There dozens of 3-4 minute videos on youtube that interest me but there are one or two 10-15 second sections within each video that are of particular interest and I would love to be able to store just the 'cut down' version of each video for later reference.

 

I'd ideally like to 'crop' the videos on my Ubuntu box but I'd be OK n my iPad too. If I have to do it on my Windows box or my Android phone then so be it.

 

So what are my options?

Use a browser based youtube downloader like tubeninja.net and crop the movies in a simple editor such as the old windows movieMaker.

You can still find and download movieMaker (it was part of the Essentials suite) that will work under Windows 10. Apparently, the Windows 10 Photo app has similar functionality but I have never used it.

https://www.onlinevideoconverter.com/

 

https://video-download.co/

 

https://easyload.co/

 

Sometimes one works and then not another - a bit jit or miss.  Seems youtube tries to stop them and blocks somehow.

 

I have used ClipGrab for videos. It's a free download.

On my "Windows box" I would use a very conventional method.

 

Downloading complete video with Midrey Youtube Downloader.

Results in MPEG4 (H264/H265).

Resolution can be selected before download.

From experience the 720p resolution gives fastest downloads.

 

Then I use Avidemux to cut/crop. Quite easy to handle.

Allows proper cutting on (full) I-frames only (typically 2 seconds apart).

Not too much of a restriction for me.

For cut/crop just select "Copy" for video and audio.

 

http://youtubedownloader.software/

http://avidemux.sourceforge.net/

 

Avidemux would probably also work on your ubuntu (which I have zero knowledge about).