I would like help with resizing videos

Depending on the source format and the codec already in use, you could get lucky with HandBrake.

Do you know, what format, codec and resolution your original videos use? Where do they come from?
In order to find out, you can use one of the following three applications to analyse a sample video file.

• VideoSpec (free)
• MediaInfo (free)
• Media Inspector (2.99 USD € in the Mac App Store (MAS))

When done, you can use the "Report" (VideoSpec) and "Export" (Media Inspector) button to export a report,
attachable to your next post via the button.
In MediaInfo you have to go to the Menu Bar, select View > Text and copy the text via CMD+A > CMD+C and paste it via CMD+V into your next post.​

 

I was going to suggest handbrake too. Not sure you can automate it, but I'm pretty sure you can create jobs and add them to a queue to process one by one.

If you can some how get it to work by creating a automate script it will do the job.