Google I/O is to kick off with a bang with the announcement of Google's new music service. But, if you were expecting an Amazon/iTunes rival then you're in for a shock - the Big G is launching Google Music without the backing of any record labels.

Instead, Google Music will be a cloud based locker for your existing music collection, allowing you to stream what you've already paid for (or ripped, or copied, or downloaded illegally) from its servers onto whatever devices it gets app approval for.

So that's Android and browser based for sure. We can't see Apple playing ball though - especially with its own cloud music experiment due to be announced next month.

The talk is that Google will offer storage for 20,000 of your MP3s for free - so more free space than Amazon - and there will be automatic playlist recommendations on board too.

Speaking to AllThingsD Jamie Rosenberg, who oversees digital content and strategy for Google’s Android platform, admitted that it was tough dealing with the labels.

He said: "Unfortunately, a couple of the major labels were less focused on the innovative vision that we put forward, and more interested in in an unreasonable and unsustainable set of business terms."

Rosenberg also confirmed the free aspect to the service, saying: "I think as Google typically does, I think the free aspect will continue to be very generous." 

Google Music will be announced at Google I/O today (10 May) and will initially be an invite-only private beta platform. The service will then roll-out in the US "within weeks".