mp4 file expands wildly when shortening clip noob here,

I took a video of myself for a wedding greeting with my phone (LG Nexus 5 [Android]) sitting (the phone that is) in a windshield suction holder.
The video is 3'42" long and when downloaded to my PC from Google Photos it was 55 MB, more or less as expected.

I then wanted to edit out the beginning and end of the clip where I stand up from my chair to start at stop the video shooting.
At first I downloaded Lightworks, cut out the beginning and end and exported the sequence (for YouTube 720. My only other option not having the pro version was for Vimeo). The new file being 5% shorter took up 181 MB.

OK, so clearly there is some format/compression thing going on that I'm trying to avoid going too deep into.
Instead I found out I could just cut the beginning and on my phone hoping to preserve the native  formatting/compression. The editing tools there were rather coarse but it did the job. It then took forever to save the edited video. The new shortened video (still 5% shrunken) takes up 905 MB of space.

My question is. Is there a simple (and free) way to simply cut down the length of a video clip while preserving the formatting and compression so that the file will just shrink in size proportionally to the shrinkage of duration?

Looking forward to you advice.

Thanks
Simon
Not sure what's happening, but, when you export your edited film, keep an eye on the data rate. That's really how you keep files small. The lower the data rate is, the lesser the quality of the video image though.

So, when you export:


For a 720p final file, make sure your data rate is no smaller than 5
Mbps.
For a 1080p final file, make sure your data rate is no smaller than
10 Mbps.
Codec: H264.
Field order: progressive usually (depending on your raw footage).
Aspect: square pixel usually (depending on your raw footage).
Audio: AAC, 4100Hz, Maximum Bitrate.


Note: I'm not familiar with Lightworks' settings, so some of the options mentioned above might not be available to you when you set up your export.

Let us know if this keeps your file small.