMD Events 71

So 14 False SMD alerts.
 
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Just to close this out so i can turn it off...
Just totaled from 8am until 2pm - 4 hrs on my quiet little street (happened to have a few contractors by so much busier than usual)

Total alerts recorded for that camera 71
Total IVS Events - 57
Total SMD Events 71

So 14 False SMD alerts.

And 14 false events in 4 hours is why people turn alerts off....
 
IVS—I'd love to see an IVS setup that lets you choose whether a Tripwire was triggered by a human or a vehicle. As you can see from my picture below, Tripwire is just a basic event with no filtering, while SMD gives you a dropdown where you can pick exactly what you want to trigger an alert. The latest update even added a PET option, making it even more versatile.

My whole point is AS I SEE IT. The problem is that when enough people keep saying not to use a feature, those who could actually benefit from it might never even try it. It’s not about calling out any single post or person—it’s about making sure people aren’t dismissing something that could actually improve their security.

You’ve probably noticed I’ve been talking about my DVRs this whole time, not my NVRs. That’s because I’m not making a blanket statement about every system out there. I’m just pointing out that SMD is a tool that exists, and people should at least consider using it instead of writing it off based on one sided advice.
 

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IVS—I'd love to see an IVS setup that lets you choose whether a Tripwire was triggered by a human or a vehicle. As you can see from my picture below, Tripwire is just a basic event with no filtering, while SMD gives you a dropdown where you can pick exactly what you want to trigger an alert. The latest update even added a PET option, making it even more versatile.

My whole point is AS I SEE IT. The problem is that when enough people keep saying not to use a feature, those who could actually benefit from it might never even try it. It’s not about calling out any single post or person—it’s about making sure people aren’t dismissing something that could actually improve their security.

You’ve probably noticed I’ve been talking about my DVRs this whole time, not my NVRs. That’s because I’m not making a blanket statement about every system out there. I’m just pointing out that SMD is a tool that exists, and people should at least consider using it instead of writing it off based on one sided advice.

But yet you do jump in to posts stating your advice based on YOUR experience with your dated DVR that is totally different than the equipment a respective thread's OP is talking about and ends up being dated advice not applicable to the equipment being discussed.

I do not think anyone here would say to use SMD over IVS for a modern Dahua OEM camera.

Like I said, if someone comes here with 15 year old equipment and is wanting to reduce false triggers and reads a post about a modern 5442-S3 camera where someone says do not use SMD as IVS is better and they conclude from that they shouldn't use SMD, which is the best option on their 15 year old stuff, that is on them.

You provide great insight and some great historical stuff and your knowledge of taking apart cameras and stuff is great and I enjoy reading those, but just like you are accusing us of one-sided advice, your dated advice on modern cameras that you do not own is one-sided and is providing dated advice to someone with a modern camera that has more capabilities than the cameras you are referring to.

As I said, most of the posts people start are with brand new gear they just bought, not a 15 year old system with dated capabilities and the advice we give them is applicable to the device they have.
 
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Where is the setting for leaves and bird shadows?
 
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Yes if I still had my XVR and a bunch of CVI cameras, I MIGHT use SMD on channels AFTER I max'd out the IVS capabilities.

My last 7000 series XVR had 10-12 IVS channels (I forget which) and I had 6 analog cams and 6 IP cams on it that obviously had their own IVS so I had no need for SMD

But if you have an old XVR that doesnt have IVS capacity or not enough, and you have all analog cameras, then by all means use SMD
(Said that in #1 on my very first comment)
 
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But yet you do jump in to posts stating your advice based on YOUR experience with your dated DVR that is totally different than the equipment a respective thread's OP is talking about and ends up being dated advice not applicable to the equipment being discussed.

I do not think anyone here would say to use SMD over IVS for a modern Dahua OEM camera.

Like I said, if someone comes here with 15 year old equipment and is wanting to reduce false triggers and reads a post about a modern 5442-S3 camera where someone says do not use SMD as IVS is better and they conclude from that they shouldn't use SMD, which is the best option on their 15 year old stuff, that is on them.

You provide great insight and some great historical stuff and your knowledge of taking apart cameras and stuff is great and I enjoy reading those, but just like you are accusing us of one-sided advice, your dated advice on modern cameras that you do not own is one-sided and is providing dated advice to someone with a modern camera that has more capabilities than the cameras you are referring to.

As I said, most of the posts people start are with brand new gear they just bought, not a 15 year old system with dated capabilities and the advice we give them is applicable to the device they have.
^^^All of This
 
To be fair, whenever people would come here asking about an NVR versus BI, I would share my horrible experiences with NVRs (which were dated) compared to my experiences with BI.

Between @bigredfish education and my recent experiences helping friends and neighbors set up modern day NVRs, my tone has softened and now I simply link a BI-versus-NVR search link for people to review whenever that question is asked and do not go into details.

I am sure that @bigredfish and other NVR lovers haven't realized my toned down approach LOL.

Now that doesn't mean I am switching to an NVR anytime soon and my preference is still BI LOL, but I have a better appreciation as to what the current NVRs are capable of.
 
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