Q: convert VIDEO_TS folder to edit in imovie

Handbrake (Google it).

You need to convert the VOB files in the TS-Folder of the DVD back to DV which iMovie is designed to handle. For that you need mpegStreamclip:

http://www.squared5.com/svideo/mpeg-streamclip-mac.html

which is free, but you must also have the  Apple mpeg2 plugin :

http://store.apple.com/us/product/D2187Z/A/quicktime-mpeg-2-playback-component-f or-mac-os-x

(unless you are running Lion or later in which case see below))

which is a mere $20.

Another possibility is to use DVDxDV:

http://www.dvdxdv.com/NewFolderLookSite/Products/DVDxDV.overview.htm

which costs $25.

Or Handbrake.

For the benefit of others who may read this thread:

Obviously the foregoing only applies to DVDs you have made yourself, or other home-made DVDs that have been given to you. It will NOT work on copy-protected commercial DVDs, which in any case would be illegal.

And from the TOU of these forums:

Keep within the Law

1. No material may be submitted that is intended to promote or commit an illegal act.
3. Do not submit software or descriptions of processes that break or otherwise ‘work around’ digital rights management software or hardware. This includes conversations about ‘ripping’ DVDs or working around FairPlay software used on the iTunes Store.

If you are running Lion or later:

From the MPEG Streamclip homepage

The installer of the MPEG-2 Playback Component may refuse to install the component in Lion. Apple states the component is unnecessary in Lion onwards, however MPEG Streamclip still needs it. See this:

http://support.apple.com/kb/HT3381

To install the component in Lion, please download MPEG Streamclip 1.9.3b7 beta above; inside the disk image you will find the Utility MPEG2 Component Lion: use it to install the MPEG-2 Playback Component in Lion. The original installer's disk image (QuickTimeMPEG2.dmg) is required.

The current versions of MPEG Streamclip cannot take advantage of the built-in MPEG-2 functionality of Lion. For MPEG-2 files you still need to install the QuickTime MPEG-2 Playback Component, which is not preinstalled in Lion. (The same applies to Mountain Lion and Mavericks even though they have it preinstalled.) You don't have to install QuickTime 7.

I have the same issue.  When I went to the Handbrake website, this is what it said:  "For Mac users, please note the latest Handbrake version is compatible with Mac OS X 10.10, including the latest OS X El Capitan, so if you've upgraded to OS X 10.11, please proceed to a Handbrake alternative for El Capitan."  I'm running OS X El Capital version 10.13.13.  This alternative costs $35.  Does anyone have any suggestions that are free or have you used this alternative and it works?

I have the free download Handbrake 0.10.5. The VOB conversion feature works on my MacBook Pro running El Capitan 10.11.4.  

Thanks Rich839.  I'll try it right now.

I went to the Handbrake site again and it says it's for Mac OS X 10.6 - 10.11.  Since I'm running 10.13, do you think this means I should't try it?  And does anybody use the free Quicktime player that's on the Mac to do screen captures and conversions that way?

OK, now I'm really frustrated.  I can't get my Quick Time player to recognize my VOB files in screen capture mode, so I downloaded the old Quick Time 7 to see if that would work but it doesn't.  Handbrake specifically says it only works up to OS X 10.11 and I'm 10.13.13 so I don't want to download another program that doesn't work and eats up memory.  Any other suggestions?  I've spent all day researching this. I have DVDs that were converted from old VHS's and now I want to put these VOB files into iMovie for our daughter's wedding in 2 weeks but I'm completely stymied.    Any more suggestions would be greatly appreciated.

How did you copy the folder to your Mac desktop?  Mine are still on the external DVD hard drive I bought for my Macbook Pro.

Sorry. I realized I mis-read my version. Dyslexia is setting in.  I 'm 10.11.3.  Haven't even updated to 10.11.4.  So now I'll try Handbrake.  And I'm waiting for a call-back from the Apple iMovie folks.

Handbrake worked great for me too when I finally figured out how to download it past my Mac security.  It's converting my old VOB files in a usable format for iMovie.