# How Does OBS Change FFmpeg Params While Running



## Brian Leighty (Nov 20, 2017)

So I was curious if anyone knew how OBS is able to change things like bitrate while streaming without having to stop and restart like you do with FFmpeg. I didn't think this was possible but given that OBS is doing it and it's based on top FFmpeg I would think it should be possible in FFmpeg as well. Thanks.


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## dodgepong (Nov 20, 2017)

OBS doesn't use FFmpeg to encode unless you've explicitly selected FFmpeg in advanced output mode. Otherwise, it uses x264 directly.


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## pkv (Nov 20, 2017)

R1CH had implemented dynamic change of bitrate in OBS Classic which changes on the fly the bitrate of x264.
I've ported to OBS Studio but haven't had the time to push a PR; not sure many people are interested in that anyway.


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## dodgepong (Nov 20, 2017)

I think he is referring to the fact that you can open your settings while streaming and change the bit rate manually.


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