My video clips which are pulled From OBS, do not line up on blender. I have A/V Sync on. the videos FPS on VLC say it is at 30 fps (plus the raw files DO sync when played back in VLC) and that is what I am trying to render at. Even though the channels do not line up when I render them they come out matching. Now when I try to make the channels line up when editing them and I try to render then the A/V is out of sync in the rendered video.
I just edited an OBS file in Blender's VSE and Blender auto-conformed the project frame rate to FPS: 10 FramerateBase: 0.330. So its not quite 30fps. If you added something else to the project first then added the OBS file later, then Blender will default to the first specified frame rate. Either try this rate or add the OBS file first.
Consider checking that you are using SDL as your Audio Device in Blender preferences.
I am not sure what the problem is with OBS FLV files and Blender but I changed my OBS output to mp4 files and the issue is not there with that type. It may have something to do with the FLV files not specifying a Frame rate. When I check the properties > details of the files there is very little information. Blender may just be trying to compensate?