Downloading/Sending video from my iphone to some other device in different ways

You should try the following:

• If you have it, do try with iMovie. (Menu “File” -> “Import Media…”)
• Try AirDrop. You have to be on iOS 8 and Mac OS X Yosemite for AirDrop to work between an iPhone and a Mac though.
• If you can successfully make a backup of your iPhone using iTunes, I can walk you through the retrieving of the video from the iTunes backup.
• If you can upload the video to YouTube, there are ways to download videos from YouTube. It’s way easier than you might think actually.

Don’t hesitate to comment for questions and precisions.

By all means, if you can get the reason why the transfer fails with Image Capture, please tell us, it will probably help (see my comment on your question).

Try a peer-to-peer file transfer service to move the video directly from your phone to computer, like BitTorrent Sync. This would be faster then using a cloud solution like uploading to Dropbox or YouTube and then downloading it again. It's very simple to use too, just download the BitTorrent Sync app on your phone and Mac, turn on the Camera Roll backup feature from you phone, and then send the link to your Mac to begin the transfer. This is the probably the fastest way to transfer files with out a wired connection.

You might want to try iExplorer. Because it can directly access your iPhone as a disk device, iExplorer may be able to move the movie file to your Mac without any of the problems associated with other apps.

iExplorer can also open and read iTunes backups, which may be another way to extract the movie. My wife inadvertently wiped her iPhone a few months ago, but I was able to recover all her photos, which included a few movie files, from an iTunes backup.

A free version or iExplorer is available, but if it works for you, purchasing the app is a great idea. I'm not sure what restrictions are on the free version, though.

Transparency: I'm just a very satisfied user of iExplorer, and will obtain no financial gain should you purchase a copy.

I use Photo Transfer app http://www.phototransferapp.com to transfer photos and videos between my iDevices and my Mac, though I admit I haven't tried to transfer as large a file as you need to do. It supports lots of formats and preserves the metadata, too. It uses WiFi or Bluetooth.