So… if you’re archiving, you’d normally make one high-quality master copy and then create the lower-quality streaming versions from that. Unfortunately, there are often reasons that you’d want multiple versions for streaming.

You also don’t always need to re-encode for streaming. It depends on why the format couldn’t stream in the first place. If you use the wrong container format for streaming (like you create an MKV file), then you can use -codec:v copy -codec:a copy and you’re not re-encoding anything. On the other hand, if you got a yuv444 and you need yuv420 for streaming, that requires re-encoding.