Watch out, a whole story up ahead.
I can tell you that you have to spend money on a decent brand of WiFi webcams, especially when you want to create or incorporate it later in a full on surveillance system. Let me assure you, buying a mixed set of brands will bite you in the a.s.
WiFi camera's are a dime a dozen nowadays, and that is actually a problem. Every manufacturer has their own idea on how they implement features and how you can manage them. I have here a set of 9 TP-Link NC220 cameras. These need to surveil a house about 4000 square feet (2 floors). Not my house, but I am responsible for the operation of these cameras. Initially there was a reasonable decent WiFi modem router (fiber connection) placed pretty centrally located in the house. With my phone I could run around the place and have WiFi signal everywhere.
Anyway, so far so good. First I had to connect each of the cameras separately by a cable directly onto the router, than had to use my phone to detect the cameras and associate them with the WiFi network. I can only rename the cameras using my phone, even though each camera has it's own webserver/webinterface build into it. A lot of features can either be managed by phone or web interface, but not both. That gets old very quick.
Honestly, the cameras are not that bad, in and of themselves, but how the manufacturer "envisions" their use and management, that is, let me say it friendly, moronic. And most manufacturers have the idea that you will not use a computer at all to record the content your camera captures. Most of them don't even provide Windows software for their cameras anymore. Android or iOS, that is it.
Now, a decent surveillance system, in my eyes, needs to capture content and store it on hard disk (on-premise) and preferably also in the cloud. Camera manufacturers gladly offer you their services for a monthly fee and they try to get you to buy into their vendor-lock-in scheme. Be wary of that, those costs add up quickly and I know you are more than capable enough to make something better yourself. And after you take a look at what is provided, you will be cursing for 30 minutes at least and then lose significant amounts of free time making something better yourself.
The 'able to collect the content from all cameras and show this simultaneously on screen, while also recording to hard disk' part. Trusting the manufacturer to have (Windows) software available to accomplish this, that will bite you. I had to spend quite some time on not so savory looking websites to find an old version of Windows software that does provide this functionality, created by the manufacturer, who mentioned on their website that they don't support it anymore. Instead they offer you another feature to do this for another monthly fee. The software I found works good enough, but only with this model of camera.
Luckily there is independent software available that allows you to collect camera content from multiple brands and models. Some free, most of them pretty expensive and a few ask a monthly fee per connected camera. If you go this route, take a very hard and good look at what makes and models are supported. I tried a few of these, that stated they supported the NC230 and NC240 camera models. Yeah, that was a waste of time. Don't expect any support if the camera you purchased it is not mentioned in their list.
So, depending on your choice of camera, you are bound to step in a pile of misery, lack of software support and all of them wanting to bleed you dry on a monthly fee basis.
Do yourself a favor, getting a remote doorbell and an extra camera from the same model/make of cameras you want to use in your whole surveillance system is a much better idea than buying a mix-n-match of cameras. Don't get burned like I did and waste way too much time on getting these things to work.
Oh, I forgot. WiFi around the whole house, right?
....Right, not so much after installed half of the cameras. Let alone after all of them were installed. There is no option to select WiFi channels these cameras use, that is all handled automagically, because the camera knows best. Not only that, each camera claimed way too much WiFi bandwidth for the modem router to handle. Modem/router stressed, WiFi congestion all over the place. Have fun trying to explain to your significant other why WiFi on their phone is so shabby. They won;t accept an answer that states: because it's Tuesday, with a northern wind and the neighbor having his/her lawn mowed from right to left instead of right to left as he/she normally does.
I actually ended up buying several WiFi routers (APs are difficult to get here), "dummified" them so significantly that these act as an AP, and creating a single backbone UTP cable daisy-chaining each of the 'AP routers'. Luckily that option was available on the outside of the house. As long as the significant other does not see the cable, you won't have problems. A 'backbone' around the outside of the house does this perfectly. When entering the house, it was also easy to 'work away' a single UTP cable into the woodwork/behind furniture etc. The "happy wife, happy life"-concept at work here.
WiFi mesh networks I didn't even consider, way to expensive and bandwidth wise so far from the optimal solution that it isn't funny anymore. Especially for the amount of cameras in this house. Although the 'backbone' improved the situation, Laptops and the occasional computer connected by cable in the study rooms of this house worked like you would expect when connected to one of the 'AP routers' by cable. Wirelessly the experience still wasn't great.
So, wherever I could the WiFi cameras were connected by UTP cable anyway (5 of them) and then using the MAC addresses of each camera in the DHCP server from the original modem/router to "place" them at the end of the /24 range (like 192.168.1.201 for camera 1, 192.168.1.202 for camera 2 etc.). I did notice that often when a phone (Android or iOS) linked up with the WiFi network, the ping times of the WiFi connected cameras would shoot up significantly. Sometimes round trips take 50 times longer than when there was no phone linked into the WiFi network. Again, MAC addresses from phones that often link into the network are put even further back (192.168.1.211 for phone 1, ah, you get the idea).
With all that in place, no-one is yapping in my ear anymore about WiFi issues, all camera's work great and remain responsive even when 6 or 7 phones are linked into the network as well. Actually, a girl asked if she could use one of the study rooms during business hours to work with her (WiFi only) laptop, because it so much more stable than the Internet setup at her home. Ah well, for once the owner of the house can and does charge a monthly fee to her, which covers the monthly ISP bill and she can claim it as a business expense as she works a freelancer. Everyone happy.
Nextcloud (and a tool called: CarotDAV) is used to collect the captured camera content on my own (on-premise) cloud server some 15 kilometers away (no fees other than utility costs, the hardware and, in this case, one Internet connection).
I would suggest to get a pretty beefy computer. One that is able to encode the captured content, which is h264 for most cameras, to x265 encoding, this reduces the size of the files significantly. Also capturing content and encoding it to h264 is also pretty intense already if it must be done for 9 cameras at once. There is a rule: for each connected camera, add 1 GByte of RAM. Live by that rule. The computer that stores the captured content and does the encoding has 16GByte in total. Enough for the OS, the camera recording software and h264/x265 encoding.
Let me finish by saying that it is going to cost you more than you expect. In time, in grief and hardware. Be prepared.
A list of independent camera recording software I found during this project :
- IP Camera Viewer
: Windows-only, free version is quite limited and cannot record the video feeds from IP cameras or "push" these feeds to cloud. Their full version software can really do a lot and has hardly any limit on amount of cameras you can connect to it (90 USD).
: Linux-only, free, open source, comes with a smart phone app (static IP address for LVH would make this a much better experience).
: Windows-only, open source, should be able to collect video from cameras and show video from several (4?) cameras at once for free. Their commercial software can do a lot more, but monthly fees.
: Windows/Linux, commercial, free version is quite limited. Monthly fees look quite expensive for what you get.
: Linux, free, command-line management only. Collects video when a major part of the video signal changes.
: Windows/Linux, free/commercial, GUI-only server software, comes with desktop and mobile apps to view camera feeds.
: Linux, commercial, their cloud only.
: Linux, open source, free/commercial (monthly fee). Looks quite nice.
I think I'm still missing one: there was one that support 8 cameras for free, but it requires Windows Server machine and uses IIS 7 for content display. Looks really impressive, but requires significant hardware specs. Will look that up and add it later.