Using OBS for recording multiple wireless mevo cameras

The advantages of our OBS setup is that all the files are centralized, their size is not too big, they’re synchronized by default, and we get a “mosaic” of the video sources, which is interesting for a first look at your study.

Before starting, the wifi router should be configured to create a local wifi hotspot (check with the manager of the Observation Lab), the mevo camera should be configured to connect to it and stream video in NDI using HEVC (see Tutorial), and OBS should be configured (see Tutorial) with proper plugins (source-record and NDI) + the mevo cameras NDI video sources should be added to it.

Now, here is the step-by-step deployment process of the mobile video booth with OBS and mevo cameras :

• plug the wifi router's power chord, and wait for it’s light to become solid blue (indicating that the local hotspot has been created)
• switch the mevo cameras on (long press on the button on the back). The back LEDs will “breathe”, then at some point they will stop, and the front LED will turn green, indicating that the camera is connected to the local hotspot
• plug the computer to the wifi router with a good quality ethernet cable
• start OBS, which would directly detect the video sources that you added previsouly
• check for potential lag in the video streams for some minutes
• start and stop recording with the bottom-right buttons in OBS
• check that all the video files are created and OK, at the “path” you configured

If your devices (cameras and computer) don’t manage to connect to the router, here is a possible testing procedure to check the wifi connection :

• plug the router with a ethernet cable to your computed, and connect to the router’s interface at 192.162.1.1 and navigate to “typology” : check if all devices are detected and considered connected
• ping one device from another (for example one computer from a phone)
• send OSC messages with Max/MSP ou purrdata (on the iPad or Android, use https://soundcool.org/en/) which is a simple and good UDP test
• test the “NDI Studio Monitor” application, from the NDI Core Suite that you installed
• then make a new test in OBS

If you get some lag and delays, for example when cameras are in different rooms and distant from the router, you can reduce the bitrate first, or even the resolution of the cameras (see Tutorial).

And if you get some lag and you don’t want to change the parameters of the cameras, you can anyway record locally, on the internal SD card of each camera, by pressing the button at the back of the camera. A short press starts recording (the front LED turns red), and another short press stops it. It’s a very good last minute emergency configuration that will work in any situation.

NB :

• We’ve run tests for more than 24h with 6 wireless camera (plugged only for power), and the setup stayed stable
• The most important thing in the setup is that the main computer with OBS should be wired to the wifi router with a good quality and short ethernet cable
• if cameras are too close to each other, it will maximize wifi interference and amplify the risk of lags and network drops
• OBS records the files when you stop the recording. It’s a fast process, but it implies that the software should not crash during use. Sometimes the files don’t directly appear when you close the software, or the software seems to crash when you close it, but there’s no danger here ! Wait for 2 minutes, then start the software again and the missing files will appear
• updating to a new version of OBS can make some plugins incompatible, and our whole setup is based on plugins. So never use the setup right after and OBS update. Take time to test everything again
• the OBS setup requires 20% of the computing power of the processor on the laptops of the Observation Lab, and a maximum of 5GB or RAM among 64GB
• each camera needs a network bandwith of around 12Mbps in h264 and 6Mbps in HEVC. We can imagine that a gigabit setup with 9 cameras, or even 12, would perfectly work
• each video file is around 3GB per hour