Claire Enders, founder of the consultancy group, told Reuters: "We calculated the total jobs in the media in the UK at about 400,000, that includes newspapers, radio, TV, production companies, advertising, and so on, at the end of 2007.
"Between the beginning of 2008 and 2013 we're expecting half of those jobs to go. The big employers are the regional press, magazines, local advertising sales. Real numbers are in print."
Another analyst, Screen Digest's Vincent Letang, predicted a "long slowdown before a potential recovery in 2012".
"Newspapers are in a long term irreversible decline and it's only the beginning for them. It's a brutal slowdown," he said.
Newspaper and TV groups have already made large cuts to their workforces in response to declining ad revenues.
ITV is reducing its workforce by 1,000 to 5,000 by early 2009 while Virgin Media is to cut up to 2,200 jobs, 15% of its workforce, by 2012. Channel 4 is also reducing its workforce by 15%, cutting 150 jobs.
In newspapers, regional publisher Johnston Press has reduced its staff by 12% since the start of the year. Up to 90 jobs are to be cut at the Independent and Independent on Sunday, it was revealed last week.
In addition, 400 people have left papers published by the Daily Mail & General Trust.
On Thursday the Telegraph Media Group announced reductions amounting to 10% of its editorial staff, a move that will put about 50 journalists out of work.
Reports have suggested that the Financial Times could make a raft of job cuts later this week.