The firms are aiming to develop an optical disc that can be used for upcoming 4K content. The disc will be capable of holding at least 300GB of data and will need to be available by the end of 2015.
Normal Blu-rays currently hold a maximum of 50GB. Special triple-layer Blu-rays with a 100GB capacity do exist. Even larger quad-layer discs have also been promised.
However, neither of the special formats can be read by normal Blu-ray disc players.
Sony has previously gone on the record to say that 4K movies are likely to require more than 100GB of space.
Some commentators have questioned the need for a new disc format when streaming is becoming increasingly common. Sony itself launched a set top box capable of streaming 4K content earlier this year.
However, the company has countered that criticism saying that for the foreseeable future, there will be a sizeable number of potential customers whose internet speeds will be too slow, or data-use limits too restrictive.
Neither Sony nor Panasonic are referring to the new disc format as being used for 4K movies. Instead, they are referring to them being used as an archiving tool.
“Optical discs have excellent properties to protect them against the environment, such as dust resistance and water resistance, and can also withstand changes in temperature and humidity when stored,” they say in the press release announcing their plans.
“They also allow inter-generational compatibility between different formats, ensuring that data can continue to be read even as formats evolve. This makes them a robust medium for long-term storage of content.”
Streaming is increasingly eating into sales of Blu-ray discs and traditional DVDs. According to the British Film Institute, 179 million movies on discs were sold last year. That is a 14 per cent drop on the same figure in 2011.
Despite that, revenues were still significantly higher, with disc-based movies bringing in more than £1.5 billion compared to the £243 million generated by video on demand services.
However, video on demand revenues were up 50 per cent on 2011, revealing a huge increase in demand for the services.
Video on demand includes both streamed content and downloaded movies.