So lets start over from the beginning.
When you say, "it doesn't let me view them because of a software on the MAC called QuickTime Player (which is not as good as OBS).", what do you mean, exactly?
1. What are you trying to open? Exact filename.
2. How are you trying to open it?
3. What, exactly, happens?
As a quick example:
1. I am trying to open filename.flv
2. I am double-clicking the icon.
3. QuickTime player comes up, and says it does not know how to play the file.
If this is what is happening, then:
1. QuickTime player is the default media player on the mac. It does not handle .flv, as well as a few other movie types.
2. QuickTime player and OBS are completely different software. You cannot say that QTP is not as good as OBS -- they are doing different things.
3. If you right-click on a file, you will get a menu, including "Open With ...".
4. When you say "Open with", you'll get a list of all programs that are found by spotlight, that claim to open that type of file, that are able to run in that OS (and sometimes a few that won't run in that OS). Note that I did not say "in the applications folder", or "on the boot drive", or "installed in this OS" -- it is very, very hard to have a dual-boot setup, or even a disk image of an older OS installation, and keep it separate.
If you right-click, and "open with" only lists QuickTime Player, then you need to get a different program to play .flv, or you need to convert your OBS recordings from .flv to .mp4. (That is "remux recording".)
The two primary programs for displaying movies of any kind on the mac are "VLC" and "MPlayerX". They are similar, but not identical.
