Just Want to Trim a Video - Do I lose Quality?

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I cut screencasts initially with OBS.  I then import that into Camtasia.  If I simply want to trim a bit off, then re-render it in order to save it as a video file again, am I losing quality?  The initial file format is a 4K (3840 x 2160) mp4 from OBS. 

Or better yet is there a way to resave without having to re-render?  If not what's the best options to retain original mp4 quality if imported?

I've included an example screen shot from Camtasia when I do a Share | File showing the options that are set by default when rendering back out to an MP4 again.  It appears to have retained the resolution, keyframe rate, etc. that I had set in OBS so seems to me like this would be lossless although I'm not familiar with other options such as entropy, Enable Smoothing, etc. yet and what that might do to the quality of my vid compared to the original I imported in.

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Posted 1 year ago

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Paul Middlin, Employee

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Yeah, you may lose a small amount of quality any time you re-encode a video. The MP4 format is not lossless, so it's unavoidable.
You can produce a small section of your timeline, so that you can quickly see the results of your settings changes. This way you can experiment a bit to be confident that it still looks good before you commit to rendering the whole thing.
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If you can import OBS into Quicktime, I believe its trim function does not re-render, it just cuts and saves the frames you want.

Just curious, why do you record in OBS instead of Camtasia?