I downloaded OBS to try to record some online lectures with low size. I tried some other software already, but the file sizes and quality were too high. I'm trying to keep the file size as low as possible. I plan to record about an 1/1.5 hours at a time of video w/ computer audio, and the resolution, frame rate, and audio quality, etc. can all be very low as I will already have handwritten notes. I'm new to OBS, so I'm wondering what settings I should change to accomplish this. All other software I've tried have huge file sizes, so I want too make the size as low as possible such that the text is still legible and the audio is still audible.
I'm not sure if OBS can actually handle that, but you can always fallback to external video encoding using e.g. ffmpeg. This enables you to compress your results really hard, lowering the resolution & bitrate to your liking. Because I don't know the file size you are aiming for, I won't give you concrete parameters here, but there are plenty of tutorials online that can tell you how to play around with those values.
I intend to use OBS with the same objective but I'm getting pretty large files as well. Aiming to get 300mb ish videos and I'm ending up with 800mb - 1gb... and lowering bitrate and resolution didn't seem to make a difference.
While I wait and continue to look for an answer with a specific setting reccomendation, I'm using VLC to try and compress the recorded files. Don't know if this is useful to you, but on VLC go to "Media", then "Convert/Save", choose your recorded video and set the file type and settings you need. Manage to get it down to at least half the original file size.
Hope someone who actually knows what they're doing come and help soon haha