Update: Check out the latest post on this subject here:
If you read my previous tutorial: Batch Downloading and Converting Youtube Videos then you already know the second bit of this. Additionally, you may have noticed that sometimes Youtube videos just won’t download, or at least not fully. It is for this reason that we are going to use a program called ClipGrab http://clipgrab.org/
Download and Open clip grab.
Open your browser and find the video that you want to download and copy the Hyperlink
Sometimes with Vimeo videos embedded on other websites the ID is masked by a domain name; vimeo.com/eyemixear/video1 This will confuse clip grab, so just right click on the video where it says “Watch on Vimeo”
Then in your browser the hyperlink should look something like this: https://vimeo.com/72196298
Copy that and Alt+Tab back to ClipGrab it should have already loaded the hyperlink and say the name of the video. Leave the Format Original; Quality HD and click Grab
Select your destination and Wait.
Once your clip has downloaded open it up and check it out. Does it look good? Okay then visit my previous tutorial and finish the rest in MPEG StreamClip: Link Here
If you downloaded from Vimeo chances are that the above worked for you; if it didn’t, Switch the Format from Original to MPEG4 and give it a Go.
Sometimes with Youtube specifically the original format that was uploaded may be an out of date FLV which is separated into parts. To avoid a partial or failed download try letting clip grab pull the Mpeg4 clip for you.
Hope this helps and make sure to click the Donate tab in the Clipgrab About tab.