SEO for video content that is duplicated accross a larger network

[PlusROI]

I have a website with lots of content (high quality video clips for a particular niche). All the content gets fed out 100+ other sites on various domains/subdomains which are reskinned for a given city. So the content on these other sites is 100% duplicate.

I still want to generate SEO traffic though. So my thought is that we:

a) need to have canonical tags from all the other domains/subdomains that point back to the original post on the main site

b) probably need to disallow search engine crawlers on all the other domains/subdomains

Is this on the right track? Missing anything important related to duplicate content?

The idea is that after we get search engines crawling the content correctly, from there we'd use the IP address to redirect the visitor to the best suited domain/subdomain. any thoughts on that approach?

Thanks for your help!

[PlusROI]

Thanks James for your responses. To clarify, there is indeed a good and necessary reason in this case to have a unique domain in each city under it's own brand. The other domains (or subdomains), are subsections of larger sites that already have their own established authority and users. In fact, the main site is unimportant except as the original place where the video content is published.

That said, we understand duplicate content spread out over many domains is not going to work when it comes to SEO, so we're trying to figure out the best way to get the content (high quality timely videos) found in search and then passed along to the most relevant local site for that user.

Your answer addresses my question about canonicalization and blocking crawlers, so thank you! If you happen to have any other thoughts on things we ought to be watching out for those thoughts would be welcome.