Best settings for recording at a minimal size

[MorielM]

Just started using OBS. I'm using it to record my lectures on Zoom. One of the lectures recorded came out at 600Mb (the length is 2 hours) while another came out at 4Gb (for 3 hours). That's a pretty big difference, even though I didn't touch the output settings.

My current settings are H264/AVC Encoder with VBR (no other settings touched). I saw on the forums someone recommending x264 for better size-to-quality recordings. My main goal is to get the best quality while getting a minimal file size. Aiming for (optimally) less than 1Gb per 3 hours of recording.

Any suggestions would be highly appreciated.

 

[star099]

What resolution are you aiming for? And how powerful is your CPU? I'll show you how I set mine up for recording so you can test your setup.

Go to Settings > Output. In the Recording tab choose the following

Encoder: x264
Rate Control: CRF
CRF [value]: 24
Preset: Veryfast
Profile: Main
Tune: (none)

Now make a test video and record it for about a minute. While it's recording watch the main window. At the bottom right you'll see CPU usage in %. If it's low, good, you can change to a slower and thus higher quality mode. Switch Veryfast to Fast and then Medium if your CPU can handle it. If it gets over 60% you probably have to stop there. If your CPU is doing well, set the profile to high.

You can also try lowering the resolution and framerate to both speed it up and compress it more. 1280x720 and 24FPS should be good for a lecture.

Once you have finished testing what your CPU can handle, check the quality of the video. 24 is pretty low, but offers good filesizes if you don't really need that much quality. If it's not good enough, try 22, then 20, then 18 at the worst. By then the filesizes should be getting large.

Hopefully you find a setting that works for you. Screenshot below.