The reason I'm looking at OpenWrt is mainly because it's what I use in different projects.
I'm not looking for CCTV servers as I'm well aware of ZoneMinder for example which I've been using for many years. I'm also not actually asking about IP cameras, I use those all the time.
I'm asking about those little wireless cameras you can buy online such as this one.
These simply act as an AP and need an app to be viewed. These kinds of cameras are what I'm talking about. I don't use the radio on my router so wondered if I could somehow see the video of one of these little cameras.
I'm not concerned about security as nothing would be put onto the Internet. It's just hacking, learning, finding reasons to play with OpenWrt.
I think the real question is what can you do with this camera without the special app... It's certainly possible to configure a device running openwrt to connect as a client to an AP provided by a camera. Beyond that... it's anyone's guess.
Given the size and price of these devices, I'm confident it's a microcontroller-based IP camera system similar to the far more open and friendly ESP32 Cam, that I recommend you check out instead if you want to have more fun times, or at least to learn how these things actually function under the hood before you don the hacker hat and try to reverse-engineer them.
I understand, but I don't think there is much that OpenWrt can do about those things.
It is still an IP camera system like any other, all the work is either done by the IP camera system (encoding the media) or the viewer device (the PC or device with a screen).
Although this device adds two big limitations that would require significant effort to overcome:
It's requiring you to use an app so you need to reverse-engineer the app to understand wtf it's doing and how to make a client for it. It's garden-variety app reverse engineering due to what this is most likely doing, but it's still a hassle.
since all these things generate an AP and expect to be used by a single device at a time it's reasonable to assume they have the same IP and network configuation that you can't modify. You would need to do some hectic routing configurations to actually connect more than one at a time to an OpenWrt router, or find a way to modify its firmware to change the IP and whatnot. This is a microcontroller though so the firmware is a single executable blob.
ESP32 Cam has neither of these issues.
To see the video feed you are just visiting a webpage hosted by the device itself (similar to what IP cams do). Yes it's a microcontroller with a web server, be very afraid
you have full control over it's settings and configuration either through a basic web interface or by hard-coding it in the firmware source code before compiling and flashing it, so you can have any number of these things join any network you want with little hassle
I think it is clear that OpenWrt has nothing to do with the operation of wireless cameras. Of course you can connect wireless cameras to any router or AP, and depending on the capabilities of the router you can connect more or less cameras. I have an installation of this type with five cameras in a small business of a client, and the first problem is that this type of cameras usually provide three display systems, ActiveX, Flash and Java; the first two are no longer supported by modern browsers, and I think java will stop being supported shortly, precisely because of the NPAPI technology. In my case we have public ip and port mapping to access from outside.
AFAIK the vanilla ESP32 Cam has no default case because it's a devboard, but you can find dozens of 3D printed case designs to enclose it.
If you want something that looks like a finished product with a case and everything from the start, you should look for M5Camera, which is using the same hardware as ESP32 Cam, but in a more compact board to fit in a small case.
The cheaper and less-powerful model of M5Camera can be bought for 15$ on Aliexpress and similar (and the "more expensive" costs 20-25$), which is more or less the same price as the ones you were also looking at.