I'm cynical. If I saw the resume of someone who had a long-term job in some dying field, then went back to school for a degree in something else, and was applying for a job in that something else... I would immediately start wondering why he was so unemployable that he had to go to the extreme step of going to school. I don't like hiring extremely narrowly focused people, no matter how brilliant they are in that slender vein. Good people tend to learn a lot about subjects related to their primary expertise. Unless their previous careers were in dodo farming, that breadth will be enough to allow them to pick up another job without postponing their lives for a few years while they are spoon-fed new skills.

Your example suggests several possible related tasks: "analog video" -- well, it's alive and well. With computers, analog connectors are still far more common than DVI. "production" -- a lot of companies need producers, though most don't call them that. "Project Manager", maybe? My company does use the term producer, and most of our producers' tasks are more organizational and have little to do with exactly what is being produced. "broadcast" implies familiarity with a number of standards, workflows, and mentalities.

On the other hand, if I see some indication that someone returned to school because they were interested in the new field of endeavour, then I'll think more highly of them than of people who got the CS degree in the first place and haven't done anything else.

Of course, my knee-jerk reaction is completely unfair, because there are many reasons that the sort of person you're describing might be unable to find work despite having strong yet flexible expertise. Recruiters and HR people rely heavily on directly relevant experience appearing on a resume (and "directly relevant" often means "matching the keywords they were fed by the hiring manager"). My best advice, such as it is (I'm not in that situation so I don't really know what it's like), is to be sure to tailor both the resume and cover letter to every job applied for. It won't help as much for a megacorporation, where automated keyword scanners rule, but if you can get someone to at least read one or the other you'll have a chance, if you're quick, to address the question "why should I hire this person when he hasn't been doing exactly this already for the last 15 years?"

After all, the main question that a hiring company is asking is "will this person perform well in the position we are hiring for?" (There are other questions, such as "...and how much do we have to pay him?", but you need to get that far first.)